What does water do when a solid object is put into it? Does it make room by making its molecules crowd together? Does it shrink somehow? Does it just get out of the way?

We have a glass measuring graduate, half-filled with water. We will carefully drop in a rock, and we will see what the water does. It certainly didn't shrink, did it! It got out
of the way. We can see that the water is now above the 1/2 mark on the graduate.

Does that mean there is more water? The same amount of water is in the cup. The water was displaced by the rock.

Let's try it with a marble or a nail.

What can we tell about the solid objects that we have put into the water? We can tell the volume of the solid object, even if it is irregular in its shape.