My third graders are currently learning volume. They've already done perimeter and area, but volume is really a hard concept for them. The kind of stuff we have to work with is basically, "Look at the picture. How many cubic units does it take to make it." I've given the kids connecting cubes and we have recreated the figures very slowly and step-by-step as a class. We've talked about the different layers of a figure, and how cubes can't just float (there needs to be a cube underneath it if it's not on the bottom). Right now things just aren't clicking with them. It's a hard concept to visually move a drawing on paper in all dimensions, and if they can't see all the cubes, they struggle with knowing that they are indeed there. I can certainly understand why they are having trouble. Does anyone have any good ideas for helping teach this challenging concept? I hate seeing the frustration on their faces, and I want to make this as engaging and understandable as possible for them.