Grade Level: 6th - 8th; Type: Chemistry
In this experiment, we will see if removing fat from a liquid will make it weigh less.
- Can you think of any foods that are rich in fat?
- How much does fat weigh?
Fat is largely insoluble in water, which is why it tends to float and “cake” on top of it. So how would you remove grease and fat from dishes, bowls, pots, and pans? With dishwashing liquid! Dishwashing liquid is a basic solution and acts as a “connector” between molecules of fat and water that normally repel each other. In this experiment, you'll try to measure how much extra weight fat can add to water.
- Some fatty liquid, such as the water your mom used to steam the chicken for dinner last night
- A spoon
- A kitchen scale
- Pen and paper for notes
- If you already have a fatty solution available, then we will go to the shortcut. But if not, you simply have to steam or boil some water, add some chicken skin or pork fat inside and let it simmer for 10-20 minutes.
- Take out the skin/fat and then let the remaining liquid cool at room temperature or in the fridge.
- After cooling, you should be left with a cakey/chalky white “goo” on the surface.
- On a kitchen scale, weigh the fatty liquid. Remember to subtract the weight of the pot/container from your total measurement.
- Using a spoon, scoop all the white “goo” off of the surface and throw it out.
- Now weigh the liquid again. Does it weigh more, less, or the same as before?
- Record your results.
Terms/Concepts: Lipids; Fat; Fatty Acid; Chemical structure; Essential Oils; Water; Density