Homemade Lava Lamps

Question: Do oil, water and air have different density levels and how do we show it? 



Hypothesis:

We feel that oil,water and air have different density levels. Water is most dense and will stay towards the bottom. Lighter materials such as air will rise to the top.
Picture
Picture

Materials: 

Picture

  • Half liter or liter bottles
  • Water
  • Alka seltzer
  • Food coloring
  • Vegetable oil
  • Funnel
  • Flash light

Safety Procedures

Don't cap the bottles after the alka seltzer is put in, because the capped bottles will be pressurized due to the produced carbon dioxide. The high pressure inside the bottle can potentially cause injuries.

Procedure:

  1. Pour 100 ml of water into each bottle
  2. Add 300 (or 800) ml of oil to each bottle
  3. Wait for bubbles to disappear
  4. Add 2 drops of food coloring to each bottle
  5. Put in half a tablet of alka seltzer
  6. Turn on the flash light and shine it from the bottom
  7. Observe



Special Needs:

A room with a light switch and close to sink

Watch us in action:

Picture
Our Experiment

The Science behind it


When water and oil are mixed in the bottle, water will settle to the bottom, and oil will stay on the top, because water is heavier than oil. In addition, water is hydrophilic, and oil is hydrophobic, therefore they do not dissolve into each other.

When alka seltzer was put in the bottle, air bubbles will come out from the bottom and rise up to the top. The bubbles are colorful from the dye dissolved in the water.

The reason that mixing alka seltzer with water generates air bubbles is because alka seltzer contains sodium bicarbonate (a.k.a. the baking soda), citric acid and aspirin (both are a form of acid). When baking soda mixes with acid in water, it creates carbon dioxide, a gas that does not dissolve in either water or oil, which are the air bubbles that rise from the bottom to the top.

Vocabulary
hydrophilic: having a tendency to mix with, dissolve in, or be wetted by water.Later on you can Add Graphs with results
hydrophobic: lacking affinity for water; repelling, tending not to combine with, or incapable of dissolving in water


Conclusions

The water and oil did not mix, and the oil stayed on top of the water. The alka seltzer at the bottom produced carbon dioxide, which formed air bubbles rising to the top of oil. Therefore it confirms our hypothesis.

About Author 1

Conor McCooey loves Lego's, Minecraft, his iPod, MMA, the Jets, his dog, no homework on the weekends, Somers and working on this science project with his friends.

About Author 2

Dominick D'Ambrosio
I am 10 years old, I like to
draw, I am a gamer, I am a
MMA fighter at Bad Mikey's.
I'm very excited to be part of this science night. 

About Author 

Daniel Zhang 
I am 10 years old, and my teacher is Mrs. Luke. I love music, sports and reading. Science is one of my favorite subjects.