July 2014

Homemade Lava Lamp (7/23/14)

MATERIALS:

  • Empty water bottle
  • Vegetable oil
  • Water
  • Alka-Seltzer
  • Food coloring
  • Glitter (optional)

INSTRUCTIONS:

  1. Fill up 3/4 of the bottle with vegetable oil.
  2. Pour water in the bottle until it is full. Does the water mix with the oil?
  3. Add 10-15 drops of food coloring to the bottle. The food coloring drops will sink to the bottom and mix with the water. Why doesn’t the food coloring mix with the oil? You can also add some glitter if you’d like!
  4. Break an Alka-Seltzer tablet in half, and drop it into the bottle. Let the bubbly fun begin!
  5. You can store your lava lamp with the cap on. Just add more Alka-Seltzer to make more lava!

HOW DOES IT WORK?
Vegetable oil is less dense than water, meaning that it is lighter than water. That’s why oil floats on top of water! When you add food coloring to the bottle, it won’t mix with the oil because it is water-based. The food coloring molecules are attracted to the water molecules. That’s why the food coloring sinks to the bottom of the bottle! When you add Alka-Seltzer to the bottle, it sinks to the bottom and begins to dissolve in the water, releasing carbon dioxide gas. The lightweight gas bubbles float to the top and bring some colored water along for the ride. When the gas bubbles reach the top, the bubbles will pop, the gas will escape, and the water will fall back to the bottom. Pretty cool, huh?

NOW TRY THIS!

  • Try changing the size of the bottle. Will a bigger bottle produce more blobs of lava?
  • Try adding salt to the bottle instead of Alka-Seltzer. Does anything happen?
  • Turn out all the lights and shine a flashlight underneath your lava lamp before you add Alka-Seltzer. Now watch in amazement!

Silly Putty (7/9/14)

MATERIALS:

  • Elmer’s glue (8 oz. bottle)
  • Borax
  • Water
  • Food coloring
  • Mixing bowl
  • Spoon
  • Plastic cup
  • Zipper-lock bag

INSTRUCTIONS:

  1. Empty the entire bottle of glue into a mixing bowl. Fill up the empty glue bottle with warm water, make sure the lid is on tight, and shake it up! Empty the contents of the bottle into the bowl, and mix well.
  2. Add a few drops of your favorite color of food coloring into the glue-water mixture. You can even practice mixing colors! Stir well.
  3. Measure ½ cup of warm water into the plastic cup, and stir in 1 teaspoon of borax. The borax will begin to dissolve in the water. This borax solution is the secret ingredient that turns glue into silly putty!
  4. Stir a small amount of borax solution in the glue-water mixture. Don’t be afraid to use your hands! You will notice the glue begin to stick together in a big clump. If your silly putty is a little gloopy, keep kneading in borax solution until the silly putty is soft, but firm.
  5. When you are finished playing with your silly putty, store it in a zipper-lock bag.

HOW DOES IT WORK? 
What do plastic bottles, rubber bands, cotton t-shirts, spider webs, your fingernails, and silly putty have in common? They are all made from a material called a polymer! Some polymers are natural and others are synthetic. Polymers are made out of long strands of repeating molecules. Sometimes these long chains of molecules will connect together at several places, creating a stronger and more elastic polymer. This is called cross-linking. Mixing glue with borax and water produces a strong, yet flexible, polymer. The borax solution is the stuff that is responsible for linking the glue’s molecules together to form long strands of stretchy polymers!