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)? _____________________________________________________________________________________________ _________________________________________________________________________________________ 2- What happens to the water molecules (blue and red particles)? _____________________________________________________________________________________________ _________________________________________________________________________________________ 3- What happens to the temperature (you can observe the temperature by looking at the red thermometer on the left side)? _____________________________________________________________________________________________ _________________________________________________________________________________________ - 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? __________________________________________________________________________________________ - 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?) _____________________________________________________________________________________________ _________________________________________________________________________________________ - 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)? ___________________________________________________________________________________________ Graph the relationship in the space provided below: 20- How are amplitude of the wave and temperature related (inversely, directly, or not related)? ___________________________________________________________________________________________ Graph the relationship in the space provided below: 21- How are wavelength and energy related (inversely, directly, or not related)? ___________________________________________________________________________________________ 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.