This is a very simple experiment looking at water tension!
What you will need:
A big bowl of water
Some ground pepper (black so you can see it) or any other ground product with colour
Some washing up liquid
Let the water go still and sprinkle you ground pepper over the top
In the middle of the bowl drip some washing up liquid and watch the effect!
You should see a ‘hole’ starting to appear in the centre and the pepper moving outwards as it gets bigger!
The Science Bit!
The hole is caused by the soap breaking the surface tension of the water, then the tension of the rest of the water pulls the floating pepper away from the soap!