Step 2: Teach Lesson
Volume is measured in cubic units, which means it tells how many cubes of a given size it takes to fill the prism. The formula for
volume of a right rectangular prism is length x width x height. The formula for volume of a right prism with a triangular base is 1⁄2
(length x width) x height.
Read the book, Counting on Frank
, to your student. Discuss all of the different things the boy measures in the book. Define volume
and look in the book for all of the ways the boy finds volume – 24 Franks in his bedroom, ten humpback whales in the house, 1/10 of
his dad in the portable television, peas in the dining room, and 745 jellybeans in the jar. Have the student write a summary about
Frank and his “pet” boy. Have the student pick a new object and write how many of those objects they think it would take to fill their
bedroom. Have the student share the ideas. Explain that we don't usually measure volume in Franks, humpback whales, peas, or
jelly beans; instead, we use cubic units to measure volume.
Give your student the Let’s Build Boxes (Step 3)
. Explain to the student that they are part of a company that builds boxes. Their
department is in charge of making the bottom part of the box. They need to make different size boxes and determine how much each
box can hold, or the volume of that box.
Give the student 4 pieces of two-cm graph paper. Hold up a sheet of graph paper and demonstrate how to trim it to a 9 x 11
rectangle. Have the student trim each sheet of graph paper to a 9 x 11 rectangle. Ask the student how many unit squares they have
on each sheet. Make sure they understand that each sheet has 99 unit squares.
Hold up a sheet of trimmed graph paper and cut one unit square from each corner. Fold up the outside rows to make a box. Tape the
corners. Tell the student to do the same thing to one of their papers. Then have the student use multilink cubes to fill the boxes.
Discuss their findings. What strategies were used to figure out how many cubes were needed? Did the entire box need to be filled
with cubes before knowing how many would be needed?
Have the student fill in the information for Box 1 on the Let’s Build Boxes
assessment. You may need to fill in the data for the first box