OS18 Inside a Pumpkin

Pumpkins look nice setting on a table but the parts to eat are inside that orange rind. Pumpkins have vitamins and minerals inside. It takes a chemistry lab to look for those. But other things are easy to look for so let’s look inside a pumpkin and see what we can find.

 

Note: Part of this Investigation asks you to cut a pumpkin into pieces. Pumpkins are difficult to cut. You may want an adult to cut the pumpkin up.

Note: If you use a clean table and kitchen knife, bowls and spoon, you can use the pumpkin to cook up some delicious pumpkin treats from the recipe section.

 pumpkin

Question: What is a pumpkin made of?

Materials:

1 Ripe Pumpkin

Kitchen counter or newspapers on a table

Knife

Paring knife

Large spoon

Metric ruler

2 Bowls, labeled

Bathroom scale

Oven

Scale

Procedure:

Step 1: Open your Science Journal. Write “Investigation 18” and the date.

Step 2: Pick a ripe pumpkin. Describe and draw your pumpkin.

Step 3: Break off the stem piece. [It should snap off if pushed flat.] Draw and describe the end of the stem and where it joined the pumpkin.

Step 4: Weigh it on the bathroom scale to the nearest tenth of a pound. Record the weight in Table 1.

cut open pumpkin

How is the seed pattern like the ovule pattern seen in Investigation 16? Why are some pumpkin seeds small and flat?

Step 5: Use the knife to split the pumpkin into top and bottom halves. This is difficult to do. Look at the seed patterns and compare it to the pattern of ovules you saw in Investigation 16.

Step 6: Measure the diameter in cm of the pumpkin. Record it in Table 2.

Step 7: Measure the diameter in cm from the inside edges of the flesh. Record it in Table 2.

Step 8: Measure how thick the rind is (You will have to estimate it.). Record it as the Middle thickness in Table 4.

Step 9: Measure how thick the flesh or wall is. Record it as the Middle thickness in Table 4.

Step 10: Mass Bowl 1. Record it in Table 3 in two places.

Step 11: Try to pull a seed out. Try to follow the string attached to the seed to the other end. Describe the string and seed.

Step 12: Pull the seeds and pulp out putting them in Bowl 1. Use the paring knife and spoon to remove as much of the strings as you can.

pumpkin pulp and seeds

It takes a lot of scraping to get all the pulp and seeds out of a pumpkin.

Step 13: Mass the bowl, pulp and seeds. Record it in Table 3.

Step 14: Mass Bowl 2. Record it in Table 3.

Step 15: Separate the seeds from the stringy pulp putting them into Bowl 2.

Step 16: Mass Bowl 1 with pulp and Bowl 2 with seeds. Record these in Table 3.

Step 17: Weigh the empty pumpkin on the bathroom scale to a tenth of a pound. Record the weight in Table 1.

Step 18: Cut each half in half. The stem part will be difficult to cut through.

empty pumpkin

Will the circumference around the middle of this pumpkin be bigger than the circumference around the top and bottom? What’s in the middle of a pumpkin?

Step 19: Measure how thick the rind is at the stem end or top and at the blossom end or bottom of the pumpkin. Record these in Table 4.

Step 20: Measure how thick the flesh is at the top and bottom of the pumpkin. Record these in Table 4.

Step 21: Hold top and bottom pieces together and measure the diameter. Record it in Table 2.

Step 22: Measure the diameter between the inside edges of the flesh. Record this in Table 2.

Step 23: Write down the percentage of water you think is in a pumpkin.

Step 24: Cut out three square pieces of the flesh and rind about 1.5cm on a side. Mark 1, 2 and 3 on the rind end with a marker or pen.

original pumpkin pieces

Measuring several pieces of pumpkin instead of just one should be more accurate. Right?

Step 25: Mass each of the pieces. Record the masses in Table 5.

Step 26: Dry the pieces. You can use an oven set very low [200º or less], a dehydrator or a warm place. The time needed will depend on how you dry the pieces. The heat must be low so the pieces do not cook.

