There is lots of fun to be had testing to see what materials float and what sinks. You can do this at bath time or just with a large tub of water. Have competitions to see who can guess right, what will float and what will sink before you test it. You can also test how many toys can you get on your boat before it sinks.
Ask the big questions… how does a ferry float as it is far heavier than a stone – which sinks?!
And why does some wood float and some sink?
The lesson plan and more ideas can be found here:
A link to the story can be found here