How to Make a Homemade Lava Lamp

If you are looking for something fun and educational to do with your kids this summer, then consider giving these homemade lava lamps a try. You might even already have everything you need on hand to make them. Teach your kids some science while having fun at the same time.

Supplies Needed:

  • 16 oz. water bottle
  • Food coloring
  • Vegetable oil
  • Alka Seltzer tablets
  • Funnel

Note: Baby oil can be used in place of the vegetable or cooking oil, and you can use any tall slender bottle in the place of the 16 oz. water bottle.

For this science experiment you will need some Alka Seltzer tablets. You don’t need to buy the expensive name brand ones, just buy the inexpensive generic ones.


Give each child a water bottle and have them pour out half of the water in their bottle.

Place a funnel in the bottle and fill it back up with vegetable oil, leaving about an inch of space at the top of the bottle so that the liquid doesn’t later bubble out.

Next add a couple of drops of food coloring of your child’s choice into each bottle.

Have your child gently shake up the bottle and then set it back on the counter. Have the child watch the water and oil separate. This is the first science lesson for this activity. You can explain to your child that water is denser than oil, which causes it to sink to the bottom of the bottle with the oil remaining on top.

Now for the fun part. Take an Alka Seltzer tablet and cut it into several pieces. You only need about a quarter of a tablet per bottle.

Let your child place a piece of a tablet into one of the bottles of oil and water. Leave the cap off of the bottle as the tablets react with the liquid. The bottle should now start to resemble a “lava lamp” with bubbles floating to the top of the bottle.

Make sure not to place too much Alka Seltzer in the bottle. If you put in too much, the water will get really cloudy and it will lessen the desired effect.


Explain to your child that the gas created by the Alka Seltzer is less dense than both the water and the oil, causing it to rise to the top of the bottle. The reaction caused by the Alka Seltzer tablets is similar to the effect you see when you create your own volcano out of baking soda and vinegar (your next science experiment!?)

When your child is done looking at the lava lamp you can place the cap back on the bottle and put it away for another day. When you get it back out just add another piece of Alka Seltzer tablet and the lava lamp will start up again.

If you want your lava lamp to light up, then look for an LED push light. You can often find these with the flashlights. Just push the light to turn it on and set the bottle on top.

Science experiments don’t have to be boring. With a little creativity and imagination you and your child can have fun this summer learning new things together and having fun spending time together too.

Make a homemade lava lamp with alka seltzer tablets! Fun summer science experiment to do with your kids.


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