 ### Overview

Students will determine whether the amount of air in a balloon changes the distance it will travel on a fishing line. They will collect data from multiple tests and then create a graph to visualize the variation.

### Management

• This activity can be done as an extension of Simple Rocket Science.
• Set up the fishing line, straw and balloon as noted in Simple Rocket Science.

### Background

NASA uses rockets to launch satellites and probes into space. NASA rockets are powered by burning solid, liquid or gas rocket fuel.

Long before the development of modern rockets, Sir Isaac Newton described the principles of rocket science in three laws of motion.

A simplified explanation of his third law of motion helps young students understand how rockets work. This law states that every action has an equal and opposite reaction.

When a rocket expels fuel or propellant out of its engine, the rocket moves in the opposite direction. The rocket pushes the propellant out, and the propellant then pushes the rocket. The propellant comes out of the engine; this is the action. The rocket lifts off the launch pad in the opposite direction; this is the reaction.

In this activity, the rocket is a balloon propelled by air. The greater the propellant, the greater the action and thus, the greater the reaction. Students will experiment with different amounts of air and measure the distance the rocket travels.

### Procedures

1. Set up the experiment as described in Simple Rocket Science. Discuss with students what they learned from the experiment in Simple Rocket Science.
2. Explain to students that in this lesson, the balloon experiment will also be repeated several times. Let students know there will be one difference in the experiment this time. Each time the class conducts the experiment, there will be a different amount of air in the balloon, and we will keep track of the results.
3. Draw a vertical line on chart paper to create two columns. Label the two columns “Number of Breaths” and “Distance Traveled.” For non-readers, drawings may be more appropriate than words for the column titles.
4. Blow up the balloon using one breath or stroke of the balloon pump.
5. Place a “1” on the chart under “Number of Breaths.”
6. Ask students to determine from where we should launch the balloon (far to one end of the fishing line). Mark the location of the front of the balloon on the floor to indicate the launch point.
7. Launch the balloon.
8. Once the balloon comes to a stop, mark the location of the front of the balloon on the floor.
9. Have a student use interlocking cubes (or any nonstandard measurement device, such as one of these paper rockets) or a ruler to measure how far the balloon traveled from its starting point. Remind students to use the unit of measurement when they talk about the distance traveled. For example, “The balloon traveled a distance of 17 cubes.”
10. Record this measurement on the chart under “Distance Traveled.”
11. Ask the students what they think will happen if we use two breaths.
12. Perform the experiment using two breaths and record the measurement.
13. Continue performing the experiment for more breaths.
14. Ask students to estimate how far 10 breaths would take the balloon. Have them give reasons for their estimates.
15. Perform the experiment and determine how close students’ estimates were.
16. Repeat the experiment to verify data and repeat with other numbers of breaths.
17. Create a pictograph for each number of breaths used, using a symbol (such as a drawing of a rocket) to represent the distance traveled for each.
18. Ask students what they learned during this experiment. Answers will vary but might include: More air makes the balloon go farther. Consistency in airing up the balloon is important. Measuring accurately is important.

### Assessment

• Evaluate students’ ability to use non-standard measurement tools to accurately measure distances.
• Evaluate students’ ability to predict based on data.
• Ask students to draw a picture of the experiment in their journal or on a sheet of paper. Ask them to write a sentence about the results of the experiment or describe the results orally. Evaluate.

### Extensions

• Repeat the experiment using groups of five interlocking cubes as a nonstandard measuring tool. Students gain experience counting by 5s.
• Repeat the experiment and measure using a different size rocket. Compare the results.
• Encourage students to think of other forms of nonstandard measurement to determine the distance the balloon traveled. Use one or more of their suggestions and repeat the experiment.
• Set up two balloon experiments side by side in the classroom. Let the students “race” two balloons at one time. Vary the number of breaths in the balloons. Let students count the number of breaths and measure the distance the balloons travel.
• Have students apply what they learned in this experiment. Ask students to consider whether the amount of fuel in a rocket determines how far it travels. Ask students to consider other factors such as size and weight that may affect the distance a rocket travels.
• Encourage students to look at the depictions of rocket launches and think about what they now know about how a rocket works.