Tag Archives: science

Physics1 Defining Forces in Physics

The word force has lots of meanings. Most of them have nothing to do with physics. How are forces in physics defined?

forces in physics can leave an object sitting still

The block is sitting not moving on the table. Is a force acting on it?

Question: What are forces in physics?

Materials:

Block of wood

Table

Wire with a crook at the end

Procedure:

Set the block of wood on the table

Observe the block for a minute

Push on the block

forces in physics include pushing

Pushing on the block made it move across the table. Pushing is another kind of force.

Use the wire with the crook to pull the block

Push the block off the edge of the table

Observations:

What the block of wood does sitting on the table:

What the block does when you push on it:

What the block does when you pull on it:

What the block does when you hit the table:

What the block does when you push it off the table:

Conclusions:

What makes the block move?

Is a force acting on the block as it sits on the table?

Why doesn’t the block move because of this force?

How do you know a force is acting on the block?

How does a force act?

How do you think forces in physics are defined?

forces in physics include pulling

I forgot to grab my wire to pull the block across the table. Fingers do work to apply force by pulling.

What I Found Out:

My block of wood did not move sitting on the table. It only moved when I pushed or pulled it.

A force is working on the block as it sits on the table. When the block is pushed off the table this force pulls it to the floor. The only reason the force couldn’t move the block before is because the table was in the way.

A force acts by pushes and pulls.

 

What Are Forces in Physics?

Physics defines force as a push or a pull. There are many kinds of forces but they all act by pushing of pulling to move an object.

Can you think of some other kinds of force?

Gravity is one. It pulls objects down to the ground.

Magnets have force. They can be used to push or pull each other around.

Electricity especially static is a force. Think about what happens when you rub a balloon and touch it to a wall.

For the next fourteen physics projects we will look at physical forces, pushing and pulling and how we can use this through simple machines to make work easier.

OS11 Floating Hot Water on Cold Water

If you pour water into water, it mixes up and has more volume. That is what usually happens. But if you are really up to the challenge, you can make hot water sit on top of cold water.

jar of hot water, jar of cold water

Question: How can hot water be made to sit on cold water?

Materials:

3 Jars

Water

Ice

Food coloring

Microwave or stove

Eye dropper

Procedure:

Half fill a jar with water

Add ice until some ice remains floating in the water

Half fill another jar with water

Heat this water close to boiling in the microwave (use a pan on the stove)

Add a drop of food coloring

food coloring in hot water

Sometimes, when you heat water on the stove, you can look down into the pan and see the water moving. These currents are in the jar of hot water and carry the food coloring around.

How does the food coloring spread through this water?

Stir to finish mixing the coloring into the water

Half fill a jar with ice cold water with no ice in it

This is the hard part: You will use the eye dropper to add the hot water to the jar of cold water. Do this by sliding the water down the side of the jar. Continue adding water until the hot layer is 1.5 cm thick.

hot water on cold water

The hot water tries to stay up on top of the cold water. Right underneath the hot water is an area cooling off with a layer warming up so some of the food coloring goes down into these layers creating the lighter colored layer.

Observe the hot water layer every fifteen minutes for an hour

Observations:

Describe how the food coloring moves through the hot water

Describe what the hot water layer does

At the start

In fifteen minutes

hot water mixing with cold water

Cold water has currents in it like the hot water does. That lowest layer of food coloring is getting pulled into these currents.

In thirty minutes

In forty-five minutes

In an hour

Conclusions:

Note: Density is how much stuff is in a certain volume. Something with less density will float on top of something less dense.

Is hot water more or less dense than cold water? Why do you think so?

Is this difference very much? Why do you think so?

What happens to the temperature of the hot water over the hour?

What will happen to the density of the hot water over the hour?

What will happen to the food coloring over time? Why do you think so?

food coloring is mixed

The hot water cools off. The cold water warms up. The water currents carry the food coloring around until all of the water turns blue. Some of the currents are still visible in the center.

What I Found Out:

The drop of food coloring split into many long streamers in the hot water. They slowly moved around the jar as they sank toward the bottom. The streamers spread out through the water.
The drops of hot water went into the cold water a little bit then rose to the top. The layer of hot water spread across the cold water. The color was darker on the top of the hot water layer.
I stopped adding hot water when my layer was 1.5 cm thick. Gradually a layer of lighter blue water spread under the hot layer. It got almost as thick as the hot layer started out. Streamers sank toward the bottom. A center core of blue went from the hot layer to the bottom. Then the blue spread all through the water.
The hot water must be less dense than the cold water because it stays on top. The densities must be very similar because I had to be so careful not to mix them when I put the hot water in and a layer at the edge does mix a little.
As the jar sits on the table, the hot water cools off. The cold water warms up. As they get closer together in temperature, their densities get closer and the hot and cold water mix. Then the food coloring will spread throughout the water.

OS10 Water Balloon Pressure

 

Water shot out of a hole in a can in an arc to the ground. The greater the water pressure behind the hole, the longer the arc. As the pressure fell, the arc shrank. Shouldn’t a hole in a water balloon act the same way?

filling the water balloon

Question: What happens to water coming out of a hole in a water balloon?

Materials:

Balloon

Pin

Water faucet in a large sink or hose

Block to set the water balloon on

Procedure:

Blow the balloon up about half way

Hold the neck closed and push on the balloon

How does the air behave?

hole in water balloon

It is easier to put a single hole in a partially blown up balloon. If the balloon is blown up too much, it will break.

Make a pin hole about half way down the balloon

Let the air go out of the hole

How does the balloon change as the air goes out?

Slide the neck of the balloon over the end of the faucet or hose [wetting it first makes this easier]

water balloon on faudet

Even if the mouth of the balloon is tight on the faucet, hold it on as you put water in the balloon.

Place the block so the balloon will sit on it as it fills up

Turn the water on slowly to fill the balloon

How does the water come out through the hole?

What happens to the hole?

Turn the water off when the balloon is about two thirds full

Observe how the water and the balloon act as the water goes out of the water balloon

Warning: Do NOT take the balloon off the faucet until almost all of the water is out of it‼!

Observations:

How does air behave

When you push on an air filled balloon

When the air comes out of a hole in the balloon

Describe how water acts as you fill the water balloon

water balloon filling

Like the water from the hole in the can, water arcs out of the hole in the balloon

Describe what happens to the hole

Describe what happens as the water balloon empties

Describe what happens to the balloon as it fills and empties

Conclusions:

Why does putting pressure on one part of an air filled balloon make another part bulge?

What happens to the balloon as you put pressure inside of it?

Why does the water arc get thicker as more water goes into the balloon?

water balloon with long water arc

The balloon stretches out and has elastic energy adding pressure to the water in the balloon making the water arc much bigger than the one from the can.

Compare the water arcs from the cans to the one from the balloon.

Why does the water arc from the balloon last so long?

 

What I Found Out:

I had some big round balloons. It was easy to blow one up just a little and poke a pin hole in it.

The balloon fit on the faucet in my bathroom sink tightly. I turned the water on a little.

