Name _________________
Period: 1 2 3 4 5 6 7 8
PHET wave simulations
Part 1: Microwaves
This simulation represents the inside of a microwave. You are able the see the electromagnetic microwaves
(green line), and to see the water molecules that are in the microwave (blue and red objects).
-Begin with a single line of molecules and use the “line” field of view. Leave all of the other default settings on for
now.
- Turn the microwave on by pushing the “microwave on/off” button, and carefully observe what happens.
1- What happens to the wave (green line)?
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2- What happens to the water molecules (blue and red particles)?
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3- What happens to the temperature (you can observe the temperature by looking at the red thermometer on the
left side)?
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- Now pause the microwave using the pause button on the bottom of the screen. Turn the frequency all the way
up by sliding the “frequency” slider arrow (on the right side of the screen) all the way to the right. Before you
unpause, make a prediction about what you think will happen now that you have increased the frequency of the
wave.
Predictions:
4- I think that the wavelength will __________________ (increase or decrease).
5- I think that the temperature will ____________________(increase or decrease).
6- I think that the speed of the molecules will _________________________(speed up or slow down).
- Test your predictions. Unpause the microwave by hitting the “play button at the bottom of the screen. Let the
microwave run at this higher frequency for about one minute, then pause it again and see how did with your
predictions. What happened to each of the following items:
7- The wavelength _________________________________________________________.
8- The temeperature ________________________________________________________.
9- The molecules ____________________________________________.
- Now, hit the reset button to put everything back to the starting point. Then increase the amplitude of the wave
by sliding the “amplitude button”, (located on the right side of the screen underneath the frequency slider
button) all the way to the right. Before you start the microwave, predict what will happen now that you have
increased the amplitude:
10- I think that the wavelength will _________________________________________
11- I think that the temperature will ________________________________________
12- I think that the molecules will ____________________________________________
- Test your predictions by turning the microwave on. Let the microwave run at this higher amplitude for about
one minute, then pause it, and see how you did with your predictions:
13- The wavelength _______________________________________
14- The temperature _____________________________________________
15- The molecules ________________________________________________
16- How did changing the amplitude change the wave?
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- Now experiment with how changing the number of molecules, but clicking the links at the top of the page that
say
“one molecule,” “single line of molecules,” and “many molecules”.
17- How does changing the number of molecules affect the temperature (assuming that you keep everything else
the same?)
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- Observe carefully what happens to the speed of the molecules when the temperature increases.
18- How are temperature and the speed of molecules related (inversely, directly, or not related)?
___________________________________________________________________________________________Graph the relationship in the space provided below:
19- How are frequency and wavelength of the microwave related (inversely, directly, or not related)?
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Graph the relationship in the space provided below:
20- How are amplitude of the wave and temperature related (inversely, directly, or not related)?
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Graph the relationship in the space provided below:
21- How are wavelength and energy related (inversely, directly, or not related)?
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Graph the relationship in the space provided below:
22- What are 3 things that you could do to make the highest possible temperature inside the microwave?
a.
b.
c.