Suggested Grades

4+

Objective

Students will see the effects of density when a variety of liquids are poured on top of each other and when a variety of objects are dropped into each one.

Materials

• at least 7 small clear plastic cups
• light corn syrup
• lamp oil
• milk
• water
• a piece of cork
• a piece of a candle
• a piece of metal
  *Each object should also be the same size as each other.

Method

Do this activity as a demonstration or in class groups.

Part 1

• Pour liquids in each glass in the order shown below. Pour out a glass of each liquid combination, so you will have 3 filled glasses in total.
  • 1) corn syrup, milk, oil
  • 2) milk, oil, corn syrup
  • 3) oil, corn syrup, milk
• What happened? Draw your observations. Why did this happen? Organize the liquids from most to least dense.(You should be able to some layers clearly because each liquid has a different density. If the layers combine then the top layer has the heavier density than the one that it was poured on top of.)
• Try the experiment with other liquids.

Part 2

• Pour out a little of each liquid in separate glasses. Include a glass with a little water in it. So, you will have 4 glasses of liquids in total.
• Try dropping a piece of cork, into the middle of each liquid. In which liquids did it sink? In which liquids did it float? Record.
• Fish out the cork, or use a new piece that is equal in size and weight, and repeat the process with the pieces of candle and metal.
• Which objects floated the most? Which objects sank the most? Organize the objects for most to least dense.
• Try the experiment with other liquids.