For a few seconds water dripped out of the hole and ran down the balloon. After that the water arced out of the balloon. The balloon got bigger and so did the arc. Then both stopped changing.

I turned the water on a little harder. The balloon got a little bigger. The arc had more water in it but didn’t seem any bigger.

A balloon stretches as it gets bigger. A letter written on a balloon gets bigger as a balloon gets bigger. The hole got bigger so more water could get out.

I turned the water on a little more. The balloon got bigger slowly. The arc straightened out and had more water in it.

water balloon emptying

Taking the mouth of the balloon off the faucet before the balloon is empty lets the water form a geyser out of the mouth. This is only fun if you are outside on a hot day.

My sink was far too small. When the balloon got about eight inches across, the arc shot out over the sink and onto the floor.

When the water ran out of the can, the arc quickly shrank. The arc of water out of the balloon stayed up for a long time.

When I was done, I took the balloon off the faucet. Water shot up out of the mouth of the balloon like a geyser.

Only air and gravity put pressure on the water arcing out of the can. The balloon put pressure on the water inside of it making the arc large for a longer time and shooting the water out of the mouth when I took it off the faucet.

OS9 Changing Water Pressure

A column of water presses down on its base. Each cubic centimeter adds another gram of mass changing water pressure on the base. We saw how that works last week.

When the siphon moved water from one jar to another, the water ran slower as the jars were closer in height or the water level went down in the jar.

If you put a hole in a can, any water in the can will run out. What if there is more than one hole in the can? How will this affect how the water runs out of the can?

materials for project

Question: How does changing water pressure affect how water flows?

Materials:

2 very large juice cans with the top removed or soda bottles with the tops cut off

1 soup can or jar to set the large cans or bottles on

Large tray [not needed if you do this outside]

Drill with a 1/8 inch bit [Help to drill some holes in the cans]

Ruler

Tape

4 Nickels

Procedure:

Drill three holes 0.5 cm from the bottom of one juice can or soda bottle spaced around the can

bottom holes in can

It is possible to use a nail if there is a tight board inside the can. Drilling a hole is much easier and makes a better hole.

Use the ruler to make a line down one side of the other can or soda bottle

Mark a point 0.5cm from the bottom, 5.5 cm up, 10.5 cm and 15.5 cm

line of holes in can

The line of holes is supposed to be straight. Mine wavered a little as the drill slipped a bit on the can.

Drill holes at each mark

Put pieces of tape over the holes in the cans. Be sure these are tight.

tape over the holes

The piece of tape needs to be tight over the hole. The ends are left loose for easy grabbing.

Put the can with three holes on the small can in the tray, a bathtub or ground outside

Fill the can with water to the top or a mark so you can fill the can the same each time

how does changing water pressure affect water streams?

The can set well on the upside down jar. I didn’t get it put back exactly the same every time but couldn’t be too far off or the can would fall off. I filled the can to the rim each time.

Pull off one piece of tape and put a nickel where the water first hits the tray or ground

Measure how far the water went from the can

Changing water pressure made the stream start here then move in toward the can

I measured from the jar each time as the centimeters started a little out on the ruler accounting for the overhang of the can.

Describe how the water stream acts as the can empties

Take off all the tape from the holes and dry the outside of the can thoroughly

Put one piece of tape over all three holes

Will more than one hole make changing water pressure change the flow?

Masking tape will not stick to a wet can. Again the ends are loose for easy grabbing. Each part over a hole is rubbed down tightly.

Set the can back on the prop can and fill it with water to the same place as before.

Pull the tape off quickly and put a nickel where one of the streams of water hits the tray or ground

Observe how the three streams of water act as the can empties out

Measure how far the water went from the can

Set this can aside and put pieces of tape over the holes

Put the other can on the prop can

four holes taped on can

If each tape is on tightly on a dry surface, the pieces will hold even through refilling.

Fill the can with water

Pull off the top tape piece and put a nickel where the water first hits the tray or ground

Measure how far the water went

Dry the outside of the can and replace the piece of tape

Fill the can

Pull the tape from the second hole down and put a nickel where the water first hits

Measure how far the water goes

Dry the outside of the can and replace the piece of tape

Fill the can with water

Pull the tape from the third hole down and put a nickel where the water first hits

Changing water pressure measures this stream

This can behaved differently as the third hole stream went as far as the bottom hole in the first can.

Measure how far the water goes

Dry the outside of the can and replace the piece of tape

Fill the can with water

Pull the bottom piece of tape and put a nickel where the water first hits

Measure how far the water goes

Remove the pieces of tape and dry the outside of the can

four holes taped up

It helps to hold the top of the can steady while pulling off the piece of tape.

Put one piece of tape covering all the holes

Set the can on the prop can

Fill the can with water

Pull the tape off quickly and place nickels where each stream of water hits the ground

[You may have to do this more than once to mark all the streams of water.]

Observe how the streams of water act

Measure how far the water goes for each hole

Observations:

1st can:

Distance the water goes with one hole open

changing water level is changing water pressure

Opening one hole on the bottom let the stream of water go out 26 cm. It stayed that far for a time as the water level dropped then slowly moved closer to the can until it finally dribbled out as the water level reached the hole.

How the water acts as the can empties

Distance the water goes with all three holes open

How the water acts as the can empties

2nd can:

Distance for top hole

How the water stream acts as the can empties

Distance for top hole with all holes open

Distance for second hole

changing water pressure works until the level drops to the hole

Each time the stream of water is the longest at first and ends when the water level is the same as the hole.

How the water stream acts as the can empties

Distance for second hole with all holes open

Distance for third hole

How the water stream acts as the can empties

Distance for third hole with all holes open

marking with nickels

Nickels work well for marking the distances. They are easy to see. They are heavy enough the water stream can’t wash them away.

Distance for fourth hole

How the water stream acts as the can empties

Distance for fourth hole with all holes open

How the water acts as the can empties

Conclusions:

For the first can, compare how the water stream with one hole open acts with how the three act with all the holes open.

three holes makes changing water pressure faster

The three streams went out a shorter distance than for a single hole. The water level l was the same over all three but the water had more than one way to go so less went out each hole.

For the first can, is the water pressure the same for all the holes? Why do you think so?

Is the rate of changing water pressure the same for all the holes? Why do you think so?

For the second can, is the water pressure the same for all the holes? Why do you think so?

Is the rate of changing water pressure the same for all the holes? Why do you think so?

Does where a hole is placed in a container affect how water empties out of the container?

changing water pressure changes distances

All four distances were a little less than for single holes.

For the second can, compare how the water stream for the third hole acts with only that hole open to when all the holes are open.

Describe the changing water pressure as a can empties out.

Use the changing water pressure to explain how the water streams act as a can empties.

Do you think changing the sizes of the holes would change how the can empties?

Do you think making the holes different sizes would change how the can empties?

[You can try this and compare your ideas with what happens.]

 

What I Found Out:

My holes were a little high around the can. I put the tapes pieces over the three holes, set the can up and filled it with water. One tape dripped a little.

