We just participated in the Champlain Mini Maker Faire at Shelburne Farms in Vermont. Are you familiar with the Maker Movement? The Maker Movement celebrates a “do-it-yourself” (DIY) mindset – from arts and crafts to science and engineering. There seems to be a focus on technology which is a great way to introduce kids to STEM or STEAM. (STEAM stands for science, technology, engineering, arts, math.)
There were great robotics demonstrations but our decidedly low-tech DIY lava lamps were incredibly popular. Even the robotics club high-schoolers and adults loved them!
Lava Lamps – Great Science Project
This project is a great opportunity for kids to learn about density, color mixing and the properties of carbon dioxide. Ask questions like:
- Which liquid is on top? Why?
- Why does it bubble?
- How does the color bubble up through the oil?
- Why do the color droplets not burst until they hit the water?
Everyone seemed fascinated about how they “worked” so we decided to write up a tutorial. A lot of teachers were interested in making the lava lamps in class and we talked about how you could break up the steps to accommodate multiple days of learning. More than 100 kids made lava lamps at our event, so we bought our supplies in bulk but here are directions for making one lava lamp. Just multiply the ingredients for however many makers you have.
- Empty bottle with cap (12 oz water bottles work well.)
- Oil (vegetable or baby oil)
- Food coloring
- Alka Seltzer tablets broken into 3 or 4 pieces
- Plastic funnel
- Plastic or metal tray (or something to capture spills if they happen!)
- Flashlight or other light source
- Cleaning supplies (oil is slippery!)
Lava Lamp Directions
- Using a funnel, fill the bottles 1/4 full with water.
- Again, using a funnel, fill the remaining 3/4 of the bottle with oil.
- Once the water and oil are separated, add 5-6 drops of food coloring. You can adjust this as you like. The more the better, I think.
- Watch the drops of oil float down through the oil. They remain intact as they float down and it’s pretty fascinating to watch. They’ll lay on the bottom layer of the oil until they break through to the water and the droplets of color burst and color the water.
- Next, add a piece of the Alka Seltzer tablet. The carbon dioxide brings up the color into the oil. When the bubbling stops, just add another piece of the tablet.
- Shine a flashlight through the side or bottom of the bottle.
Observations and Tips
- We used vegetable oil. The vegetable oil worked well but it’s yellow in color so baby oil might be nicer since it is clear.
- Let the oil and water completely separate, if you can. This might be a good stopping place to let the bottle sit overnight. You don’t have to wait for it to completely separate but it will be more visually powerful when you add the food coloring.
- We had adults pour the water and oil. You can decide if you’d like to make this a pouring activity for kids.
- Bottles size doesn’t matter unless you are trying to economize on oil (it can get expensive!) Most of ours were 12 oz which means 8-9 oz of oil per bottle. When we ran out of 12 oz bottles, we moved to 8 oz bottles. They worked just as well as the 12 oz bottles.
- Make sure the caps fit!
- We used baking trays with a shallow lip to catch any spills. The shallow trays let little ones see their lamps.
- Young children might need help putting the food coloring drops into the bottle. Nearly every child was able to drop the Alka Seltzer pieces in.
- Color mixing: we found that yellow and red worked pretty well but red & blue did not. It ended up looking pretty muddy.
- We used our lava lamp over and over again. The oil started to look a little foggy. Not sure if it was reuse or air temperature or humidity. Don’t know if baby oil would have had a different effect.
- To cap or not to cap? We left the cap off during the bubbling process. What would happen if you capped it right away?
- Don’t forget clean up supplies – paper towels, wipes, etc.
Light up your Lava Lamp
The kids loved the lava lamps in regular daylight but were amazed when we shone a light through the side. One child told me later that she used it as a nightlight.
Our neighbors from the CVU Robohawks in Hinesburg, VT made us a light up base for our bottles. They used a 3D printer to make it (took several hours) then, cut holes and put LED lights and a battery underneath. Maker Power!!!
Your lava lamp will last forever. Just add some alka seltzer when you’re ready to watch it in action.