Step 27: When the pieces are very dry, mass them again. You may want to let the pieces dry a while longer just to make sure, then mass them again.

Note: Use the seeds for Investigation 19. Use the pulp for making pumpkin puree for the recipes.

Observations: 

Describe your pumpkin.

OS18 Table 1

Is more of a pumpkin’s weight in the flesh or the pulp and seeds?

Describe the stem end of your pumpkin.

OS18 Table 2

How does the circumference change for the inside and outside of a pumpkin?

Describe the arrangement of the seeds inside your pumpkin.

Describe the seeds.

OS18 Table 3

Is there more pulp or seeds in a pumpkin?

Describe where the string goes from a seed to the pumpkin wall.

Describe how the seeds attach to the pulp.

OS18 Table 4

Are the rind and pulp thicknesses the same all over the pumpkin?

Write down the percentage of water you think is in your pumpkin.

OS18 Table 5

How much water is in a pumpkin? Does it matter how long since the pumpkin was picked?

Analysis:

 

empty pumpkin halves

After the pulp and seeds are out, the two halves of a pumpkin look like two thick orange bowls.

Table 1:

Subtract the weight of the empty pumpkin from the original pumpkin weight. Record it in Table 1.

Multiply the pounds by 2.2kg to find out how many kilograms each of the weights would be. Record it in Table 1.

Table 2:

Find the average outside diameter by adding the two outside diameters and dividing by 2. Write this in Table 2.

Find the average inside diameter by adding the two inside diameters and dividing by 2. Write this in Table 2.

Multiply the two diameters by p or 3.14 to find the circumference for the outside and inside of your pumpkin. Write these in Table 2.

Table 3:

Subtract the masses of the bowls to find the masses of the pulp and seeds together, pulp and seeds.

To do these calculations, be sure all the masses are in kilograms or in grams, not in both in the same calculation. Divide the mass of the empty pumpkin by the mass of the original pumpkin and multiply by 100%. Divide the mass of the pulp by the mass of the original pumpkin and multiply by 100%. Divide the mass of the seeds by the mass of the original pumpkin and multiply by 100%.

Table 5:

Subtract the dry mass from the original mass for each of the pieces. Write this in Table 5.

Find the averages by adding the three values in each column and dividing by three. Write this in Table 5.

Divide the difference by the original mass of the piece and multiply by 100% to find the percent. Write this in Table 5.

 

dried pumpkin pieces

Dried pieces of pumpkin are much smaller than the original pieces. How much water is in a pumpkin?

Conclusions:

Is most of the weight of a pumpkin in the seeds and strings or in the pulp? Why do you think so?

If you wanted to breed a pumpkin for the most weight, is the size of the whole pumpkin or the thickness of the pulp more important? Why do you think this?

If one pumpkin is tall and thin and another is short and fat, how will this affect the width and height diameters?

When you average the width and height diameters, what shape of pumpkin are you ending up with? Why do you think so?

If you have a very heavy pumpkin and another the same size but much lighter, how will the outside and inside circumferences compare for the two pumpkins?

If you add up the separate masses of the seeds and pulp from Table 3, do you think it will be the same as the original mass? Try it. If the two masses are not the same, why is there a difference?

Why do you think the diameter of the rind stays the same but the diameter of the pulp changes in different parts of the pumpkin?

What does the rind do for the pumpkin?

Giant pumpkins are flat when they get very big. Why do you think this happens?

Why do you think each seed has a string attached?

What do you think would happen to a developing seed if its string broke?

Drying the pieces of pumpkin evaporated the water. How important is water to the weight of the pumpkin?

Why did you dry more than one piece of pumpkin? Were the percentages of water the same for all three?

Do you think a pumpkin picked a week before you dried pieces would have as much water in it as one you picked the morning before? Why do you think so?

If you were growing a pumpkin for a competition, how important is it to water your pumpkin plants regularly? Explain why you think this.