Learn about different liquid densities and how they interact. In this experiment, young scientists can make a fun lava lamp manipulating different types of densities that clash with water.
What You’ll Need:
- Vegetable Oil
- Food Coloring
- Antacid tablets or Alka-Seltzer
- Mason jar
You will want to create a balance between the water and oil, while also leaving some room at the top of the jar for when the bubbles start forming. We recommend only one or two inches of water – with a few drops of food coloring – then fill a few inches of oil. When this is done, drop a single tablet of Alka-Seltzer into the jar and watch the bubbles grow!
What is Happening
Fats do not have polar parts, which means if oil needed to dissolve in water, it would be forced to break apart the hydrogen bonds that form water. Since water’s hydrogen can’t break down, the oil is forced to remain separate. When you add Alka-Seltzer to the mix, it forms carbon dioxide, sodium citrate and water. Water has a higher density than carbon dioxide, which means that bubbles form and float to the top of the mason jar, taking with it bits of water. As the bubbles burst at the top, any food coloring will sink to the bottom because of its higher density. This process repeats in order to make the lava lamp effect.
For future experiments, try using different oils, different ratios and even different food colorings to see what happens!
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