I steadied the can with one hand and pulled one piece of tape off. The stream of water went out. I marked it. It stayed going that far for a long time then gradually moved in until it was a dribble down the side of the can.

It was hard to dry the can until I got a towel. Then the tape went over all three holes. This time I steadied the can and jerked the tape off. Three streams of water shot out.

I marked the distance for one stream but the streams moved in faster than the single stream did. The three were soon dribbled down the side of the can.

For the single stream the distance was 26 cm. The distance with all three streams going was 23 cm.

The three streams acted much the same as the single stream except for being a little shorter and losing distance much faster. Since all the holes were the same distance up from the bottom of the can and the water was as deep over all the holes, they had the same water pressure on them. That made the rate of changing water pressure the same for all of them because the water level dropped the same over all of them.

Having the holes lined up from top to bottom of the can made the water act differently for each hole. The top hole water stream went the shortest distance, only 16 cm. The water stream shortened to a dribble very quickly.

The hole next down put out a longer stream, 24.5 cm. This stream lasted longer too.

The third hole had an even longer stream, 26 cm, and lasted longer too.

The fourth hole had the longest stream, 29 cm, and lasted the longest too.

four holes show changing water pressure

The water level dropped very quickly with all four holes open. This made it hard to mark all four streams at one test.

The water streams acted the same as for the three holes. Changing water pressure caused the streams to get shorter until they dribbled as the water level dropped to the hole level.

These holes had different water pressure behind them as the water column over each was different.

When all four holes were opened up, the streams of water were shorter. The changing water pressure made the streams change distance quickly. I had to refill the can to get all of them marked.

Making all the holes larger would let the water out faster. I think the streams would be shorter too because making the hole at the end of a hose makes the water go farther.

If the holes were different sizes, the water would go out the larger holes faster so the changing water pressure would make the streams get shorter faster.

OS7 How A Siphon Works

Water runs uphill in a straw. Think about how you drank through a straw. First you pulled all the air out of the straw. Second the liquid replaced the air in the straw so you got a drink.

If a straw was open to the air, you couldn’t get a drink. You had to get and keep the air out of the straw.

What is a siphon? It is a long flexible tube used to move a liquid from one place to another.

Can a siphon make water run uphill like a straw can?

siphon moving water

Question: How does a siphon work?

Materials:

2 Gallon Jars, clear

3 – 4 feet of clear plastic tubing (At least ¼ in. diameter, ½ in. is better)

1 ½ gallon water (Add a drop of food coloring to make it easier to see.)

Large measuring cup

Large pan or bowl to set a jar in in case the water spills

Chair or steps as high as a gallon jar

Note: It is easy to spill water in this project so working outside is a good idea.

Procedure:

Hold both ends of the tubing in one hand

Pour in water to half fill the tubing

Hold an end in each hand

Lift one end of the tubing and see what the water does (be careful not to spill)

Lower that end and lift the other end

Lower that end so the ends are even

Hold a thumb or finger over one end of the tubing

Lift one end of the tubing and observe the water

Lift the other end and observe the water

Even the ends of the tubing and block both ends with your thumbs or fingers

Lift one end of the tubing and observe the water

Lift the other end and observe the water

Fill one gallon jar almost full with water

Set the jar on the step or chair

empty siphon tube

The siphon tube is full of air when it’s put into the jars. The water can’t push the air out so no water flows through the tube.

Set the empty jar in the large pan on the floor next to the step or chair

Put the tubing into the empty jar

Pull enough tubing out to put into the jar of water all the way to the bottom

Observe what the water does

Take the tubing out of the water

Hold both ends of the tubing and pour water into it until the tubing is full

siphon moves water from high to low jar

Once the air is out of the siphon tube, water runs quickly from the full jar into the empty jar.

Close off one end tightly with a thumb

Put the open end back into the empty jar

Put the closed end into the jar of water half way to the bottom

Release the end of the tubing and push it to the bottom of the jar

Observe what the water does

siphoning water from lower step

Especially when the full jar is on the low step, the siphon loop rises high above the jars. Yet the water still flows from the top jar into the bottom jar.

Pulling some of the tubing up from the bottom jar, make the loop between the two jars higher until the tubing only goes to the bottom of each jar

Observe what the water does

If the top jar is empty, switch the jars and start again

Put the full jar on a lower step or chair and do this again

Observe what the water does

siphon works for two jars on the ground

It’s easy to see why water would move from a jar set higher than the lower jar yet water still moves from the full jar to the empty one when both are on the ground.

Put the two jars on the same level and start again

Observe what the water does

Observations:

Describe what the water in the tube does

With both ends open

With one end open

With both ends blocked

Describe what happens with the siphon tube

When put into the jars filled with air

When put in the jars filled with water

Describe what happens when the loop is lifted up

Describe how the siphon works with the jars closer together in height

When the siphon starts

When the loop is lifted

Describe what happens when the jars are beside each other

When the siphon starts

When the loop is lifted

Conclusions:

When both ends of the tubing are open, what can go in and out of the tubing besides water?

Is this still true when you block one or both ends?

How does this change how the water acts?

Why do you close one end of the filled tubing to put it into the jar of water?

Why does water move through the tubing from the full to the empty jar when it is filled with water but not when it is filled with air?

How does the movement of water change as the height of the loop changes?

Can the loop be too high for the water to keep moving?

How does the height difference between the jars affect how the water moves?

What causes the water to move from one jar to the other? Is this the same as how water comes up a straw?

Does water really move uphill by itself? Why do you think so?

siphon almost done

The siphon continues to move water as long as the water is higher than the bottom jar until the level is so low air gets into the tube.

What I Found Out:

Making the water blue really helped me to see where the water was in the tube. I put enough in to half fill the tube.
When both ends of the tube were open, the water moved up and down as I moved the ends of the tube. The two surfaces stayed level no matter how fast or slowly I moved the tube ends.
Blocking one end of the tube changed things. The water moved only a little ways toward that end then stopped. When I lifted the blocked end up, the water didn’t move down very far until bubbles of air started moving up into that end.
Once both ends were blocked, air bubbles had to move from one end to the other to make the water levels change.
Air controls the water levels in the tube. When an end is not blocked, air can move in and out easily. Blocking one or both ends keeps the air at that level unless the open end is low enough for more air to move into the blocked end.
I used a step stool with two steps on it to set my jars on. The first time I set the full jar on the top step and the empty jar on the ground. One end of the tube went in the top jar. The other end went in the bottom jar. Nothing happened.
Leaving the two jars where they were, I took the tube out and poured water in it until it was full. Blocking one end keeps air from getting into the tube to push the water out. If the end in the lower end is open, air can bubble up into the tube before the other end gets into the top jar.
When the tube is full of air, the water doesn’t get pulled in just like when the one straw was outside the glass. A straw only works when all the air is pulled out. Having the tube full lets gravity pull the water down from the full jar to the empty jar. It works like a siphon. Raising the loop doesn’t stop the water from moving. It can slow the water down especially when the two jars were both on the ground.
The water moved differently when the top jar was placed on the different levels. Using the top step let the water move fast from the full to the empty jar. The top jar had only a little water left in it when air got into the tube and pushed the water out of the tube.
Using the lower step slowed the water down. It still moved from the top to the bottom jar, just not as fast. The top jar ended up almost empty at the end.

siphon stops when water levels are equal

When both jars are on the ground, the siphon stops working when the water levels in both jars are the same leaving the tube filled with water.

