The Gelatin Lab

Materials Needed

• Unflavored gelatin (such as Knox) or flavored, light-colored Jell-O, enough to make two quarts
• Small, round bowls shaped like a volcano (margarine tubs and mixing bowls work well)
• Red food coloring (to mix with water to make "magma")
• Syringe for injecting magma (best to use a plastic variety found at pet stores for feeding birds)
• Peg board, 1 x 2 feet with holes 0.25 inches in diameter spaced an inch apart
• Two bricks, 1 foot high
• Tray to keep "magma" off the tabletop
• Rubber gloves to avoid staining your hands

Directions

1. Prepare 2 quarts of gelatin for the volcano molds. Bring 6 cups of water to a boil. Put 2 cups of cool water into a large bowl and add 4 packages (a whole box) of Knox gelatin, stir for half a minute. Then add all the boiling water and stir until the gelatin is dissolved. Let mixture cool for a few minutes then pour into small bowls. Refrigerate gelatin for at least three hours.
   
   Knox unflavored gelatin is clearest and ideal for the experiments, but not tasty, so you may want to try flavored Jell-O. Lemon is most transparent. Make it according to the recipe adding an extra 10% of water because Jell-O is less elastic than Knox gelatin.

   Prepare colored water for "magma." Pour about 6 ounces of water into a glass; add food coloring until the color is blood red.

   Remove the small bowls from the refrigerator. Loosen the gelatin from the bowl by holding it briefly in a larger bowl of hot water.

   Transfer the gelatin mold upsidedown to the center of the peg board and lift off the bowl. The gelatin should resemble a colorless to milky, shimmering volcano. The gelatin will settle somewhat after being removed from the bowl.

   Place the peg board on top of two bricks as shown in the set-up diagram.

   Fill a syringe with red water. Holding the syringe upright, squirt a small amount of water out to remove any air bubbles. Air tends to fracture the gelatin.

   Predict what will happen when the red water is injected into the gelatin volcano. What shape will it take? What direction will it go? Will it erupt through the surface of the gelatin? If so, where?

   Insert the syringe through a hole in the peg board into the center of the gelatin volcano. Inject the red water slowly, at a rate of about 20 cc/minute. Watch the volcano carefully. Compare what you see to your predictions.

   Refill and insert the syringe as many times as possible. Compare the magma migration each time. Are there differences in the direction the magma moves during injections in the central part of the gelatin volcano compared to injections near the edges?

   Looking directly down on the volcano, sketch the positions and shapes of the "magma bodies."

   Use a sharp knife to cut the gelatin volcano in half. Examine the cut surface. Note the traces made by the red magma; these are similar to what we see in highway road cuts. Compare what you see in two dimensions on the cut surface to what you see looking into the gelatin.

The Traditional Volcano

Things you will need

• Soup cans
• Vinegar
• Water
• Baking soda
• Teaspoon
• Food coloring (red)
• Sand
• Soil or leaves
• Clay (to be used to build a mound around the volcano)

Directions

1. Place the can on the ground outside or on a paper plate or tray, if inside.

2. Have children build a mound around the can using soil, sand, leaves, clay, or paper to create their own image of a small mountain.

3. Fill the can 1/2 to 3/4 full with vinegar. Add a few drops of red food coloring, then a spoonful of baking soda.

4. Watch the lava flow down the sides of the volcano as the chemical reaction between the acid and the baking soda occurs.

5. Repeat as long as the vinegar, baking soda, and interest lasts.