Pinterest for Education: Make Your Own Lava Lamp
This is a great science experiment for students in sixth to eighth grade. Let’s find out if food coloring will mix with oil and water.
Research: Have students look up the word immiscible, which means “not forming a homogeneous mixture when added together.” We all know that oil molecules and water molecules do not mix, but what happens when food coloring is added? Will it mix with the oil or water? What happens when Alka-Seltzer is added?
Hypothesis: Have students write their hypothesis. The goal is to have them write one stating if they believe the oil and water will or will not mix.
All you need is:
- a water bottle
- vegetable oil
- food coloring
- an Alka-Seltzer tablet
1. Fill a little over half of the water bottle with oil.
2. Fill the rest of the bottle with water, leaving an inch at the top.
3. Add 10 drops of food coloring to the bottle.
4. Break the Alka-Seltzer tablet into four pieces, and drop the pieces into the bottle one at a time. Wait until the first piece stops bubbling before dropping the next piece in.
Data: Students should write a paragraph explaining their observations.
Conclusion: What did the students learn by doing this? Their responses should state that when the food coloring is put into the water bottle, it mixes with the water. Food coloring is immiscible in the water and, as a result, forms droplets in the oil as it passes through. When the Alka-Seltzer is added, it reacts with the water to make tiny bubbles of carbon dioxide. These bubbles attach themselves to the food coloring droplets and are pulled back up through the oil. When the bubbles pop, the colored droplets sink back to the bottom.
Try this experiment and let us know how your class responds!