# What is the Volume?

By Susan LoFranco on Apr 24, 2017

• Students will use the formulas for perimeter, area, and volume to solve real-world and mathematical problems. • Understand what cones, cylinders, rectangular prisms and spheres are, including where length, width, height, and radius are on those figures.
• Relationship between the Value of Pi and the diameter and radius of a sphere.

## Procedure

Definitions: cones, cylinders, spheres, rectangular prism, value of Pi, circumference, radius, diameter, volume, length, height, width, base

• Review with student(s) the different objects you have collected (one of each cone, cylinder, sphere, and rectangular prism).  Once the student is fully able to identify all the objects choose one item.  Starting with the cylinder ask the student to tell you what they know acount the (can of soup, tomatoes etc).  They should be able to identify the base and the sides which represent height.  Have the student measure the base and the height recording their answers in the students media of choice.
• Together, using the appropriate formula, calculate the volume of the cylinder.  Using the Volume Task Worksheet have the student explain how they determined the volume.  Challenge the student to explain why they are correct.
• If the student is confident they can move on to the next object and calculate the volume of the remaining items.
• If further help is needed ask guiding questions such as: What do you know about the object?  What can you measure?  How does this help in calculating volume?
• The Volume Task Worksheet will act as your assessment and should be completed with time permitting. Encourage the student to answer in complete sentences. ## Variations

• If the student does not understand the relationship between circumference, diameter, radius and the value of Pi it can be discovered by having the student measure the circumference of a can then measuring the diameter the can.  If no tape measure is available us string to measure circumference then measure that length against a ruler.
• Converesly have the student measure the diameter of a can with a piece of string and then see that the piece of string will need to go around the circumference of the can a bit more than three times.

Pi equals the circumference divided by the diameter.  It should be roughly 3.14

• When calculating the volume of a sphere if the diameter is unknown have the student measure the circumference then divide that value by Pi to determine the diameter, then divide the diameter by 2 to determine the radius.

Extra practice online can be found at the following website: http://www.ixl.com/math/grade-8 or by using the Volume Additional Practice Worksheet.  Volume Formulas.doc, Volume Task.doc, Volume Additional Practice.jpeg