<p>Observing waves in a medium Observing waves in a medium</p><p>To do: To do: . Fill a flat pan about ½ full of water. . Fill a flat pan about ½ full of water. . After you have taken the pan back to your desk, add a . After you have taken the pan back to your desk, add a single drop of food coloring in the center of the container. single drop of food coloring in the center of the container. . At the side of the container, submerge a ruler lengthwise. . At the side of the container, submerge a ruler lengthwise. Move the ruler up and down to make waves. Move the ruler up and down to make waves. . Notice how the waves and food coloring move. . Notice how the waves and food coloring move.</p><p>To think about: To think about: . What caused the wave? . What caused the wave? . Did the waves and food coloring move the same? . Did the waves and food coloring move the same? . What happened to the waves when they hit the sides of the . What happened to the waves when they hit the sides of the container? container?</p><p>How can energy be passed along? How can energy be passed along?</p><p>To do: To do: . Set up dominoes in a line. . Set up dominoes in a line. . Knock over the first domino and notice the motion of the . Knock over the first domino and notice the motion of the other dominoes. other dominoes.</p><p>To think about: To think about: . How far did each domino move? . How far did each domino move? . What traveled from the beginning of the line to the end of . What traveled from the beginning of the line to the end of the line? the line? . Where did the energy to move the last domino come from? . Where did the energy to move the last domino come from? . How is this related to waves? . How is this related to waves? Slinky motion Slinky motion</p><p>To do: To do: . Stretch out the slinky on the table until it is about 1 meter . Stretch out the slinky on the table until it is about 1 meter long. long. . Hold one end of the slinky firmly and quickly push in the . Hold one end of the slinky firmly and quickly push in the other end about 10 cm. other end about 10 cm. . Notice how the disturbance moves down the slinky. . Notice how the disturbance moves down the slinky.</p><p>To think about: To think about: . What moved? . What moved? . Does the pulse depend on how tightly you stretch the . Does the pulse depend on how tightly you stretch the slinky? slinky? . How did the position of the coils change? . How did the position of the coils change? . How is this wave different from other waves? . How is this wave different from other waves?</p><p>Ripples on water Ripples on water</p><p>To do: To do: . Fill a bowl half-full of water. Fill a pipette with water. Take . Fill a bowl half-full of water. Fill a pipette with water. Take both back to your desk. both back to your desk. . Drip single drops of water in the center of the bowl using . Drip single drops of water in the center of the bowl using the pipette. the pipette. . Notice the motion of the waves. . Notice the motion of the waves.</p><p>To think about: To think about: . What does it look like if you make drops in more than one . What does it look like if you make drops in more than one place? place? . Does it make a difference if you drop two drops in at the . Does it make a difference if you drop two drops in at the same time? same time? . How are these waves similar to and different from other . How are these waves similar to and different from other types of waves? types of waves? Make a wave Make a wave pulse pulse</p><p>To do: To do: . Barely stretch the . Barely stretch the elastic string between elastic string between two chairs, as shown. two chairs, as shown. . One partner should pull . One partner should pull the string down about the string down about 10 cm and release it. 10 cm and release it. . Observe. . Observe.</p><p>To think about: To think about: . What moved down the string? . What moved down the string? . How is the motion of a wave pulse different from other . How is the motion of a wave pulse different from other kinds of motion (like a car)? kinds of motion (like a car)? . What happens to the wave pulse when it hits the other end . What happens to the wave pulse when it hits the other end of the string? of the string? . What changes if you stretch the elastic more or less? . What changes if you stretch the elastic more or less?</p><p>Phone cord slinky Phone cord slinky</p><p>To do: To do: . Stretch out the phone cord on the table. . Stretch out the phone cord on the table. . With one person holding the end firmly, the other end . With one person holding the end firmly, the other end should be shaken to produce waves. should be shaken to produce waves. . Notice the effects of shaking it faster and slower. . Notice the effects of shaking it faster and slower.</p><p>To think about: To think about: . What caused the wave? . What caused the wave? . What happens when both ends are moved at the same . What happens when both ends are moved at the same time? time? . Is the wave different if it is looser or stretched more . Is the wave different if it is looser or stretched more tightly? If it is shaken faster or slower? tightly? If it is shaken faster or slower?</p>