Placing both jars on the ground changed everything. The water moved very slowly from the full jar to the empty one until the water level was the same in both. then it stopped. The tube was still full of water but it did not move. The water only moved when one jar had more water in it than the other, then ran downhill in a way to level it up.
Water does not move uphill on its own. It can appear to do so through the siphon loop but it is really ending up lower than at the beginning.

OS6 Solving Straw Power

Water goes downhill because of gravity. Water defies gravity going up a straw. How?

2 straws and a jar of liquid are needed

 

Question: How does a straw work?
Materials:
2 clear straws
Clear glass of liquid (can be colored)
Procedure:
Put a finger over the end of a straw
Put the other end in the glass of liquid against the side of the glass

Blocking the end of a straw keeps liquids out

It’s hard to see but only a little bulge of liquid is at the bottom of the straw while the top is covered with a finger.

Observe what happens
Take your finger off the end of the straw
Observe what happens
Put your finger over the end of the straw and lift it out of the glass

straw lifted up full of liquid

Keeping the end of the straw blocked with a finger lets the column of liquid get lifted out.

Observe what the liquid does
Take your finger off the end of the straw (Hold it over the glass!)
Observe what the liquid does
Take a drink through the straw

Sarah drinking through 1 straw

Sarah finds drinking with one straw is easy. She pulls all the air out of the straw and juice rushes up fill he space.

Observe how you do this, how your mouth works
Put the second straw in the glass of liquid
Take a drink through both straws at once
Observe how you do this, how your mouth works
Take one of the straws out of the glass so one ends in teh glass and one out of the glass
Take a drink through both straws at once
Observe how you do this, how your mouth works
Observations:
Describe what was in the straw when your finger is on the top
Describe what is in the straw after removing your finger

straw full of liquid

When the straw is not blocked, liquid fills it up to the same level as in the glass.

Describe what the liquid does when you lift the straw
Describe what the liquid does when you remove your finger
Describe how you use a straw to take a drink

Srarh drinking through 2 straws

Two straws let Sarah drink her juice faster.

Describe how you use both straws to take a drink
Describe taking a drink with one straw in the glass, one out of the glass
Conclusions:
Why doesn’t liquid go into the straw when the top is blocked?
What happens when you take your finger off the straw?

Air pushes the water out of the straw

Holding the filled straw over the table and taking the finger off is a way to make a big mess. Air rushes in and pushes the water out.

Why doesn’t air keep you from taking a drink with a straw?
Why can’t you take a drink through two straws when one is outside the glass?

What I Found Out:

I found two large diameter straws to use. For the first parts of the project I used water with a little blue food coloring. One drop was too much and I kept diluting itt until the water was light blue.

First I held a finger on the top of the straw and pushed it into the water. No water went into it. A small bulge was visible at the bottom.

Air filled the tube. When my finger was on top and water on the bottom, the air couldn’t go in or out. It kept the water out as there wasn’t room for both. As soon as the air could get out, it did letting the water fill the tube.

As soon as I took my finger off the top, water rushed in so the level inside and outside of the straw was the same. I put my finger back on top and lifted it out of the water. The water inside lifted up too and didn’t fall out until I took my finger off the top.

This time the water was trapped inside and kept the air out. Once air could get inside, the water left.

My friend Sarah Brown helped me with the rest of the project as it is difficult to drink through a straw and take pictures of me doing it at the same time.

When Sarah used one straw, she pulled all the air out of it and juice rushed in to fill it up. Two straws worked the same way only doubling the amount of juice Sarah could drink.

Sarah is trying to get a drink of juice. Air rushes in the straw on the outside replacing all the air she pulls out of the other straw so the juice can't get into the straw.

Sarah is trying to get a drink of juice. Air rushes in the straw on the outside replacing all the air she pulls out of the other straw so the juice can’t get into the straw.

Everything changed when one straw was in the juice and one was outside the glass. Now Sarah tried to pull all the air out of the straw but more air kept coming back. No juice would get pulled up.

OS5 Float a Jar

Some things float. Some things sink. Some are in between. Why?

Often heavier things sink and lighter ones float. Can mass be the reason?

materials to do project

Question: Why do some things float and others sink?

Materials:

Big bucket of water

Small jar with lid

Scale

Procedure:

Put the lid on the jar tightly

Measure the jar’s height and diameter in centimeters

massing the jar

Mass the empty jar in grams.

Mass the jar in grams

Float the jar in the bucket of water

float the empty jar

The empty jar floats high in the bucket of water.

Take the jar out of the water

Pour about 1.5 cm water into the jar

Put the lid on tightly

Mass the jar and water

mass the jar and water

Each addition of water increases the mass of the jar and increases its density.

Float the jar in the water

Describe how well the jar floats

Add another 1.5 cm water to the jar, mass it and float it

Continue to do this until the jar sinks

Observations:

Jar measurements:

Height:

Diameter ( biggest distance across)

Masses:

Empty jar:

How well it floated

Jar with 1.5 cm water:

How well it floated

float the jar and water

The water in the jar tends to push the bottom into the water. It definitely doesn’t float as well as the empty jar.

Jar with 3 cm water:

How well it floated

Jar with 4.5 cm water

How well it floated

Jar with 6 cm water:

How well it floated

Jar with 7.5 cm water:

How well it floated

Jar with 9 cm water:

How well it floated

Analysis:
Calculate the volume of the jar (volume = πrrh where π is 3.14, r is half the diameter and squared, h is height)
Density is how much stuff is in a certain space. Calculate the density of the empty jar by dividing its mass by its volume. The units will be grams/cc or cubic centimeter.
Calculate the density of the jar with each addition of water.
There is another way you can use if your jar is not very square like mine with the top and bottom tapering. Fill your jar to the very brim with water and put the lid on tightly. Mass it. Subtract the mass of the empty jar. Water is supposed to have 1 gram equal to 1 cc so the answer should be close to the volume of the jar.
Conclusions:
Water has a density of 1 g/1 cc.
Compare the density of each water level of jar to the density of water to how well the jar floated.
Does density show when something will float or sink? Why do you think so?
A ship is made of iron, a very heavy metal but floats. Why does the ship float?

What I Found Out:
My jar had a diameter of 6.8 cm so the radius was 3.4 cm and a height of 12 cm. This gave it a volume of 435.6 cc.
When I filled it with water and massed it, the mass was 736.5 g. The empty jar was 251.7 g so the volume by that method was 484.8 g or cc.
Since my jar had a mass of 251.7 g, the empty jar had a density of 0.6 g/cc. The jar floated on top of the water.
I did not measure the water very carefully but the mass was the important thing.
After adding the first amount of water, the mass went up to 332.9 g and the density went to 0.8 g/cc. The jar still floated sideways and high.

