PLAY & LEARN – elementary school (7-12 years)

based on USGS website

Animal Tracks

Save Animal Tracks as Plaster Casts 


What kind of wild animals live near your house?

There are more than rabbits and squirrels, for sure. You might be surprised to find out how many kinds of critters live nearby. With a little detective work, this project will help you discover where some of them live. Also, you will learn how to make plaster casts of their footprints so you can start a collection of their tracks. It’s simple and fun.


Here’s what you will need

A one- or two-pound bag or box of plaster of Paris. This is a powder that looks like flour. You can buy plaster of Paris at the hardware store. It is not expensive. A mixing bowl – a small plastic container such as Tupperware or a plastic cereal bowl. Actually you can use anything that will hold one or two cups of water without leaking, but plastic is reusable and easier to clean. You will be mixing the plaster with water, so it is also better to have something shallow and wide rather than something tall and narrow.

–      a bottle of waterimage034

–      a 16-ounce plastic soda bottle works great

–      an old spoon

–      a 2-liter soda bottle cut into 2 inch sections

–      a few sheets of newspaper to wrap

the track cast

–      a bag or knapsack to put all of this stuff in

–      oh yeah, old shoes and clothes that you can get

muddy in


Let the detective work begin

Look for tracks on wet ground and soft mud. The best place to look is where animals go to drink water. The bank of a creek, stream, river, pond, or lake is a great place to start. Sandbars are good places, too. The edges of mud puddles shouldn’t be overlooked.


How to make a plaster cast


Once you have found a good clean track that you want to keep, gently clear away any debris around the track. Remove any leaves, small stones or twigs without disturbing the track.

Place one soda bottle ring around the track so that the track is centered, and press it about 1/2 inch into the ground. This makes a sturdy circular wall that will keep the plaster from running out.



Mix up some plaster


Pour about a cup of water into your mixing

Follow the directions that came with the plaster. If you don’t have instructions, here is how we do it in the field: carefully begin sprinkling some of the plaster into the water. When the plaster looks like the top of a volcano and is about 1/2 inch taller than the water, stop. (See drawing. It’s worth a thousand words.) Let it sit for a minute or two so that the plaster absorbs some of the water.


Next, begin slowly (slowly is the magic word) stirring the plaster and water with your spoon until it is creamy like pancake batter. Here is another hint: you don’t want to get air bubbles into the plaster mix. They take away some of the detail of the track. Don’t whip the mix. Just stir it gently until it is evenly mixed and has no lumps.


Gently tap the bottom of your mixing bowl on a rock or a fallen tree trunk to remove any air bubbles. As you tap you will see bubbles come to the top. Aren’t you glad you didn’t whip the plaster? Keep tapping until the bubbles stop coming up.Now you are ready to pour the plaster into the circle you made earlier. Do not pour the plaster directly on the track. It might ruin it. Instead, pour to the side of the track and let it run into the track. Fill the circle to the top.


Now you are ready to pour the plaster into the circle you made earlier. Do not pour the plaster directly on the track. It might ruin it. Instead, pour to the side of the track and let it run into the track. Fill the circle to the top.

This plaster thing you have just made is called a cast. It needs to harden for at least 30 minutes. An hour is better. Even after an hour, the cast will still be soft and will easily break if handled roughly. This is a good time to look for more tracks. Can you find any bird tracks? How about snail tracks?

When the time is up, it is time to remove the cast. Start removing the mud 4 or 5 inches outside of the cast. Next dig away the mud below the cast. Carefully lift up the cast. If there is any resistance, stop. Dig out some more mud. Do not try to pry the cast out with a spoon or a stick. It will crack. Lift it out gently with your hands.


Wrap the cast in newspaper to protect it on the trip home. It is still very fragile. It will be for about two more days. When plaster is drying it feels warm to the touch. The cast will be ready to clean after it feels cool to the touch.

Then you can paint it if you like.


