Let’s test Density with Liquid Layer Art!
- Isopropyl alcohol
- Food coloring (blue, red, yellow, green)
- Clear cup or glass, a narrow cup works best
- Small cups for coloring your liquids
- Popsicle stick or spoon for mixing
Let’s make art!
- In preparation, make salt water.
- Pour each of your four liquids into their own small cup.
- Use food coloring and color the four liquids as follows: water – blue; alcohol – red; salt water – green; glycerin – yellow.
- Next, slowly pour colored liquids into the clear cup in this order: glycerin, salt water, fresh water, alcohol.
- You will now see which liquid is the most dense. Glycerin will always be at the bottom since it is the densest. Next will be salt water. Then will be fresh water and the alcohol will be on top. The alcohol is the least dense.
How does it work?
Density is the term used to compare the mass of the same volume of different substances. The same volume of two different substances can have different masses. A glassful of water has a greater mass than the same amount of oil. Water is denser than oil which is why oil floats on water. Ice floats on water because ice is less dense that water.
One of the reasons super tankers and cruise ships float on ocean water is because they have areas built into the ships that contain only air. The average density of the ship, combining the steel it is made of and the air, is light compared to the average density of the water.
Is there more for you to do?
If your water and salt water mixed together and you do not see a difference between the plain water and salt water, use a little more salt and remix. Then try your experiment again!
Try these additional experiments!
What other liquids can you test the density of? Try liquids like oil, corn syrup, and vinegar, and do your experiment again! What did you observe?