Why do raw eggs float in saltwater

Why does the egg sink in regular tap water, but float in saltwater? The answer lies in the density of water! Density is a measure of the mass per unit volume of a substance.

The egg will sink in regular tap water because the density of the egg is greater than the density of water. When you add salt to the water, you are increasing the density of the water by adding more mass or stuff in the given volume. By adding enough salt, you increase the density of the water so that it is higher than the density of the egg and the egg will float! Try this experiment again, but instead of using an egg use a potato slice or a carrot slice.

You will have to play around with the amount of salt you add to the water because all objects have their own unique density. Add salt a tablespoon at a time and mix well until you cannot see any salt in the solution, then add your object to see if it floats or sinks. Remove your object and keep adding salt until you can get your object to float. To make it a true science experiment, create a data table to keep track of how much salt you add to the solution.

The egg floats because the density of the salt water changes to be greater than the egg and the density of the egg becomes less dense so then the egg floats. But when you put an egg in tapwater the density of the egg is greater than the density of the tapwater which makes the egg sink.

Pour 1 tablespoon of salt into one glass, and stir until the salt dissolves. Gently drop a fresh egg into the plain water. The egg will sink to the bottom. Remove the egg and place it in the saltwater. The egg will float. Objects sink in liquids when their density is greater than that of the liquid.

Conversely, objects float when the density of the liquid is greater than that of the object. An egg has greater density than plain water, so it sinks. Salt increases the density of water, however. Density is the mass of a material per unit volume. For example, the density of freshwater under standard conditions is approximately one gram per cubic centimeter. But, if you add enough salt to the water, the egg will actually float back up to the surface! Adding salt to the water increases the density of the solution because the salt increases the mass without changing the volume very much.

When enough salt is added to the water, the saltwater solution's density becomes higher than the egg's, so the egg will then float! The ability of something, like the egg, to float in water or some other liquid is known as buoyancy. But just how much salt is needed to make an egg float? In this science activity you'll figure that out by making solutions with varying concentrations of salt in them.

Observations and results Did the egg float in cup 1 and 2, but not in cups 3, 4 or 5? You likely saw that the egg floated best in cup 1, floated a little less in cup 2 but part of it was above the surface and did not float in the other cups. Cup 1 had the undiluted salty solution that you originally prepared, which was one half cup of salt in two and one half cups water total.

The concentrations of the salt solutions in cups 2 to 4 were halved as you increased in cup number; for example, the concentration of the salt in cup 2 was half that of cup 1, and the concentration of the salt in cup 3 was half again of cup 2. Cup 5 had plain tap water. The egg should have sunk in cups 3, 4 and 5 because the density of the egg was higher than the density of the solutions or plain tap water in those cups. Cups 1 and 2 had more salt in them than the other cups with cup 1 having the most salt , which means these solutions were denser.