I call students to the gathering area. I tell them that today we are going to look at waves some more. We are going to build our own wave machine using duct tape, kebob skewers and gum drop candies. I answer the myriad questions that arise from this announcement.
Together we make a space in the classroom between two tables or two stools. We stretch duct tape between them with the sticky side down. We place skewers across the tape on the underside, evenly spaced down the entire length of the tape. We then place a gum drop candy on both ends of each skewer. From this we can make different types of waves. Students can see the propagation of waves and how they move back and forth. The gum drops are relatively heavy so the waves move back and forth relatively well and for a good length of time.
Students can play with standing waves, which is when you move the first skewer up and down different amplitudes so that different size waves move up and down the tape. This causes a stop in the movement of the waves as the different waves move in opposite directions and cancel each other out.
After the structured investigation, I let students try different things out with the wave machine. This often leads to some very interesting discoveries and students begin to talk about differences in frequency and amplitude and how these might work in real life.
I call students back to the gathering area where we talk about what we learned today. I ask students about any “aha” moments they may have had today and if there were any questions that arose from their investigations.
Students write a reflection in their science notebooks about their "aha" moments and the questions they still have about waves. I assess these entries for completeness and coherence of thought.