Radiation Answer Key
Vocabulary: filament, infrared, Kelvin scale, radiation
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
[Note: The purpose of these questions is to activate prior knowledge and get st
...
Radiation Answer Key
Vocabulary: filament, infrared, Kelvin scale, radiation
Prior Knowledge Questions (Do these BEFORE using the Gizmo.)
[Note: The purpose of these questions is to activate prior knowledge and get students thinking.
Students are not expected to know the answers to the Prior Knowledge Questions.]
1. The Sun is millions of kilometers away. How can heat from the Sun get here?
Answers will vary. [In fact, the Sun is so hot that it glows, and that light (radiation) heats the
Earth.]
2. If you look inside an electric stove or toaster oven, how can you tell whether it’s turned on?
The burner or heating element will glow. [These items glow because they are very hot, just
as the filament in an incandescent bulb does.]
Gizmo Warm-up
In the Radiation Gizmo, you can focus the light of a super-powerful
flashlight upon a kernel of popcorn and see what happens. The
lens, which focuses the light, can be moved to the left or right.
1. The Temperature slider controls the heat of the metal filament
inside the light. Scientists use the Kelvin scale to measure the
temperature of a light filament. It is like the Celsius scale except
0 K (absolute zero) is the coldest anything can ever be.
Slowly move the Temperature slider all the way to the right. What happens?
The color of the light changes from red to orange to yellowish-white.
The light energy emitted by the flashlight is called radiation.
2. Slide the lens so the distance to the flashlight is 40 cm. Press Play ( ). What happens?
The kernel pops. [It takes 1.2 seconds to pop at the maximum temperature.]
3. Do you think the kernel will pop if you place cardboard in front of the flashlight? Predictions
will vary.
4. Click Reset ( ). At the top of the Gizmo, next to Obstacle, select Cardboard. Press Play.
What happens? Nothing—the kernel never pops.
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