homework

1) n the simulation, you can see a top view, side view, and graph of this scenario. Use the simulation to create a pattern similar to the one at the right. Describe what is happening in the simulation to create this pattern.link see below https://phet.colorado.edu/sims/html/wave-interference/latest/wave- interference_en.html ) Challenge Question: Obtain a pan and fill the pan with water. Try to produce the pattern and describe the method you used for producing the pattern. note: The part with the pan is a challenge question. Any credit earned here is extra credit and you may skip the pan experiment without penalty. 2) The diagram shows the locations of the wavefronts at one instant in time, as a photograph would. How, if at all, would the diagram differ: one-quarter period later? Explain. one period later? Explain. Be sure to describe both cases and remember that the period is the time from one wave crest to the next wave crest. 3. Using the simulation, try to produce the pattern above again but this time create a pattern with a smaller wavelength. How did you do it? What did you change in the simulation to shorten the wavelength? How would you produce a pattern with a larger wavelength? Challenge question: Try to produce the pattern with a shorter wavelength in your pan of water. How did you do it? 4.) Using the simulation, try to produce the pattern above again but this time create a pattern with a smaller wavelength. How did you do it? What did you change in the simulation to shorten the wavelength? How would you produce a pattern with a larger wavelength? Challenge question: Try to produce the pattern with a shorter wavelength in your pan of water. How did you do it?

5) Periodic circular waves: two sources


The diagram at the right illustrates the wavefronts due to each of two small sources. Click on the “Interference” tab of the simulation found at the bottom of the window and produce this pattern with water. Explain how you did it. Challenge Question: Try to produce this pattern in your pan of water. Explain how it worked with an actual pan of water.   7)   Each of the photographs shows a part of a ripple tank that contains two sources that are in phase. The nodes are those places in the pattern where the surface of the water is at equilibrium level, neither peaks nor troughs. For each of the photographs, identify the lines of nodes.

How many nodal lines are there in the picture at left? (Ignore the horizontal ones for now.) Answer

How many nodal lines are there in the picture at left? (Ignore the horizontal ones for now.) Answer 8)what difference(s) in the two situations could account for the difference in the number and the locations of the lines of nodes? Play with the simulation to try to reproduce each picture. Describe what worked to increase the number of lines of nodes. 9) In the simulation there are buttons to switch between water waves, sound waves and light waves. The buttons are in the upper right menu box under the slider that adjusts separation. View the simulation for sound waves and light waves. How do the patterns for water waves, sound waves, and light waves compare?

12) Observe: Use the water-level indicator graph in the simulation to test your predictions. The water level indicator is in the row of tools in the top right, the one furthest to the right. Set up the two probes at two crests in the paused simulation and then start the simulation and watch what happens to the water level at the two points.   13) Pause the simulation and move the probes to two nodes. You can tell when you are exactly at the node because the dot on the graph will be at the center of the chart.

Restart the simulation. Describe what happens to the height of the water at the point of the two nodes over time. 13) 14) Suppose that a small leaf or bug were floating on the surface of a pond. Use your diagram to predict where it would move

1. the least and 2. the most.

Enter your predictions in the text box below.