Just so you are not confused, this is not a real lava lamp…you can’t plug it into the wall or anything. But it does, however, imitate the look of a lava lamp! This makes for a great science activity for kids!
Related Post: 25 Awesome Science Fair Ideas For Kids
How To Make A Lava Lamp
Homemade Lava Lamp Supplies:
- a 16 oz. or 1 liter bottle (we used a 2-liter and it used WAY too much oil)
- vegetable oil (or whatever kind you have),
- a funnel
- food coloring
- Alka-Seltzer tablets
*Alka-Seltzer tablets are considered medicine and contain aspirin. Do not let your child handle this medication.*
Step By Step Lava Lamp Instructions:
STEP 1. Fill your plastic bottle half-full with oil. This is why I suggest using a smaller bottle…we used over half a bottle of oil with this experiment alone!
STEP 2. Fill the remaining half of the bottle with water. Have your children watch as the water separates and slowly sinks to the bottom (because the water is heavier).
STEP 3. Add 10 drops of food coloring. Make sure to use only 1 color.
STEP 4. Cut one Alka-Seltzer tablets into fourths. Again, do not let a child handle the Alka-Seltzer tablet as it is medication.
STEP 5. Drop one of the pieces of Alka-Seltzer into the top of the bottle and watch what happens!
To get the “lava-lamp” effect, you’ll need to add another fourth of Alka-Seltzer every 30 seconds or so.
The Science Behind This Lava Lamp Experiment:
Oil and Water
Both the water and the food coloring sink to the bottom of the bottle while the oil floats at the top because water is heavier than oil. The food coloring dissolves in the water but not in the oil.
How does Alka Seltzer work?
When you drop the piece of Alka-Seltzer into the bottle, it reacts with the water and creates carbon dioxide gas bubbles. Because the food coloring has already dissolved into the water, the bubbles are “colored” and float to the top! Once they ‘pop’, the colored bubbles sink back to the bottom of the bottle.
This post was first published May, 2012. Last updated 2018.
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