Use Proportional Reasoning

The 1963 Buick Riviera

Use the information provided to make, from clay, an accurate model of the car at 1/64 scale.

Get the Activity

Battle of the Batteries

The capacity of a battery is the quantity of electrical current it can produce for a length of time, measured in a unit called “milliampere hours” ( abbreviated as “mAh”). This determines how long the battery lasts.

Get the Activity

Counting Blood Cells

Sometimes doctors need to know how many of a certain kind of cell is in a drop of someone’s blood. Here’s something you can do to show you how they find this out.

Get the Activity

Counting Cars

Think of a way you could estimate the total number of cars that travel on the street in front of your school all day. Write down your plan and show it to your teacher.

Get the Activity

The Forest and the Trees

Forest ranger Arnold Wilson wants to plant three kinds of trees on a mountain: Ponderosa Pine, Douglas fir, and White Fir.

Get the Activity

How Tall?

Find the heights of people and things with a little proportional thinking.

Get the Activity

Ladybugs

"What? Growing bugs is a real job? And it requires math?"

Get the Activity

Mission to the Moon

For the orbital motion of the moon, we use the fact that the moon completes one orbit (360°) every 655 hours to set up the proportion h/655 = n/360, where h = the number of hours that have passed and n = the number of degrees that the moon has moved in its orbit.

Get the Activity

Snow

Snow takes up a lot more room than the same amount of liquid water. For some kinds of snow, it can take 10 inches of snow to equal 1 inch of liquid water.

Get the Activity

Timber Cruise

Using a sample of tree heights and diameters, this lesson gets students to see how foresters use problem solving to get an accurate estimate of the total volume of wood in a forest.

Get the Activity