## It Won't Budge: Balloon

### Summer ZephyrBay District Schools

#### Description

Through use of a "silent teacher" demonstration, students use the scientific method to discover the principle behind the balloon not being inflated.

#### Objectives

The student extends and refines use of systematic, scientific processes to develop and test hypotheses.

#### Materials

-Rubber balloon
-Plastic soda bottle
-Air from your lungs
-Student Assessment Sheet (in associated file)

#### Preparations

1. Gather soda bottle, three balloons per class.
2. Understand this background information:
Air pressure is the weight of the atmosphere pressing down on the earth. It is measured by a barometer in units called millibars. Most barometers use mercury in a glass column, like a thermometer, to measure the change in air pressure.
When the weather is calm the mercury in the barometer seldom moves more than half-an-inch below the 30-inch mark.
If a high pressure system is on its way, often you can expect cooler temperatures and clear skies. If a low pressure system is coming, then look for warmer weather, storms and rain.
The weight pressing down on a one square-inch sample of air at sea level is 14.7 pounds, which is equivalent to a column of mercury 29.92 inches in height (1,000 millibars).
Air pressure changes with altitude. When you move to a higher place, say a tall mountain, air pressure decreases because there are fewer air molecules as you move higher in the sky
Mass: The quantity of matter as determined from its weight or from Newton's second law of motion. Abbr.: m Cf. weight
Volume: The amount of space, measured in cubic units, that an object or substance occupies.

#### Procedures

1. Review with students the defintion of the concepts of air pressure, volume, mass.

2. Teacher has before him an empty soda bottle with the cap off, and a deflated balloon and asks students the following questions and allows discussion:
What do you think I am going to do with this equipment?
Is this bottle empty?
How do you know it is empty?
How can you tell if something has mass?
Ask students what they think will happen if I put the balloon in the bottle and try to blow it up. (hypothesis)

At this time, hand out the Student Assessment Sheet and go over it with students.

3.Give a "silent demonstration" of the concept of air having mass by silently demonstrating the following air pressure principle.
Demo: Place balloon inside a pop bottle.
Fold opening of balloon around mouth of the bottle.
Blow up balloon (or at least try)

4. Have two other students try to blow it up using a new balloon of the same type (for sanitary reasons).

5. Ask students for their conclusion.

6. Ask students from their observation, why they think the balloon was unable to be blown up.

7. At this time, ask students to complete their Student Assessment Sheets.

8. Bring students back together to discuss the results. Allow those who are having difficulty time to reflect on the discussion and change their lab sheets. Ask students to determine additional experiments that might help support their conclusions.

#### Assessments

Use the Student Assessment Sheet in which students use the scientific method to determine if air has mass as an assessment. It is in the associated file.

#### Attached Files

A Student Assessment Sheet and answer key.     File Extension: pdf