Ingredients
- 2 cups cold water
- 10 drops food coloring, divided between the molds
- 2 small plastic cups, about 3 fluid ounces each, for the center openings
- 2 small paper cups, about 5 fluid ounces each, for outer molds
- 1/2 cup baking soda, divided into 2 portions of 1/4 cup
- 1 cup white vinegar, divided into 2 portions of 1/2 cup
- 2 teaspoons extra food coloring for the vinegar, optional
- 1 shallow baking tray, at least 10 inches long
- 1 small spoon, 6 to 8 inches long
- 1 measuring cup, 1-cup size
- 1 small funnel, optional but helpful
- 1 old towel, at least 12 inches by 18 inches
- 1 pair waterproof reusable gloves, optional for handling the ice
- 1 sheet plastic table covering, about 2 feet by 3 feet (a reusable tablecloth or cut-open grocery bag works)
Instructions
- Cover the table first with the plastic sheet.
- Place the baking tray on top.
- Set the 2 paper cups inside the baking tray, leaving about 2 inches between them.
- Place 1 small plastic cup in the center of each paper cup, pressing it down gently.
- Pour 2 cups of cold water into the measuring cup.
- Add 10 drops of food coloring and stir slowly with the spoon until the color looks even.
- Pour the colored water into the first paper cup, stopping about 1/2 inch below the rim; repeat with the second cup.
- Keep the center cups balanced by using a small clean object across the top, without blocking the opening.
- Move the tray carefully into the freezer and freeze for 6 to 8 hours or overnight.
- Take the frozen tray out and place it on the towel, letting it sit for 2 minutes.
- Peel the paper cup away from the first ice shape, using warm water if it resists.
- Add a tablespoon of warm water to the inside of each plastic cup and wait 20 to 30 seconds before gently twisting to lift out.
- Spoon 1/4 cup of baking soda into the opening of each ice volcano.
- Pour 1 cup of white vinegar into the measuring cup and stir in the optional food coloring.
- Divide the vinegar mixture into two portions of 1/2 cup each.
- Pour one 1/2-cup portion of colored vinegar into the first volcano, then pour the second portion into the other.
- Watch the foam rise and note how the ice walls become glossy.
Notes
The ice volcanoes are meant to be used right away, as they melt within a few hours. This experiment is perfect for a hands-on outdoor activity, allowing for observation and fun.
- Cook Time: 30 minutes
