Science Behind Homemade Lava Lamp

This is a Lava Lamp, this shows how alka seltzer reacts with the water to make carbon dioxide bubbles. This also shows how the denser liquid sinks to the bottom of the bottle, but the lava lamp heats up the water until it expands and causes it to be less dense, so it moves up. Instead of using a light to heat up the bottle that is what the alka seltzer is used for. The bubbles attach them selfs to the chunks of colored water and bring them to the top of the glass. The bubbles pop and the chunks of colored water fall back down to the bottom of the container. This is repeated many times, this is also how this type of project got its name and it is still really popular today.

1: You will need a clean plastic water bottle ( one with smooth sides will work better)

2: Water ( does not matter what kind/flavor regular water will work better though)

3: Vegetable Oil (Mineral, or Baby Oil will also work if you don't have Vegetable Oil, but it will work better with Vegetable Oil)

4: Fizzing tablets ( Alka Seltzer will work best)

5: Food Coloring ( does not matter what color you decide to use)

First you are going to fill the bottle about 2 quarters full of vegetable oil. You should have space left over, you are going to fill this empty space up with water. Now your bottle should be full, you don't have to fill it up to the top.

Then you add your food coloring to the mixture. It doesn't matter what color, we decided to use the yellow for our color.

Go and break up the alka seltzer into four small pieces, and add them into the lava lamp 1 at a time. Wait a few seconds before adding another one in the lava lamp. Alka Seltzer is a mixture of baking soda and citric acid.

Now your lava lamp should start springing into acton. The bubbles should start to form and begin going up and down, through out the glass.

The main reason why we did this was not just because it was a fun project but also because we wanted to know the science behind a simple and common project. Lava lamps work because of density and polarity. If you measure an equal volume of oil and water, you'll find that the water is heavier than the same amount of oil. This is because water molecules are packed more tightly. A cup of water actually has more mass than a cup of oil. Because water is more dense than oil, it will sink to the bottom when the two are put in the same container. The denser liquid sinks to the bottom, but the lava lamp light heats it up until it expands and becomes less dense, causing it to rise upward. As it gets farther from the light, it cools down, becoming more dense again until it sinks. Then the cycle starts all over.The alka seltzer reacts with the water to produce carbon dioxide gas bubbles. These stick to the water droplets. The water/gas combo is less dense than the oil, so they rise to the top of the flask. Density is the measurement of how compact a substance is how much of it fits in a certain amount of space. Polarity prevents the oil and water from mixing together.