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## Weekend Science Fun: Pumpkins and Apples

Don’t you love going to the grocery store this time of year, with all the pretty pumpkins and fresh apples? Wouldn’t it be fun to use some pumpkins and apples for science activities?

Gather a few pumpkins and apples. Get some different sizes, kinds and colors, if possible. Depending on which activities you try below, you will also need a bathroom/kitchen scale; a container, such as a large plastic bin, to hold water (for floating); a cutting implement; and trays for holding fruit parts. Each child will also need paper and pencils/crayons.

Exploration/Botany Vocabulary
Have your children look at the pumpkins and apples. How are they different, how are they the same? Both pumpkins and apples are fruit, and have seeds inside. Both have stems, can you find the stem? What is the stem for? Apples have a skin, does a pumpkin? (Yes, it does). You can ask older children what they think the fleshy meat (the part we eat) is for.

Sorting
Have the children sort the pumpkins from the apples. They can also sort the sizes, from smallest to biggest, or by color. (Sorting is such an important scientific skill, one that tends to get forgotten.)

Weight Estimation
Have the children estimate how much they think each pumpkin/apple weighs. Ask them how they would weigh a big pumpkin. Help them weigh the pumpkins and apples.

Pumpkin/Apple Floating
Will a pumpkin float? Will an apple float? Does it matter how big it is?

Fill up a large container with enough water to float the biggest pumpkin without slopping over. See if the different fruit will float or not. Have the children bob for apples, if appropriate. Have the children draw what happened.

Seed Estimation
Have the children estimate how many seeds they think are inside each pumpkin or apple before you cut the fruit open. Write down the estimations and compare with the results below.

Pumpkin/Apple Exploration
Begin to cut into the pumpkins by cutting around the stem, like you were going to make a jack-o’-lantern. Allow the children who want to explore to get their hands inside. Let them feel the seeds. Cut the apples and allow the children to search for seeds. Have them count the apple seeds. See if slices will float (see above).

Sorting Seeds Video

Here is a video showing one way to sort pumpkin seeds with preschoolers.

Let It Rot!
Rotting or decay is a mysterious and fascinating process for children. In our modern ultra-clean world of antibiotics and hand sanitizers, we forget what an important process it is. If at all possible, find a quiet corner and let the pumpkin or apple rot. Check the progress daily. Admire the molds that develop. Discuss the odors. If rotting isn’t progressing, add a bit of water.

Grow or Eat the Pumpkins Seeds
You might want to save some of the pumpkin seeds to grow. If so, wash them and let them dry. Don’t heat them/cook them if you want to plant the seeds. Check one of the websites below for more information on growing pumpkin seeds.

Edit: Since I'm getting a lot of questions about growing pumpkin seeds, I am going to add a link to my website. "Growing Throw Away Seeds" talks about how to grow seeds that we eat, or that we might throw away, like pumpkin seeds. You might also want to try pumpkin seeds in the homemade root viewer.

Or your can oven-dry some of the seeds for eating.

Celebrate Fall by making some of your favorite recipes. Here’s one of ours:

Pumpkin Pie in a Glass Smoothie

Add to blender:

1 to 1 1/2 cups canned or pureed cooked pumpkin
2 cups milk, soymilk or ricemilk
1/3 cup sweetener such as maple syrup
1 cup tofu
1 tsp cinnamon
dash nutmeg
1/4 tsp cloves

Blend until well mixed. Makes 4 8oz. Servings.

Websites for further information:
Pumpkins and More Website

Pumpkin Circle – Info on growing pumpkins http://www.pumpkincircle.com/ Edit: Follow the link through the Pumpkin circle, click to enter the site and then look through the list for information on growing pumpkins.
Classroom activities at http://www.sadako.com/pumpkin/activities.html also has information on growing pumpkins in the classroom.

Books ( repeated from theme garden post):

Pumpkin Circle: The Story of a Garden by George Levenson, Shmuel Thaler (Photographer)

I love this book because it isn’t afraid to show rot.

