Everyday is a new chance to explore science, and Halloween is a great reason to do something fun while learning at the same time! Some of my favorite activities are things you can do right in your very own kitchen! Here are just a couple of my favorites that are great for families and use ingredients that are pretty easy to find (watch me demonstrate some of these on TV this morning here: http://abclocal.go.com/wls/story?section=resources&id=6480137 - it was so much fun!)
Homemade Slime
Materials:
Elmer's Glue
Borax (sodium borate - this can be found in most household cleaning aisles)
Food coloring (optional)
Plastic cups (to make the mixtures)
Procedure:
1. Make a solution of Borax by adding 2 teaspoons Borax to one cup of water and mix to dissolve.
2. In a separate container, mix equal parts Elmer's Glue and water until completely mixed.
3. Add food coloring dropwise until the glue is the color you desire. Mix equal parts of the glue and Borax solutions and stir until mixed.
4. The slime will quickly become thick and goopy, and is ready to play with! Be sure to wash your hands when you're done. 5. Store in a zip-seal bag to prevent the slime from drying out.
How Does it Work?
The glue contains a type of molecule called a polymer, which is a long chain of repeating units, that's really flexible and can bend in many different ways. These polymers undergo a chemical reaction when mixed with sodium borate - through a process called crosslinking, which alters the chemical structure of the polymer. This makes the the long, flexible chains become more rigid and solid-like, making slime!
Think About It . . .
What do you think would happen if you used more Borax in your slime Would your slime look or feel any different and why? You can set up an experiment to find out if your hypothesis is correct.
Oozing Pumpkin
Materials:
1 pumpkin, real or plastic, with eyes/nose/mouth cut out
Dishwashing liquid
Hydrogen peroxide
Sodium iodide (this can be tricky to find, but you can buy it from the Internet)
Cookie sheet or tray
Glass bowl that's just slightly smaller than the pumpkin
Food coloring (optional)
Procedure:
1. Place the glass bowl inside the pumpkin.
2. Mix together a solution of sodium iodide by adding 2-3 teaspoons to 1 cup of water.
3. Fill the glass bowl about 3/4 full with hydrogen peroxide and add food coloring dropwise.
4. Add a squirt or two of dishwashing liquid, and stir to mix. You want to add enough to make the solution pretty soapy, but stir gently to keep the bubbles down.
5. Add enough of the sodium iodide solution to nearly fill the bowl, then watch as foaming bubbles ooze up and out of the pumpkin's eyes and mouth!
How Does it Work?
The oozing pumpkin involves a catalyst, which is something that speeds up a chemical reaction. The reaction that?s being catalyzed is the break down, or decomposition, of hydrogen peroxide into water and oxygen gas. Hydrogen peroxide can decompose by itself, but it happens very slowly. In this activity, the sodium iodide acts as a catalyst and makes the reaction occur quickly. The oxygen that is formed gets trapped into the soap bubbles, causing the the foamy ooze that you see.
Think About It . . .
What would happen if there was no soap in the bowl? Also, you might notice a slightly brown tint to the bubbles - what might that be from (think about your medicine cabinet)?
There are lots of great websites that have these and even more ideas for Halloween science. Check them out and try one at home for yourself!
About.com - http://chemistry.about.com/od/halloweenchemistry/a/halloweensci.htm
Steve Spangler - http://www.stevespanglerscience.com/experiment/00000152
FunSchool - http://funschool.kaboose.com/fun-blaster/halloween/
KidsScience (lots of great links within) - http://www.kidsnet.org/sfkc/sfkc20031024-1.html
Editor's Note: For more blogs from Dr. Rabiah, visit Science Chicago's website at: http://www.sciencechicagoblog.com
