You will need:
To extend the experiment you could try other substances like washing powder, coffee, sand etc.
Science is all about experimenting with different substances to see what happens!
When you add salt to water it makes the water more dense. This means it gets heavier.
Many objects that sink in fresh water will float in salt water!
Objects float in baking soda water because baking soda is a kind of salt.
It dissolves in water to make the water more dense, just like table salt does.
However, baking soda has another property that gave us a little bit of a surprise!
When baking soda dissolves in water some of it reacts to form carbon dioxide gas.
If you look carefully you will see tiny bubbles rising from the bottom of the cup.
Over time the tiny carbon dioxide bubbles attached to the plastic jewels act like tiny life vests that carry the jewels to the top of the cup.