In this lesson plan, adaptable for grades 5-8, students play Hot Air Balloon, a simulation game that challenges students to use their knowledge of buoyancy and gravity to keep a hot air balloon flying as long as possible. Through play, students explore and deepen their understanding of the relationship between temperature and volume as well as volume and density.

### Students will:

1. Explore the relationship between temperature and volume as well as volume and density.
2. Understand that buoyancy is the force created by denser air pushing less dense air upward.
3. Experiment with weight difference, wind speeds, and limited fuel to make a hot air balloon rise higher.

### Materials:

• Computers or other devices with Internet access
• Interactive whiteboard
• Pictures of hot air balloons in the air

### Vocabulary:

buoyancy, altitude, density, acceleration, velocity, force

### Preparation:

This lesson plan features a game called Hot Air Balloon developed by our partner,  Field Day Lab. The game is a simulation in which students apply their knowledge of force and gravity to control a hot air balloon and observe how wind, temperature, and weight affect the balloon’s buoyancy.

Display the pictures of hot air balloons (see Preparation) around the classroom.

Preview and play Hot Air Balloon to plan how you will adapt it to your students’ needs. If students will be playing in small groups, review tips on Setting Cooperative Gaming Expectations.

Depending on your classroom routines and available technology, you may want to consider these grouping options:
• 1:1 with students and devices
• Two to three students sharing one device and swapping ideas and the device back and forth
• Station model where small groups rotate through using the devices
Build background knowledge or reinforce topics with these BrainPOP movies: Buoyancy, Gravity, Force, Temperature, Heat, and Wind

### Lesson Procedure:

1. Ask the class what they think buoyancy means. Jot their responses on the board or chart paper. Then build students knowledge of this concept by playing the BrainPOP movie Buoyancy for the whole class on the whiteboard or other display. After watching the movie, ask students how buoyancy might apply to objects in the air.
2. After everyone shares their ideas, draw their attention to the pictures of hot air balloons you’ve displayed around the classroom. Ask what hot air balloons have to do with buoyancy. Allow students to respond, then explain that hot air rises the balloon as a result of buoyancy, and that the difference between the outside and inside air determines the hot air balloon’s buoyancy.
3. Project the game Hot Air Balloon on the whiteboard or other display. Tell students that in this game, they will control the altitude of the balloon by heating the balloon or releasing air from the air flaps. Other factors they will need to consider are weight difference, wind speeds, and limited fuel.
4. Using the “Free” mode, demonstrate the features of the game and how it works. Model how to click and hold the “burn” button to fill the balloon with hot air, and show how to release air by clicking the “open flap” button. Demonstrate how clicking the eye icon on the right side of the screen allows players the option to display particles and arrows. Ask students what they think the particles and arrows represent. Also ask how and why they change as the balloon heats up.
5. Now direct students’ attention to the gauges at the top of the screen. Ask what happens to the gauges as the balloon heats up and why this happens. Model how to change the variables including outside temperature, balloon temperature, and volume by clicking the gauges.
6. Divide the class into pairs or small groups to play Hot Air Balloon game. Instruct them to select the “standard” mode. Circulate as students play and help as needed. Listen to students discuss their strategies for how to make their balloons go far. If students have individual logins through My BrainPOP, encourage them to use the SnapThought® tool to take snapshots and notes describing what happens when they manually change the outside temperature, balloon temperature, and volume. Ask them to explain what happens when the balloon gets heavier and lighter. Prompt them to take snapshots showing how each variable affects the balloon and write why these changes happen.  For suggested prompts, see Hot Air Balloon: Additional Features for My BrainPOP.  If your students don’t have the SnapThought tool, they can take notes offline.
7. Bring the class together to discuss what they learned about buoyancy, altitude, density, acceleration, gravity, and velocity.
8. Conclude the lesson by inviting partners or groups to have a competition of who can make their balloons fly the farthest. Keep track of high scores on the board as students experiment with the variables. Remind them to use what they learned about temperature and volume to create ideal conditions for their hot air balloons.

### Extension Activities:

Show what you know about buoyancy by completing the Buoyancy Activity.