Science Project: Salty Water Properties

Items required for this kids science project:

• 1 egg
• 1 large glass or bowl
• salt
• water
• student high power microscope
• depression slide
• cover slip

How does salt change the properties of water? Place a drop of water on a depression slide and take a look at it under the microscope at 100x and 400x magnification. What do you notice? The water is most likely clear and other than maybe a particle or two of dust you shouldn't notice much substance in the water. Try to take a look at single salt crystals as well (when they are not mixed with water).

Place clean water in your bowl or glass and carefully put the egg in the water. Does the egg sink or float?

Salt Crystals captured at 100x under the microscope.

Next, mix 1/2 cup of salt in with your water. Place a drop of water on the depression slide and look at it under the microscope. How was the salt changed the water? What differences do you notice now that the salt has been added to the water?

Carefully place the egg in the salty water. Does the egg float or sink?

Next, take a clean class and pour your salt water half way into the glass. Next, carefully add clean water on the top (trying not to mix the two types of water - do not stir them!)

Salt water is denser than clean water. The denser a liquid is, the easier it is for an object to float in it. When you place the egg in this glass of salt water it lowers through the normal tap water until it reaches the salty water where it is dense enough to float. If you didn't mix the two types of water much when you added the clean water the egg will float in the middle of the glass!