Each jar does float but lower in the water and upright

The jar floats upright so the water in the bucket is a little over the water level inside the jar.

The second amount of water increased the mass to 406.1 g raising the density to 0.9 g/cc. The jar still floated but with the bottom angled down into the water.
The third amount of water increased the mass to 443.6 g raising the density to 1.0 g/cc. The jar now floated upright in the water with most of the jar under water.
The fourth amount of water increased the mass to 482.4 g raising the density to 1.1 g/cc. The jar still floated but was much lower in the water.
The fifth amount of water increased the mass to 546.6 g raising the density to 1.3 g/cc.. The jar floated but only the lid was still above water.
The sixth amount of water increased the mass to 595.4 g raising the density to 1.4 g/cc. Now only the very top of the lid was above the water.
The seventh amount of water had a mass of 631.7 g raising the density to 1.5 g/cc. The jar sank immediately to the bottom of the bucket.
If I used the volume from filling the jar with water, the densities were less. They were: empty 0.5 g/cc; 1st 0.7 g/cc; 2nd 0.8 g/cc; 3rd 0.9 g/cc; 4th 1.0 g/cc; 5th 1.1 g/cc; 6th 1.2 g/cc; and 7th 1.3 g/cc.
When the jar floated each time, the water level outside was a little higher than on the inside. This difference increased a little each time.

almost full jar does not float

When the density is a little more than the density of water, the jar sinks.

The jar barely floated once the density of the jar was the same as the density of water. The density didn’t need to be much more than that of water before the jar sank.
For the jar density does seem to match to how well the jar floated. This might have been more striking if I had a more precise volume for my jar. I think density determines whether the jar sinks or floats because the jar floated with the air part above water and the full part below until the density got too much and it sank.
Ships work the same way. They have big rooms filled with air to make the ship’s density less than the density of water. This makes them work just like the jar.

OS4 Water Surface

Do you know what a water strider is? Perhaps you’ve seen one or a group of them skating across the surface of a pond. Why don’t they sink?

water striders skate on the water surface

Water striders prefer quiet areas of streams and ponds. They scavenge food like drowned insects floating on the water surface as the striders appear to skate their way along.

The reason water striders can walk on water is one of the special things about water. Every liquid has a place where the liquid stops and the air begins but the water surface is tough.

penny on paper towel

Question: What is special about the water surface?

Materials:

Measuring cup with 2 cups of water

Paper towels

Penny

Eye dropper

Bowl

Needle

Jar

Dish soap

 

Procedure:

Fold a paper towel in half and put it on the table

Put a penny in the center of the paper towel

Predict how many drops of water you think can be put onto a penny before they run off

Put 1 drop of water on the penny

single drop of water shows water surface shape

A single drop of water on a penny doesn’t spread out. It holds together in a tight high half sphere because of water surface tension.

Observe and describe the shape of the drop

Use the eyedropper to put water, one drop at a time, on the penny

Remember to count how many drops of water you put on the penny

tight water surface tension keeps 10 drops contained

The water holds together under that water surface so tightly that even ten drops doesn’t cover the entire penny.

Stop every 10 drops to observe the shape of the water on the penny

Continue adding drops of water until the water runs off the penny onto the paper towel

Dry off the penny and set it aside

Discard the paper towel

Pour water into the bowl until it is half full

Take the needle and carefully set it flat on the surface of the water in the bowl

water surface holds up needle

A needle is a flat piece of metal but it still sits on top of the water surface.

Describe the surface of the water around the needle

Take the needle out of the bowl, dry it and set it aside

Pour the water back into the measuring cup

Pour water into the jar until it is a third to half full

Describe the water surface in the jar

water surface forms meniscus

The meniscus is the reverse of the water drops with the lowest part in the center and the highest parts going around the edge.

Pour the water back into the measuring cup

Add 5 drops of dish soap to the water in the measuring cup

Fold a dry paper towel in half and set it on the table

Set the penny in the center of the paper towel

Predict how many drops of water will sit on the penny before it runs off

Put 1 drop of soapy water on the penny

soap changes water surface

A little soap changes the shape of a drop of water a lot as this drop on a penny shows. The water surface is no longer that high tight form but a flattened puddle.

Observe and describe the shape of the drop

Use the eye dropper to put drops of water, one at a time, on the penny

Remember to count the number of drops

Stop every ten drops and observe the shape of the water surface on the penny

Continue adding drops until the water runs off onto the paper towel

Clean up the paper towel and penny

Pour soapy water in the bowl until it is half full

Carefully place the needle flat on the surface of the water

Describe what happens

Take the needle out of the bowl

Pour the water back into the measuring cup

Pour water into the jar until it is a third to half full

Describe the water surface in the jar

Clean up

Observations:

Prediction of drops of water on a penny:

Number of drops of water you put on the penny

Descriptions of the water surface on the penny

round water surface makes penny look like a dome

Twenty drops of water make a penny look like a dome with the rounded water surface.

Description of the water surface around the needle

Description of water surface in the jar:

Prediction of drops of soapy water on a penny:

Number of drops of soapy water you put on the penny:

Descriptions of the soapy water surface on the penny:

Description of what happens placing a needle on soapy water:

Description of the soapy water surface in the jar

Conclusions:

What do you think the water surface is doing as the drops pile up on the penny?

Does this explain why the needle can sit on the water in the bowl?

Does this explain why a water strider can walk on water?

Why can’t a cat or dog walk on water?

soapy water meniscus

In the jar water still has a small meniscus but much less than the plain water had.

Compare the meniscus or dip on the surface of the water in the jar of plain water and soapy water.

What does the soap seem to do to the water’s ability to make this surface layer?

water surface is flattened with soapy water

Ten drops of plain water didn’t touch the edges of the penny but ten drops of soapy water do.

Could a water strider walk on soapy water?

 

What I Found Out

After setting up the penny I put one drop of water on the center. The drop didn’t spread out. It stayed in a high found half sphere.

I thought I could put 25 drops of water on the penny before it ran off onto the paper towel. This was much less than the 36 that did sit on the penny.

Ten drops later the water didn’t even touch the edge of the penny. The water stayed in the high round half sphere.

Twenty drops later the water finally touched the edges of the penny. The water was still in that high round half sphere. The water seemed to hold itself together like it had a skin on it to hold the liquid inside.

water surface bulges with 30 drops of water

Thirty drops of water bulge upward and outward on the penny.

The half sphere kept getting higher until 30 drops of water were piled on the penny. Drop 36 finally made the water run off the penny.

My needle floated on top of the water. The surface of the water seemed to make a dip around it. It was like the skin on the surface of the water molded itself around the needle.

This water skin on the surface would hold up a water strider or other small insect. A large insect or animal like a cat would be too heavy breaking the skin and sinking.

The water in the jar was lower in the center than around the edges. The edges seemed to almost climb up the jar.

Since so many drops of water sat on the penny, I thought at least 30 drops of soapy water would sit on the penny. This was far too many as only 22 drops did.