Check this list of Fall–inspired books from the MissRumphiusEffect Blog.

Patty's Pumpkin Patch by Teri Sloat

Follow the progress of a pumpkin patch through the seasons while finding items from the alphabet. For example, in the field where the pumpkins are being planted, “a” is for ant and “b” is for beetle.

## A Question About Insect Blood 1

A question came in this week that was out of the ordinary and I thought I’d share it here.

Question:  “I have a crazy question and figured that you are the best person to answer it.  On Wednesday, I am leading a class about the skeletal system, and I am anticipating a question from one of the younger kids.  I don’t know how to answer it.  How do insects make their blood?  In humans, blood is manufactured in the bone marrow.  Is the exoskeleton of an insect also responsible for blood production?”

Answer:  An insect's blood is called hemolymph (or sometimes haemolymph), and it circulates around the interior body cavity, between the exoskeleton and the inner organs. It is a yellow, greenish or pale-colored fluid. The hemolymph is moved about by the insect’s hearts and by the movement of muscles, but the whole system is much more open than that of vertebrates. The hemolymph is not carried in closed channels like the arteries and veins of humans; it flows freely.

The liquid part of the hemolymph, or plasma, is about 90% water. The water comes from the insect’s food and what it drinks. The water enters the body cavity through the cells of the digestive tract. Right before an insect sheds its exoskeleton or molts, it increases the volume of liquid inside its body, and thus pressure inside. The insect does this both by excreting less (its "kidneys" are called malphigian tubules) and also by drinking more. The increased pressure is used to expand the new, soft exoskeleton while the insect is molting. After the insect has finished molting and its exoskeleton has hardened, it excretes the excess water to reduce the pressure to normal again.

Within the plasma are cells called hemocytes, which carry out some of the same functions as our white blood cells, such as capturing foreign particles (phagocytosis) and wound healing. The hemocytes are derived from the mesoderm in the embryo (which one of the embryonic tissues). It is thought that the hemocytes formed in the embryo give rise to all the new hemocytes through cellular divisions. Insects don't have anything analogous to human bone marrow.

For the most part, the hemolymph does not carry oxygen, which is one of the important functions of our blood. Instead tiny tubes called trachea carry oxygen in insects. (You can see the outside openings of the trachea on the sides the green June beetle larva in the previous post.) The trachea reach all the way down to the cellular level. Thus, the hemolymph system in insects is more similar to our lymphatic system.

And, there’s no such thing as a crazy question! ☺

## Bug of the Week: Green June Beetle 4

This week we were grubbing around in the compost heap when we found this. We were quite excited.

It's about the size of my thumb. I can tell it is a beetle larva from the fact it has a hard head capsule (dark brown) and six distinct legs right behind its head. Those small brown circles on its sides are the opening of the airways it uses to breathe. Those are called trachea.

I knew what kind of beetle it was when it flipped onto its back and began crawling along upside down. My son said this was “Freaky!” (I think that is tween-speak for “Really cool!”) You can see the legs better. It also has bristly brown hairs. It quickly crawled off, upside down.

This interesting critter is a green June beetle grub, Cotinus mutabilis. They are a type of scarab beetle. The larvae (grubs) feed on compost and help with decomposition. They are up to two inches long when mature. Next Spring it will pupate in the soil and emerge as an adult.

The adults have beautiful metallic green wings with brownish-gold at the margins. They congregate in large numbers to feed on various types of soft fruit, which gives them their other common name, figeater beetle. Their normal food in Arizona is prickly pear or saguaro cactus fruit. They also visit our desert willow flowers for nectar.

I only have a photo of a preserved specimen. Don't worry, all of our preserved bugs died of natural causes.

The adults are even shinier when they are alive. Isn't it interesting such a "freaky" larva can turn into such a spectacular adult? Talk about the ugly duckling...

By the way, if this grub hadn't scooted away so quickly, it would probably have been bird food. Grackles love them.