Atmosphere: Play Doh model

Begin with 5 (or 4, if you take your photographs without going back and looking at your own directions... sheesh) equal sized balls of Play Doh.  Color is unimportant in this model. 

Place one ball on a piece of wax paper, this is the troposphere. 

Place a heavy book on top of the Play Doh.

Place another ball of Play Doh on top of the book, this is the stratosphere.

Place another heavy book on top of the Play Doh. 

Continue alternating balls of Play Doh and heavy books until you've accounted for the 5 layers of the atmosphere. 

Then unstack the books.  You'll find that as you move closer to the Earth (the bottom of the stack), the layers become thinner.

Scientific Method: How Much Water Can a Diaper Hold?

A different, and very intriguing question to try to answer using the scientific method. 

For a basic investigation, you only need a diaper, water* and graduated cylinder (or measuring cup).  Just for fun, you could add a drop of yellow food coloring to your water supply... it might completely gross you out, but middle school boys will be completely sold on it!

Open the diaper and pour 100 ml of water onto it. 

Hold the diaper by the ends and gently rock it back and forth until the water is absorbed.

Continue to add water, in 100 ml increments until the water is no longer absorbed. 

To take the experiment one step further, you can compare the absorbency of different brands of diapers.  Make sure you use the same size diaper for each brand.  After gathering your results, you could even determine the diaper cost per mL of water held!  Do the more expensive diapers hold more water?  Remember, for the most accurate results, you should test several diapers of each brand. 


*I've always seen this basic experiment done with plain water.  But, if you'd like to simulate urine, mix 9 grams of salt into a liter of water and use that solution.  I've read that the diaper will perform differently with this solution than with straight water.  That sounds like an experiment worth trying! 

Atoms: Is it full?

Fill a large, clear container with rocks/pebbles/marbles.  Ask your students, "Is it full?"  They will answer, "Yes," as no more pebbles can fit in.

Now pour sand in over the pebbles until the container can hold no more sand.  Ask your students, "Is it full?"

Finally pour water in over the sand and pebbles until the container can hold no more water.  Ask your students, "Is it full?"

At this point, you'll get some students convinced that it is full, but others will now be skeptical, based on what you've showed them so far. 

Ask those students, "What else would fit in this glass?"  You're working toward the idea of atoms being tiny particles, so small (some of them) that they could squeeze in between the molecules of water.  Once students have an idea of how small atoms are (sort of, it's awfully hard to truly understand how minuscule they are), you can proceed with your study of atoms. 

Body Systems: Digestive System: Peristalsis

Although gravity aids in the swallowing of food, it doesn't work alone.  Our body actively pushes each food bolus through the digestive system, a process called peristalsis. 

Here's another hands-on model to help your students get a feel for peristalsis. 

The esophagus is made from a leg from a pair of tights or pantyhose.*

Cut the toe off in order to create a tube.

The food bolus is represented by a large plastic egg. 

Place the egg in one end of the tube.  Hold the 'esophagus' vertically so students can see that the food will not just fall through the esophagus - it's going to need a little help.. 

You can return the set-up to the table and have students determine the best way to move the food through the tube. 

They will quickly realize that the egg moves best when the tights/pantyhose above it are squeezed.

This is comparable to the muscles in the esophagus constricting and pushing the food throughout the digestive system.

Of course, we usually consume more than one bolus of food, so you can provide your students with a whole basket of eggs they need to get through the digestive system.  Create several set-ups and have teams of students race!


*Remember the plastic eggs that pantyhose used to come in, back in the day?  Those were the eggs I saw used in this activity originally.  I don't believe you can find those any more (at least without purging your grandmother's house), so I used a large-sized plastic Easter egg.  It works well, though its smaller than the original prop, and as such, you might want to use a child-sized pair of tights to make your esophagus. 

Plate Tectonics: The Break Up of Pangea Flipbook

Have your students watch Pangea break up, while making a flip book.

Professor Braile (Purdue University) has done the hard work - you simply need to copy the maps onto cardstock (for the best results) for your students.  They color and assemble the maps in the proper order. 

Salt Water Painting

Make a batch of super saturated salt water*.

Fill a shallow pan with the salt water.  Cut pieces of paper smaller than the pan, any shape you like.

Drip food coloring onto the water and swirl with a toothpick.


I'm not sure why the red dye looks so metallic in the photos...


Quickly place a sheet of paper on top of the coloring.  When the paper is wet, pick it up and lay flat to dry.

The salt water is much denser than the food coloring, so the coloring floats on the surface, at least long enough to complete this project.  Given time, the food coloring will disperse in the salt water.

*Fill a jar part way with hot water.  Add some salt and stir.  Keep adding salt and stirring until no more salt dissolves (you see the salt sinking to the bottom).  Let it sit for a few hours.  Then pour off the clear water - the super-saturated salt water solution.

Refraction: Where’s the Test Tube?

I have been waiting nearly two years to share this with you, because I was hoping to find the appropriate lab-ware to borrow so I could photograph this VERY cool demonstration.  But, it hasn't happened yet and doesn't look like it will in the near future, so I've decided to share it with you, without any photographs.  I hope you'll try it.  If you do, maybe you'll take some pictures and be interested in sharing them!

Pyrex has the same index of refraction as corn oil. As such, this demonstration will only work with corn oil, not with any other kind of oil. 

Put some CORN oil in a beaker.

Place an empty test tube in the corn oil - it will appear bent due to refraction. Then, begin to fill the test tube with corn oil - the test tube will disappear! This could also be done with a small beaker.

If you have a mature audience, try this trick… place a broken test tube (be VERY careful, Pyrex is SHARP) into the beaker of oil (which already contains the hidden test tube), telling the students that it’s a restorative potion. Then pull out the whole, hidden test tube!