The Magic Egg
Science Concept: Density
An egg will float on top of a more dense liquid.
Materials: 2 raw eggs
50 mL of sugar
50 mL of vegetable oil
two 400 mL beakers filled halfway with water
Directions: Fill both of the beakers halfway with water. Add 50 mL of sugar to one beaker and add 50 mL of vegetable oil to the other beaker. Stir both beakers well. Place an egg in the beaker of sugar water and place a second egg in the beaker of water and oil. Take note as to which egg floats and which egg sinks.
Introduction & Commentary: Does anyone know why certain objects float and others sink when they are placed into a liquid? Who knows what happens to an egg if it is put into water? Well, what do you think will happen if we put two eggs in a mixture of water and other materials? Will the eggs float or sink? Letís come up with some reasons why eggs will float in some liquids but not in others.
Explanation: In plain water, an egg will sink to the bottom because its density is greater than the density of water. When sugar is added to water, however, it increases the density of the water so much that now the density of the sugar water is greater than that of the egg, causing the egg to float instead of sink. Oil, although it looks heavier than water, is actually less dense than water, and therefore rises to the surface of the water. The density of the oil and water combined is not enough to exceed the density of an egg. Therefore, because the density of the egg is greater than the oil and water, it sinks.
Safety Precautions: Use caution when dropping the raw eggs into the beakers. If they are dropped too quickly, the eggs may hit the glass bottom and crack open.
Waste Disposal: Dispose of the contents in the beakers in the sink. Throw the eggs into the garbage can.