Question

why a plastic bottle does float while iron piece of some weight sink​

Answer 1

Answer:

because plastic bottles is light in weight where as iron price is heavier in water

Answer 2

As the density of an iron nail is more than that of water, the nail sinks in water. .....

whereas.. plastic bottles float because plastic is less dense than water. Glass bottles will sink unless they have air trapped in them.....

hope it helps you