The first drop looked a lot different sitting on the penny. The drop was more spread out and not as high.

Ten drops of soapy water didn’t quite go to the edges of the penny but took up more room than the plain water had as it was wider and not as tall.

twenty drops of soapy water on penny

Twenty drops of soapy water barely stay on top of the penny.

Fifteen drops of soapy water went to the edges of the penny. The next six drops made the water taller but it was flatter than the plain water. Drop 22 made the soapy water run off onto the paper towel.

When I tried to put the needle on the surface of the soapy water, it sank immediately. I dried the needle and tried again but the needle would not float on the soapy water.

The dip in the water in the jar was less. Water didn’t seem to try to climb up the sides like the plain water did.

The soap seems to stop the skin from forming on the water surface. Without that skin to stand on, a water strider would sink just like the needle did.

 

About Water Molecules and Surface Tension

We know now that everything is made up of atoms and molecules. Water molecules have two hydrogen atoms attached to an oxygen atom.

These three atoms don’t line up flat. Instead they form an angle with the oxygen atom at the point.

This lets the water molecules line up ≪≪≪≪<. The oxygen atom likes the hydrogen atoms near it so they hang onto each other. This is especially true at the water surface.

The surface becomes very tough, for molecules and is called surface tension. It lets the water surface curve and climb up the side of a jar a little ways. It lets insects like water striders walk on it.

Soap breaks up this lining up of water molecules. They can’t hang onto each other any more. The surface tension gets weak so even a water strider will break through.

 

OS3 Volume of Water

Volume is a measure of how much stuff is in so much space. This is a special kind of space.

A line goes between two points or places. You can’t put much stuff into a line.

When you have several lines joined together, you have a shape. You can put stuff into the space between the lines but only one layer deep.

If you have a lot of the same shapes piled up on top of each other, you can put lots of stuff inside the space inside. Volume has three parts: length, width and depth.

In chemistry the basic volume has a length of 1 cm, a width of 1 cm and a depth of 1 cm. The amount of space is 1cm x 1 cm x 1 cm or 1 cm3 or 1cc [cubic centimeter].

For gases this basic measure is increased to 1 cubic meter. We can see why by comparing how water volume and air volume behave.

materials to explore water volume

Question: How do water volume and air volume compare?

Materials:

1 or 2 syringes holding 12 cc to 20 cc

Note: You can probably get these from a veterinarian. You do not need needles.

Tape

10 cm length of aquarium or other soft plastic tubing that fits tightly on the syringe

Paper

Custard cup of water

Procedure:

Note: If you have only one syringe, do everything with the air, then do everything with the water.

Pull the plunger back on one syringe to the highest mark to fill it with air

Record how much air is in the syringe

Put a piece of tape over the open end and fold it around the end to seal the syringe.

Hold a finger over the tape on the end and push down on the plunger until it stops

Record the reading of air in the syringe

Put the end of the other syringe in the water and pull back on the plunger a little ways

There will be air in the syringe so turn the end straight up and push down on the plunger until the air is out

Now fill the syringe to the same mark as the air

testing the volume of water

Water is drawn up into a syringe which is sealed up. Can you push on the plunger and make the water take up less volume?

Record the amount of water in the syringe

Dry the end of the syringe and tape it closed

Hold a finger over the taped end and push down on the plunger until you can’t push it down any more

Record the amount

Push the end of the tubing onto the end of the syringe

Tape the tubing tightly onto the syringe so it will not leak

Pull the plunger back filling the syringe with air to the same mark as before

Record the amount

Make a paper plug to push into the open end of the tubing

volume of air

The paper plug seems to fill the end of the tubing. It is tight, as tight as I could make it. Will it stop the air from escaping?

Note: I make this paper plug by taking a small piece of paper about 20 cm square. I push down on the center and twist the outer part around tightly to make a cone. The end of the cone is pushed into the tubing then twisted in until I can’t get any more of the plug into the tubing.

Slowly push the plunger down observing how the volume changes and the plug acts

Pull the plug out of the tubing

Put the end of the tubing into the cup of water and half fill the syringe

Hold the end of the tubing straight up and pull all the water into the syringe

Push down on the plunger enough to push all the air out

Put the tubing back in the cup of water and fill the syringe to the same mark as before

Record the amount

Make a new paper plug and push it into the end of the tubing

Note: For this last part it is a good idea to go outside or inside a shower stall.

Slowly push down on the plunger observing how the volume changes and the plug acts

Observations:

Volume of air

Starting:

Ending:

How it feels pushing the plunger down:

Volume of water

Starting:

Ending:

How it feels pushing the plunger down:

Amount of air in tubing

Starting:

Ending:

How the volume and plug act:

Amount of water in tubing

Starting:

Ending:

How the volume and plug act:

Conclusions:

Did the amount of air in the syringe change or only the volume? Why do you think so?

Did the amount of water in the syringe change? Did the water volume change? Why do you think so?

Does air have a definite, unchanging volume? Why do you think so?

Does water have a definite, unchanging volume? Why do you think so?

How does this explain the changes in height you saw in the last Project?

Tractors and other big machines have fluid filled tubes to lift buckets and other parts. Pressure is put on the fluid at one end of the tube to move things on the other end. Why do they use fluid and not air? [This is called hydraulics.]

 

What I Found Out:

I had one 12 cc syringe so I did everything with air first. The first step was to pull air into the syringe and tape the end.

My syringe held 10 cc of air. When I held the tape on the end and pushed the plunger, it moved quickly to start with. Then it got harder and harder to push down until it stopped. The syringe now read 3 cc.

The amount of air in the syringe stayed the same but the volume didn’t because I could push the plunger down. Air has no definite volume and can be compressed or stretched out.

Next I taped the tubing on the syringe. I held the end firmly closed and pushed down on the plunger. this time it went down to 5 cc but crept back up to 6 cc when I quit pushing down.

I made a paper plug and pushed it into the end of the tubing. I thought this was very tight but, when I pushed down on the plunger, it went down all the way as the air leaked out around the paper plug.

After taking the tubing off the syringe, I filled it with 10 cc of water and taped the end. This time, when I pushed the plunger, the plunger would not move at all. The 10 cc of water stayed 10 cc so water has a definite volume.

Since the water takes up the same volume in any container, it will have a greater depth in a narrow space and a lower height in a wide space. This is what happened in the last Project.

Next I put the tubing back on the syringe. I put water in the syringe until it read 10 cc. Holding the end of the tubing, I pushed on the plunger and it did not move as I expected.

I made another paper plug and pushed it into the end of the tubing as tightly as I could. When I pushed on the plunger a few drops of water oozed out. Then the plug shot out of the tubing and across the lab table.

Machinery uses fluid because it doesn’t change volume. When pressure is put on one end, the pressure pushes on the other end to lift a bucket or other part.

I read in “Xplor” magazine from the Missouri Department of Conservation that bugs like spiders use hydraulics to move their legs. It gives them lots of power so jumping spiders can jump long distances very quickly to catch their next meal.

