Volume (3D)

What is volume?

Volume is how much space something takes up. It is the amount that fits inside a box.

You measure volume in cubic units. A little cube that is 1 unit on every side holds one cubic unit.

Think about a moving box. Volume tells you how much you can pack inside.

What is this module?

The module shows a box you can spin around. Three sliders control the length, the width, and the height.

Move the sliders and the box grows or shrinks. The volume updates as you go. It is length times width times height.

What they're learning

• That volume comes from multiplying the three edge lengths.
• That the order of the multiplication does not matter.
• That volume is measured in cubic units, not square units.
• That a box with equal edges is called a cube.

Aliases

• Volume
• Rectangular prism
• Length × width × height
• Cubic units

Refresher

Volume is how much space a box takes up. You find it by multiplying length, width, and height, and you measure it in cubic units.

Try this together

You don't have to teach a whole lesson. A few minutes with the sliders is enough.

1. Set length 5, width 4, height 3. Ask your kid to guess the volume before checking.
2. The readout shows 60. Work through it together: 5 × 4 = 20, then 20 × 3 = 60.
3. Set all three to 6. Ask what shape it becomes. It is a cube, and the volume is 216.
4. Go back to 5, 4, 3 and double all three edges. Ask whether the volume doubles. It multiplies by 8.

If you're stuck, start with one layer. Length times width gives the layer, and the height stacks the layers.

Words you might hear

• Volume: how much space a shape takes up.
• Rectangular prism: a box shape with flat rectangular faces.
• Edge: one of the sides of the box.
• Cubic units: the unit for volume. A 1 × 1 × 1 cube is one cubic unit.
• Cube: a box where all the edges are equal.

Deeper dive

For a 5 by 4 by 3 box, start with one layer. Length times width is 5 × 4 = 20 cubes in the bottom layer. The height of 3 stacks three layers, so 20 × 3 = 60 cubic units.

The order of the multiplications does not matter, since 5 × 4 × 3 and 3 × 5 × 4 both give 60. A box with all edges equal is a cube, and doubling all three edges multiplies the volume by 8.