# Volume of 3D Shapes with Play-doh

When my students are excited about what they are doing in class, they are engaged.  They will listen and best of all, learn.  The kids were ecstatic when they saw the Play-doh.  They couldn’t wait to get their hands on it!  The benefits for learning were amazing.  All I had to say was “Remember the Play-doh?” and they knew what to do for any volume problem.

Supplies per student:

• One fun-sized Play-doh
• Ruler
• Plastic knife
• Ruler

Instructions:
Many of my students had heard somewhere along the way that volume equaled length times width times height.  So, I started by having them make a rectangular prism out of their Play-Doh.

Once it was made, I had them draw a picture of it in their Geometry Booklets.  Then they measured and recorded the length, width, and height of their prism in centimeters.  Next, I had them cut their prism into 1 centimeter lengths.  They observed that the cross sections were squares.  I had them find the area of this square.  We talked about how many slices they had.  So if their area was 6 centimeters squared and they had four slices how could they find the volume of the box?  They quickly deduced that they needed to multiply the 6 by 4 to arrive at 24 cm cubed.

I repeated this for a cylinder and a triangular prism.  We observed what the cross sections were, found the areas of our cross sections, and then found the volume.  To sum it all up, we talked about how volume of a prism or cylinder is the area of the base (cross-section) times the height (number of slices).

It was so much fun!