Water Float

What is a really heavy bouyant object that will still float in water?

I’m doing a competition for my science class and I need some help finding the heaviest possible object that will float in a cooler in a tub of water.
PLEASE HELP!!
Thanks

Can you make it? We made ships out of foil in our class one year, it can hold like 90 pennies, which is heavy! test it at home before you go! good luck girl(:!

Freestyle Swimming Techniques : How to Float in Water

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