Just yesterday my biology class did a very interesting experimnent. We all made our own little lava lamp. The lava lamp was invented by Edward Craven Walker in 1963. A lava lamp is defined as a display device with the creation of colored globs of oozing wax suspended in water (mixed with a cocktail of “secret ingredients”) and encased in an illuminated glass tube. Edward Craven Walker got the idea for this creation after walking into a pub. He spent the next 15 years perfecting the invention so that it could be mass-produced. The Astro Lamp, later called the Lava Lamp, was launched in 1963. This all happened just in time for the Hippie/Disco age of the Lava Lamp.
In the lab we filled a water bottle 3/4ths of the way up with vegetable oil and we filled the rest of it with the ol' H2O. After that we put in some color with some food coloring to make it look more psychedelic. Then we added the Alka Seltzer tablets (You could of used salt too, but Erika and I decided to go with the tablets.) After we added a couple of those our lava lamp came to life! It started bubbling and looking just like a cheap lava lamp you by at a yard sale. It was AWESOME.
The person that was across from us at the table, Chelsea, used the salt and it seemed like the salt didn't have as much affect on the lava lamp. That could be because she had to stir hers and it mixed up everything for a bit, but then again it could be because it didn't have the same chemical composition as the Alka Seltzer. All in all it was a successful experiment, and it was definitely enjoyable.
I answered the discussion questions in the video already, but I will go through them again through text.
Why does the oil "float" on water and not vice versa?
For an easy answer - The oil floats because it is less dense then the water. In other words it weighs less. For a more in depth answer - Pure waters density is 1000kg/m³. Oil is usually around the 800kg/m³. Therefore the lighter less dense fluid floats to the top. Just like how a balloon filled with helium floats, the helium is less dense than the air.
Why doesn't the oil and water mix?
The oil and water doesn't mix because because oil is hydrophobic. If you don't know what that means look at the prefix and suffix. Hydro - Water, Phobic - Fear. Pretty much the oil is afraid of the water and doesn't mix. This is based on the oxygen molecules and how they interact with each other.
Why do you thin the food coloring didn't adhere to the oil?
I think that it didn't adhere to the oil because, well...the food coloring is hydrophilic (Water loving) and it mixed with the water instead. (Yessssss, I know this one was short, please forgive me. ;)Discuss the creation of the "lava". What do you think is happening?
I think that the "lava" is created because the Alka Seltzer tablets react and oxidize the water making the food-colored water float through the oil making it look like a lava lamp.