A. Mindful moment. https://www.youtube.com/watch?v=9mopikvt114
B. Review previous DSN entry.
C. Preview blogpost for the day.
D. Create new DSN entry for the day. (Motion folder)
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“As a boy, I was fascinated by speed, by the wild range of speeds in the world around me. People moved at different speeds; animals so much more so. The wings of insects moved too fast to see, though one could just their frequency by the tone they emitted–a hateful noise, a high E, with mosquitoes, or a lovely bass hum with the bumblebees that flew around the hollyhocks each summer. Our pet tortoise, which could take an entire day to cross the lawn, seemed to live in a different time frame altogether. But what then of the movement of plants? I would come down to the garden in the morning and find the hollyhock a little higher, the roses more entwined around their trellis, but, however patient I was, I never could catch them moving.”
Oliver Sacks in “Speed,” an essay from The River of Consciousness (2017). Picador.
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Finish investigation of pullback car from previous class.
A. Make a new group of 3. These should be students you have not worked with before (or have worked with the fewest number of times). Update your collaboration chart / document. Names, topics, activities, dates, links (relevant blogposts, DSN entries, group documents and data)
You will receive a pullback car. Explore its operation. Do not overstretch the spring, but do find the point that gives maximum acceleration and distance. Do a trial run without measuring. Each student separately make a sketch graph (distance vs. time) of how you think the motion would look. Discuss with your group your ideas using your sketch graph to illustrate your point. Make sure you have a rich entry for the section “what we talked about” in your DSN entry.
Design a track (frame of reference) to evaluate how the speed changes. This will be very similar to your tumble buggy procedure. Find the times to reach various distances. Make a distance vs. time graph to display your results. Calculate the average speed for zero meters to the maximum distance you measure. Can you find average speeds for other segments, like from 0-1, 1-2, and 2-3 meters?
Compare a graph that shows average speeds from 0-1, 0-2, and 0-3 meters with a graph that shows average speeds for 0-1, 1-2, and 2-3 meters.
What happens to the graph if average speeds are found for smaller and smaller segments of distance and time?
Be prepared to share your findings with the rest of the class.
***All students: Reply to today’s blogpost. Describe how you think the pullback car works. What do you think makes the car change its speed from 0 m/s to the other speeds you observe during a trip? What is the mechanism do you think? Make a sketch of your imagined mechanism and add link to blog–with sharing so that anyone with the link can view. Be sure the response that you submit on the blog is also copied into your DSN entry for the day.
Reply to another student’s comment. Ask a clarifying question about their sketch and the mechanism they have proposed.
B. Thought problem. Answer with a sketch graph (distance vs. time) and description. If a cart is pulled with a constant force, what motion do you think will result?
C. We shall watch and discuss in detail the motion examples presented in: Frames of Reference < https://www.youtube.com/watch?v=bJMYoj4hHqU >. What is your understanding of the statement, “All motion is relative?” If we do not have time to watch this as a class, watch on your own. Have your questions ready. Be prepared for a quiz in an upcoming class.
This is good. Take a look: https://www.arborsci.com/cool/newtons-laws-revisited/?utm_source=Coolstuff+Newsletter&utm_campaign=e6f82091c1-Newton%27s+Laws+Revisited&utm_medium=email&utm_term=0_c5b08a4766-e6f82091c1-229626089&mc_cid=e6f82091c1&mc_eid=08e9d4773a