Volume of Spheres, Day 2

Warm Up

All cross sections of a sphere are circles and all points on the surface

of a sphere lie at the same distance, called the radius, from

the center.

An ice cream shop has a model of an ice cream cone with a spherical scoop of ice cream on top of the cone. The

diameter of the sphere and the cone is 6 inches. The cone is 9 inches tall. Ask students to find the volume of the ice

cream cone model to the nearest tenth.

How do you find the volume of a sphere?

Find the product of , the cube of the radius, and ∏.

What do you need to know about a sphere to be able to calculate its

volume?

You need to know the radius or be able to determine the radius from

the diameter or the circumference.

A steel ball bearing has a diameter of 1.6 centimeters. What is the volume of this steel ball? Round

your answer to the nearest tenth if necessary. Use 3.14 for ∏.

A spherical helium balloon that is 8 feet in diameter can lift about 17 pounds. What does the diameter

of a balloon need to be to lift a person who weighs 136 pounds?

Explain.

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