Animal Tracks Reference Guide

See if you can match your animal track casts to one of these common animals:

image048 image050 image052 image054 image056 image058 image060 image062 image064 image066 image068 image070



Mealworm Ranch

An experiment in scientific observation 

You have probably heard about caterpillars turning into butterflies or tadpoles turning into frogs. You may have even heard about frogs turning into princes, but that happens only in fairy tales. A lot of animals start life in one form and change into a completely different shape when they become adults.

Scientists call this process metamorphosis (met-a-MORF-a-sis).

Mealworm Ranch is a project that will let you see first-hand how metamorphosis works.

Here’s what you’ll need to get started:


image075 image077

1. A container about the size of a shoe box

2. Oatmeal. That’s right oatmeal.

3. One or two carrots.

4. A dozen or so mealworms, which can be purchased inexpensively at any pet store.

5. A notebook so you can record your observations as the mealworms go through metamorphosis.

Note: mealworms are clean and harmless, so it’s OK to pick them up gently with your fingers.


Making a habitat for your experiment:

1. Punch a few holes in the top of the container for air.

2. Dump the oatmeal in the container so the caterpillars have something to eat.

3. Place the carrots in the container so the mealies will have some water. Carrots are full of water, so replace them if they dry out.

4. Place the mealworms in the container. Remove any that are dark brown or black.

5. Put the lid on the box. Mealworms are good climbers, so you should keep the lid on unless you are actually watching them.


Now you are ready make some notes in your notebook.

You might want to draw what these guys look like the first day. You might even write some notes about what you see. For example:

  • What color are the mealworms?
  • How long are they?
  • How many legs do they have?
  • Do they all seem to have the same number of segments?
  • What happens when the mealworms are put on top of the oatmeal?
  • How are they moving?
  • Do they get along with each other?
  • Do they make noise?
  • Where do they prefer to live?
  • You can think of more questions and write them down to see if you can find the answers.
  • Keep checking each day to see if anything has changed. Can you tell what they are eating?
  • Are they growing?

Write down any changes you find. Keep watching. Write and draw in your notebook often. You are going to be surprised when you see the results.


Plant a Tree


The best time to plant a tree

Spring and fall are the best times to plant a tree. This allows the tree to grow roots before the freezing of winter or intense heat of summer.

How to plant a balled or burlapped tree


What is a balled or burlapped tree? The tree roots are wrapped in burlap or plastic that looks like a big ball at the bottom of the tree. Burlap helps keep the soil around the roots when the tree is being moved.

Dig the hole. It should be as deep as the soil in the ball. The width of the hole should be at least three times the width of the ball. Loosen the edges of the hole, especially the bottom. This will help the new roots to grow easily.


Pick up the tree by the ball and place it in the hole. Never carry the tree by the trunk, because the weight of the ball will shift causing the roots to break.

Place the tree in the hole and arrange it in the center.

Remove the burlap or plastic from the ball.

Make sure the tree is standing straight, then backfill the rest of the hole with a combination of earth from the hole, peat moss, and composted manure. Do not compress the backfill. The backfill should not go any higher up the trunk than the root ball.

If your tree is three feet or taller, you should stake it so it doesn’t start to lean over as the soil settles. See diagram.

Water the tree very well every day for the next few weeks. Later you can water every week or so, depending on your climate.


Planting bare-rooted trees


Planting bare-rooted trees is a little different from planting balled trees. For one thing, bare-root trees will dry out quickly, so you have to make sure the roots don’t dry out. Another thing is that the roots should be carefully trimmed to remove any damaged roots. Just trim them back to the healthy roots. Save as much of the healthy root system as you can.


Dig a small hole and make a cone of dirt in the bottom of the hole.

Place the tree in the hole and spread the roots of the tree evenly around the cone. Make sure the crown, where the roots met the trunk, is about two inches above the top of the soil. See illustration.

Hold the tree so it is straight, and backfill as above.

Water every day for the next few weeks. Later you can water every week or so, depending on your climate.