 To help a child learn the object's take-up space, you can do a water activity. All you need is a clear container filled halfway with water and some stones. You can mark the water level and then ask the child, what do you think will happen if you put some stones in the water? They can add one stone at a time and see what happens to the water level. When the water reaches the top of the container, you can talk about what they observed. You can explain that when they put the stones in, the water had to move out of the way by moving up higher in the container. This activity helps the child start to understand the idea of volume.