If you don’t get “Xplor” – it’s free to Missouri residents – check it out on the Conservation Department website http://www.mdc.mo.gov and sign up for it and “The Conservationist.”

OS2 Changing Shape of Water

No matter what style of glass you pour water into, the water fits. You can pour water from a short fat glass into a tall skinny glass into a square glass. It still fits. Liquids like water are good at changing shape.

Changing shape is easy for water because it is a liquid. Water has no definite shape.

Does anything else change about water as it moves from one container to another?

materials needed for project about changing shape of water

Question: Does changing shape change anything else about water?

Materials:

Water

Tall skinny glass or jar

Short fat glass or jar

Square container

Scale

Ruler

Measuring cup

Procedure:

Mass the measuring cup

water in measuring cup

When measuring out water, remember it has a meniscus or dip in the surface. Water is measured to the bottom of the meniscus.

Pour 1 cup of water into the measuring cup and mass it

Mass the tall skinny glass

Massing tall skinny glass

The problem with using this glass is how hard it is to see through it. I want to redo this project with a clear glass once I find one.

Pour the cup of water into the glass and mass it

Measure how wide the inside of the glass is in centimeters

Measure how high the water goes in the glass in centimeters

massing short fat jar

The volume of this jar will not be quite right as the bottom is not squared off. It is close.

Mass the short fat glass

Pour the water into it and mass it

Measure how wide the inside of the glass is

Measure how high the water goes in the glass

Mass the square container

massing the square container

When measuring any container for the inside volume, you are measuring the inside. This can be harder to do but the thick walls of this container distort the water volume results by almost 80 cc.

Pour the water into this container and mass it

Measure the sides of the container

Measure how deep the water is in the container

Pour the water into the measuring cup and mass it

Observations:

Amount of water to start:

Amount of water at the end:

Mass of water to start:

Mass of water at the end:

When changing shape, does mass or volume change? table for observations

Analysis:

Subtract the mass of the empty container from the mass of the container of water to get the mass of water in the container.

changing shape of water from cup to jar

The height of the water in the short fat jar is much lower than in the tall skinny glass.

Volume of a cylinder like a glass is the diameter times pi (3.14) times the height.

Volume of a square is the length of a side times the length of a side times the height.

 

The width is the diameter of the glass. Use the height of the water. Multiply to calculate the volume of water in each container.

Conclusions:

Did the height of the water change in the different containers?

Did the width of the water change in the different containers?

Compare how the height and width change.

Did the mass of the water change in the different containers?

changing shape from round to square

Liquids like water change shape easily from round to square and back again.

Did the amount of water change as you poured it from one container to another?

How do you know?

What changes when water moves from one container to another?

What does not change when water moves from one container to another?

 

What I Found Out

I decided to measure out 250 ml of water. The water had a mass of 246 g.

When I poured the water into the tall glass, the height was 11 cm. The width was 5.4 cm so the water had a volume of 186.5 cc. The mass was still 246 g.

changing shape does not change mass or volume

Glasses are slightly tapered. Jars have rounded bottoms. Square containers have rounded corners. Each affects the volume calculations a little.

When I poured the water into the fat jar, the height was only 8.1 cm. the width increased to 7.3 cm so the water had a volume of 185.7 cc.

When I poured the water into the square container, the water was 1.8 cm deep. The container was 10.6 cm by 9.5 cm so the water had a volume of 181.3 cc.

The height of the water was different in the different containers. The skinnier the container, the deeper the water was.

The mass of the water stayed almost the same. It got a little less from the beginning to the end.

The volume of the water did go down a little as I poured it into each container but stayed much the same. Each container was wet inside so some of the water did not our into the next one.

The amount of water stayed the almost the same because the mass and volume stayed almost the same. The changing shape was the only change in the water.

OS1 Kinds of Water

Chemically all water has two hydrogen atoms attached to an oxygen atom. Since this is true, all water should be the same.

If this is true, why do companies bottle so many different kinds of water? Why do some people insist on using rain water to water some of their plants?

different kinds of water

Question: Are there really different kinds of water?

Materials:

At least three water samples from different sources

Water sources: different brands of bottled water, rain water, tap water, creek water

Collecting water samples: (bottled water is in a container) Use a glass jar with a lid. Label the jar with where the water came from.

3 glasses for each kind of water (You can use the same 3 for all the samples washing them in between but it will make the Project take much longer.)

Procedure:

Write down where each water sample came from

Label 3 glasses or custard cups for each sample

label the cups for the different kinds of water

I put the number on the jar label and on the cups. The quarter cup of water half filled these plastic cups.

Put 1/4 cup water in each cup (You will have 3 glasses of each sample kind.)

Put 1 glass of each kind of water in the refrigerator for 30 minutes

Take 1 glass out of the refrigerator

Note: Do NOT taste water from any source other than bottled water or tap water.

Write down what the cold water looks and smells like

If the water is bottled or tap water, taste the water by putting a small mouthful in your mouth and swishing it back and forth.

Write down what the water tastes like.

Get the glass of the same sample sitting on the counter

Write down what this sample looks, smells and tastes like

Put the third glass of this water sample in the microwave for 10 seconds

Write down what this sample looks, smells and tastes like

Repeat this with the glasses of other water samples

You can put 1/4 cup of each sample in a saucer or glass and set it out on the counter until the water evaporates.

Write down a description of any residue left behind in the container

Observations:

Write down where each water sample came from, the ingredients listed on the bottle, what the source looked like and where it is.

cups of different kinds of water

Each water sample has three cups. One cup spends half an hour in the refrigerator or maybe more. One sits on the table. The other goes in the microwave for 30 seconds. I tried fifteen and the water didn’t get hot.

Describe how each water sample looks, smells and tastes –

Cold:

Warm:

Hot:

Describe any residue left if you evaporated the water samples

Conclusions:

What color is water? Why do you think so?

What does water smell like? Why do you think so?

What does water taste like? why do you think so?

If you evaporated some water, was there anything in the water? What do you think this does to the water?

Does temperature change how different kinds of water smell and taste? Why do you think this happens?

Why can some people smell the rain? What are they really smelling?

What makes different kinds of water different?

Is all pure water the same?

 

What I Found Out

I didn’t smell any odor for any of my water samples. None of my samples had any color. All of my water samples felt wet.

Smell and taste differed in some of the water samples. The creek water had no smell when cold, a damp, musty smell when warm and a stronger musty smell when hot.

The rain barrel sample had no odor until it got hot. Then it smelled a little like when spinach is cooking.

Bottled water always tastes strange to me. It had a slightly dusty taste when cold that became a definite odd taste when the water was warm. Hot bottled water tastes like plastic.

The well water had a slight earthy taste when it was cold. The taste got stronger as the water got warmer.

The city tap water had a metallic taste. This too was slight when cold and got stronger as the water got warmer.

All of my water samples had no color so water must have no color. I did notice the rain barrel sample had a layer of green on the bottom. The green must be algae, tiny green plants.

