Volume and Weight
things that are the same size but can weigh differently.
a big balloon filled with air, and rabber ball that's the same size.
They look the same in size, right?
But if you pick them up, you'll notice something different.
The balloon is very light because air is not heavy at all.
But the rubber ball is much heavier because rubber is denser than air.
So, even though they are the same size, they can weigh differently.
