The concept of density is quite interesting to explore and there are a ton of experiments for it!
Here is a simpler experiment to understand how salt affects density of water.
What you need:
– 2 large bowls
– Water
– Salt
– Objects of varying weight
Steps
Add the same amount of water to both the bowls. Then add some salt only to one of the 2 bowls. Place the objects, one by one to see if they float or sink.
Ask the kids to observe if objects are floating better on saline water or not.
What happening here is that salt adds to the density of water and the objects float better!