None of my water samples had any odor so I think water has no odor. I have smelled odors in water before but the smells were from chemicals like chlorine or sulfur in the water, not the water itself.

The taste of water seems to be like the smell of water. The water itself has no taste. When the water does have a taste, it is from something in the water.

My water samples didn’t have time to evaporate yet. I will know more in a few days.

Temperature made a difference to tastes in the water. The colder the water, the less the taste.

I can smell the rain. It isn’t really the rain I smell, it’s things getting wet like hot, dry rocks or dirt.

Different kinds of water are different if they have different things in the water. The water itself is always the same with no color, odor or taste.

Meet The Water Project

Hot days invite people to play in the water. We go swimming, boating, water sliding and playing in the sprinkler.

What is this water? What makes it so special? The Water Project will take a look at this liquid so necessary to life on Earth.

Water Project: the meniscus

Why isn’t the surface of the water flat? The reason is one of water’s special properties.

What Is Water?

Chemically water is two atoms of hydrogen attached to an oxygen atom. The molecule is bent and has special electrical properties.

For life water is how we work. Our bodies are over 70% water. Watermelons are 90% water!

The special properties of water is why our bodies need that water for transporting all kinds of things, for doing chemical reactions and for staying cool.

The average person can survive close to a month without food. A week without water is deadly. In the desert that may shorten to a few hours!

The Water Project will explore some of the special chemical properties of water.

 

What Can Water Do?

We use water for lots of things. Transportation is one. Why does a boat float?

Water is used to operate machines. What properties of water make this possible?

Water is used to keep us and other things clean. Why can water do this so well?

Water can be very destructive. How can water move boulders?

Water Project: pressure

In the upper reaches the Meramec River is still small but powerful enough to create and destroy gravel bars. What makes water so strong?

Water in Nature

Of course water is found in creeks, rivers, ponds, lakes and oceans. It supports fish and many other creatures from single celled creatures to giant whales.

This summer’s Water Project will not be visiting any of this. There is not enough time. Perhaps next summer we can explore this part of water.

 

What Will Become of The Water Project?

Like last summer’s pumpkin projects, these too will be included in a science book. Already I am planning the stories about wells, waste water treatment, dowsing and more.

How many puzzles can I create about water? I don’t know – yet. Which kinds of puzzles did you like the best in The Pumpkin Project?

There aren’t too many recipes for water. Those I know of are great summer treats. Perhaps I will find a few more specialties.

Water Project: pressure

The water tower is a common site in many towns. Why are they built? How do they work?

Doing the Projects

Each week over June, July and the beginning of August there will be a project about some aspect of water. Some are simple and require very few materials. Others are more complex.

The first Project is up next week. Please join me for a summer of water fun.

The Pumpkin Project

OS1 Starting The Pumpkin Project

Why Investigate Pumpkins?

 Plants aren’t interesting. They’re dull. They don’t move. Once you’ve seen a leaf, a stem, a root and a flower, you’ve seen all there is to a plant.

Say that to the hundreds of people worldwide who grow giant pumpkins and they know you’ve never really taken a look at plants. Botanists (scientists who study plants) have studied plants for hundreds of years and are still finding out new things about them. This is your chance to find out a little bit of what all these people find so exciting.

Why pick pumpkins? There are lots of reasons. One is that the big seeds are easy to work with. Another is that pumpkin seeds are easy to find and grow. Still another is the huge number of different kinds of pumpkins.

And pumpkins are important commercial crops. They are eaten by people all over the world. They are grown on every continent except Antarctica.

mini pumpkin

Tiny pumpkins take only a little space to grow and will even grow in a pot. They make nice Halloween decorations.

Pumpkins are fun to grow. They can be used to make art. There are competitions for the largest pumpkins at county and state fairs. Then there are the competitions to grow giant pumpkins in North America, Europe and Australia. A newer competition for throwing pumpkins is starting around the United States.

When should you start investigating pumpkins? Some of the investigations use pumpkin plants. Since these grow best in warm weather, spring and summer may be the best time. But many of the investigations take a week or two to complete because seeds take time to germinate and grow. The best time to start learning about pumpkins and plants is now. Then you will be ready to grow your best pumpkins ever in Project 1.

Project 1

Part 1

Making Plans

 It should be easy to guess what the first big Project is in a book about pumpkins. Project 1 is growing a pumpkin!

Before you race to the store and buy some pumpkin seeds to grow, let’s make plans.

 What Kind of Pumpkin Should You Grow?

 By this time you have noticed there are lots of kinds of pumpkins. Some are very small. Others are extremely large. They come in different colors. Some have warts. Some have strange things on them.

Before you decide on the kind of pumpkin you must decide where your pumpkin will grow. The space needed is listed as square like 10 feet by 10 feet but it can be longer and narrower as 5 feet by 20 feet, just have that much room. The place must get at least half a day of sunlight.

 

pie pumpkin

Weighing five to seven pounds pie pumpkins are grown for eating. They are usually sweeter than larger pumpkins.

Small pumpkins need only a little space, even a big pot will do. They can grow on a trellis. If you have only a little place for your pumpkin plant, you should grow a little pumpkin.

Sugar pie pumpkins are a little bigger. These seven to ten pound pumpkins are the best kinds for eating. They need a space about ten feet square. They can grow on a trellis but you will have to support the pumpkins. The pumpkins may not get as big as they normally would because they will not get as much food.

Halloween sizes of pumpkins get ten to twenty-five pounds. These pumpkins can be eaten too. They are not as sweet as pie kinds and are stringier. These plants need a place twenty feet square.

Really big pumpkins need lots of room. Giant pumpkin plants need a place at least forty feet square. These plants need special care every day. They need lots of fertilizer and water. But growing one of these really big pumpkins is exciting.

 

Halloween pumpkin

Stores have lots of these pumpkins in October. This is a Halloween type pumpkin.

What Kind of Pumpkin Will You Grow?

 Once you know how much room your pumpkin plant will have, you can pick a kind to grow. Mini pumpkins come in orange, white and two colors. Pie pumpkins come in colors too but it is hard to tell when a white pumpkin is really ripe. Bigger pumpkins have even more choices. Pick out your favorite pumpkin of that size. That is the one you will grow.

 Getting Ready

 Serious pumpkin growers start the year before. They add manure to the place their pumpkin plants will grow. They kill off the weeds.

We are starting in the spring so we have to hurry to get ready. You need to till or spade up your pumpkin area. Add compost and mix it into the soil.

If the spot is covered with grass or weeds, you need to get rid of them. It takes more work but is better for your pumpkin plants if you mulch or till or pull those pesky weeds and grass. Herbicides do kill weeds but can kill lots of other things too including your pumpkin plants.

 

giant pumpkin

This giant pumpkin weighed 878.5 pounds! Giant pumpkins are so heavy they flatten in shape.

When Do We Start?

 Even a little frost will kill a pumpkin plant. Small, sugar pie and Halloween pumpkin kinds can be planted in the garden after spring really arrives. Giant pumpkins can be planted then too but many growers start them in the house before then.

While we wait, we’ll find out more about pumpkins.