# 1 Dec Sci 7 — Continue hot air balloon construction

Each group has a “captain” who will first receive instructions and will then deliver instructions to the respective group.

We should be able to finish most balloons today so that flights can begin in the next class–that is, if groups work efficiently.

Think of what you will observe. Think of what could be happening when we heat the air inside the balloon. (We will use devices called “heat guns” that are like super-charged hair dryers.)

Your summative will involve in class writing after we have spent a class or two observing flights, proposing explanations, examining relationships (how does heating time relate to the time it takes to reach a certain height, for example), testing explanations, exploring the parameters of performance (how fast, how far, how strong, etc).

Here are the questions for our Energy summative. Everyone will answer #1 and everyone will choose 1 more to answer from choices #2, #3, #4, #5, and #6.

1. Energy is the capacity to do work. Work occurs whenever a force is applied to a mass through some distance. One form of energy can be transformed into another form. The total energy in a closed system is conserved. Describe as many energy transformations as you can (that are associated with the launch and flight of a hot air balloon–like one we have flown). What forces are applied to what masses? Be sure to discuss how heat energy is involved? You may include labeled diagrams/sketches.
2. Describe the “best” launch and flight of your balloon. Define “best.” Describe features of your balloon. You may include labeled diagrams/sketches.
3. Describe the way the surface temperature of the hot air balloon changes during the operation of the heat gun and during the flight and landing. What do you think happens to the air during each phase? If you could see the molecules of air during the heating, flying and landing, how do you think they would look? You may include labeled diagrams/sketches.
4. What was your “first” explanation of why the balloon “flies?” What was a different explanation offered in your class for why the balloon “flies?” You may include labeled diagrams/sketches.
5. What experiment/test was performed to test your explanation of why the balloon flies? What were the results? What conclusions? You may include labeled diagrams/sketches.
6. What experiment/test was performed to test a different explanation? What were the results? What were the conclusions? You may include labeled diagrams/sketches.

A video clip of a launch: https://drive.google.com/a/aes.ac.in/file/d/1RzPpRbWxpCUi5CElcH4I9ayY_ZFys-WM/view?usp=sharing