A few weeks back, we uploaded a video of our lava lamp experiment! We used alka seltzer to observe how the released gases cause the colored water to float to the surface and drop back again due to the gas release. Here’s our video:

We hope you enjoy 😀

Methodology:

1. Prepare a few Alka Seltzer tablets, a plastic water bottle, water, food coloring (optional, but highly recommended), vegetable oil (any kind is best, we used plain vegetable oil)
2. Fill the plastic water bottle to about a quarter with water. (2L or 800ml doesn’t matter, just any water bottle, but regardless of size, fill a quarter of it)
3. GENTLY pour the vegetable oil in the bottle until the bottle is almost full, but leave approximately 2~3cm space off from the top. We recommend using a funnel(we poured the oil without a funnel and it got really messy, and please gently pour because the more aggressively poured the oil is, the more time it will take to settle down the oil and water)
4. Add about 5 drops of food coloring, which should sink through the oil and diffuse into the water(the more darker the color, the more vivid your lava lamp will be! (it’ll be more easier to see))
5. Break a alka seltzer tablet in half and drop both parts into the bottle respectively. You should watch the lava lamp initiate and really show off it’s color!

At first, we only used a slight mix of a drop of blue and green, which the lava lamp did not show very clearly. So, on our second trial, we decided to mix more food coloring of the same colors to produce a darker color, and the lava lamp was much more vivid and beautiful!

Science behind it:

• Because the density of oil<water, and the density of water = food coloring, therefore, density of food coloring > oil, and food coloring mixes with the water
• Alka seltzer(commonly known as Aspirin) is medically used to help with digestion, but today, we used Aspirin to demonstrate this phenomenon of a lava lamp. During the dissolution process of alka seltzer, it releases carbon dioxide (gas), which is lighter than water, which floats to the top in bubbles of the food coloring water.
• When the air is released from the blobs of colored water, the water gets heavier again as it loses gas, and sinks.

We now wonder whether the same phenomenon would show if the bottle’s lid was screwed on during the gaseous process.

---

Recently, our club posted a video on our Youtube Channel for our recent elephant toothpaste experiment!

Science behind elephant toothpaste:

• Hydrogen peroxide(one of the crucial ingredients) is composed of hydrogen and oxygen atoms (H₂O₂), and it is produced in different concentrations, usually 3% (the concentration we used, along with 30%). Because it is quite vulnerable to light, hydrogen peroxide is often stored in brown battles.
• As decomposition of hydrogen peroxide happens, it decomposes into oxygen(O₂) and water (H₂O), which usually takes quite some time, but this decomposition can be sped up with the addition of a catalyst (= yeast!)
• Yeast contains a catalase that serves as a catalyst to speed up reaction, which in this case, is the hydrogen peroxide.
• Therefore, when we added the yeast solution (catalyst) to the hydrogen peroxide, the decomposition reaction happened very rapidly, resulting into oxygen gas (=bubbles). Because we added dish soap to the hydrogen peroxide, the surface tension increased with the bubbles from the oxygen gas getting trapped, and hence, resulting in a lot of foam. (= “toothpaste so big, one that could be used by an elephant!”)

1. Prepare a measuring cup, a large plastic bottle, hydrogen peroxide(we recommend 3% to be safe), dish soap, food coloring, yeast, and warm water.
2. Pour 1/2 cup of hydrogen peroxide and carefully pour it into the bottle (don’t spill – it can be very dangerous to the skin, so also wear GLOVES!)
3. Add a pump of dish soap into the bottle and gently turn the bottle in small circles to swish and mix the hydrogen peroxide and dish soap together.
4. Gently drop some food coloring along the rim of the water bottle rim to recreate a realistic toothpaste-like model, but do not swish the bottle around this time.
5. In a separate bowl, mix a tablespoon of dry yeast with three tablespoons of warm water(the water temperature should be comfortable enough to touch but not too “cold”), and stir until yeast is fully dissolved.
6. Step back and pour the yeast mixture into the bottle!

– Joanna Kim, April 22nd, 2021, 11:06PM KST