Weigh The Air                      Project Photos>>

• Students will be introduced to the concept that air takes up space and has weight and mass

• This demonstration would fit into a science program for upper elementary or middle school.  Could also be used to practice mathematical concepts of calculating mass.

• Students need to grasp abstract concept of air and how it occupies space

Objectives

• Students will be introduced to the concept that air takes up space and ha weight and mass

• This demonstration would fit into a science program for upper elementary or middle school.  Could also be used to practice mathematical concepts of calculating mass.

• Students need to grasp abstract concept of air and how it occupies space.

Click here for the National Science Standards met by this activity.

Background

We feel air as it blows around on windy days, but otherwise we don't pay much attention to it.  Yet air is really there.  Without it, balloons, birds, and airplanes couldn't fly.  Here's why a plane needs air:  As a plane moves, it pushes air out of the way.  The air moves over the wings.  This moving air actually keeps the plane in the air.

Activity Description

Before beginning this activity, consider the following question.  How much do you think the air in your room weighs?  Choose an answer from the list below before you begin.

• Nothing

• Hardly anything, like a bunch of fluff.

• As much as something I could lift.

• Way more than I could lift.

In this activity, you are trying to find out how air pressure affects objects that are suspended or flying in the air.  The balloons demonstrate what happens and illustrate a principle that will help you understand how planes fly.

Time Required:  10 minutes

Materials

• a measuring stick or tape measure

Teachers Note

This is a good opportunity to have students use teamwork to come up with measurements.  Try having them take a length of string and pull it across the room, then measure the string in segments at a separate work space.

Procedure

1.  First, measure the length, width, and height of the room; then, multiply these amounts together.  This total equals the volume of  your room.  (Estimate the numbers if you can't measure the room.)

2.  A cubic meter of air weighs 1.3 kilograms; a cubic foot of air weights 0.08 pounds.  Therefore, multiply the volume by 1.3 if your measure in meters; by 0.08 if you measured in feet.  The product equals the weight of air in your room.  Surprised?

Discussion Questions

If you can't taste, see, or often even feel air, how can you prove too yourself that it's really there?

Maybe you're convinced that air is stuff, but does it have weight?  If so, how much?  As you'll find out in Weigh the Air the air in one room weights more than you might think.

Now consider this:  It's not just the air in the room that's sitting on you.  It's all the air between you and space.

Assessment

Did students measure accurately?

Did students understand the mathematic calculation needed to understand air mass?

Did the student grasp the concept of air having mass?