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Time to reveal the identity of the mystery seeds from last week.

I really thought the bright orange pulp would give these away. They are pumpkin seeds!

The common name pumpkin is given to several species of related plants. Most often pumpkins are Cucurbita pepo and Cucurbita mixta. Certain varieties of  Cucurbita maxima and Cucurbita moschata may also be called pumpkins. The terms pumpkin and squash can be quite confusing because they are basically varieties of the same thing.

Pumpkins are thought to originate from in the New World. The scientists found some preserved ancient seeds in Mexico, which they identified as pumpkins. (Just think, the ability to identify mystery seeds is important when you are trying to trace the ancestry of plants! And you thought we were just having fun).

Pumpkins are relatively easy to grow if you have plenty of space in your garden.

You can try to save seeds and grow your own pumpkin, but the results might not look anything like what you started with because the plants are often cross pollinated with other varieties. Maybe you'll come up with the next great type of pumpkin.

The seeds will sprout even when they are fresh from the fruit, they don't need to overwinter or go through a cold period.

The plant is a long, trailing vine with large, lobed leaves.

Pumpkins have large, orange five-lobed flower.  The flowers are separate, either male or female.

if you'd like to try a few simple pumpkin science activities, check Pumpkin and apple science.

Pumpkins are such popular plants you can find a wealth of information about them in books and on the Internet.

Here are some of our favorites:
All About Pumpkins website has history, etc.

The seeds are edible as well as the fruit. Check this recipe for roasting pumpkin seeds.

Pick Your Own has detailed information on how to make a pie from fresh pumpkin. It works!

Pumpkin Circle is a wonderful picture book, and the website has classroom activities.

For even more information:

Continuing with the floating/boats theme we’ve had in previous posts, you just have to see this video:

What do you think? Are you ready to grow a giant pumpkin and give it a try?

Have a fun Friday!

Edit: Check this post for Why Pumpkins Float

One question that has come up (pun intended) from previous posts in this blog is why do pumpkins and apples float? To answer this question, we first need to look at why things float in general.

Do you still have your bin of water? Let’s try floating a few more things.

People have been wondering why things float since olden times. According to legends the ancient Greek, Archimedes, conducted experiments to test why things float or sink. Supposedly he figured it all out while sitting in the bathtub. Our modern interpretation is called Archimedes’ Principle.  It states that a body floating in a fluid is supported (or buoyed up) by a force equal to the weight of the fluid it displaces.

Let’s choose water as our fluid. Do you know how much a cubic centimeter of water weighs? How about a gallon?

A cubic centimeter of water weighs 1 gram by definition. A gallon of water (at a given temperature of 4 degrees C) weighs 8.34 pounds. So, in order to float, an item that weighs 1 gram must displace more than a cubic centimeter of water. An item that weighs 8.34 pounds must displace more than a gallon of water to float.

To test this, obtain a piece of modeling clay. Shape it into roughly a cubic centimeter. See if it will float. It will probably look something like this:

sunk

(Clay at the bottom).

Now, flatten out the same piece of clay and make a boat shape. A flat bottom with a lip around the edge works well. Place it onto the surface of the water. It should displace a lot more water this time and float. Although the weight of the clay didn’t change, the amount of water displaced did change.

float

Have you tried floating a can of diet soda versus a can of regular soda? Both are the same size and shape, will they both act the same when placed in water?

Here’s a silent video demonstration.

Why don’t the two identical objects act the same way? According to the box at the bottom of this How Stuff Works page, diet soda has less sweeteners added, so it actually weighs slightly less for the same volume than regular soda. Because they are both mostly water, that slight change is enough to allow diet soda to float. Cool!

Apples and pumpkins are not solid. The pumpkin has a large hollow inside. Both weigh less than the amount of water they displace, and thus they float.

Try floating pumpkin seeds. What about apple seeds? Do they float?

We found that pumpkin seeds floated, but apple seeds did not. The pumpkin seeds are flat and displace an amount of water roughly equal to their size. On the other hand, apple seeds are compact and round. They displace little water. They don’t have to be very heavy to sink.

A few years ago, our family participated in a contest to build a working boat out of cardboard. We started by investigating various boat designs and materials by floating models in a tub. We learned a lot about sinking and floating. You might want to make some paper boats and try them yourself.

Enjoy!

Instructions to make a Classic paper boat

Another cool design for a paper boat that works well.

Edit: check out this video of a huge pumpkin made into a boat.