Methods 2: Week 4

 

Week 4 

1. The big question addressed in lab, and a description of what you did.

 We started Lab this week by breaking down the slide activity from last week. Some of the big takeaways were that rider weight doesn’t matter because acceleration and the force of gravity cancel out. A heavier rider has more gravity acting on them, but they take longer to accelerate. A lighter rider is the opposite. Also, height is important because more height means that a rider has more time to accelerate. This week, we had to work in our groups to come up with an investigation about swings. Our group chose to explore how weight impacts the time it takes a rider to swing back and forth. I would have expected a heavier weight to swing back and forth faster initially, but after the slide investigation, I thought that the results would be pretty similar. In order to carry out the investigation, we used a stick, a clamp, a string, a clamp, three washers of different weights, and a timer. We began by tying a string to the stick and then clamping it to the table. Then we tied a washer to the end of the string (starting with the lightest). To perform the experiment, we pulled the washer back like it was going up on a swing, let it go, and then timed how long it took the washer to swing back and forth 10 times. Then, after we got the time, we found the average time it took to complete a single swing to record. We repeated the experiment three times per washer weight. As a result, we found that there was no significant change between the average times it took any of the washers to swing back and forth. Therefore, weight does not play a big role is swing speed. Just like the slide, acceleration and gravity are balanced out between the different washer weights. 

1. A description of what you learned in Thursday's lecture.

In lecture, we broke down the swing experiment from the lab. We started by discussing the forces that affect a swing’s period. These forces include gravity, air drag, and the force from the rope. Then we broke down some of the results that we found from the experiments that we conducted. A lot of groups chose to investigate weight, and their results were the same as those of my group; we all found that weight does not impact the period of a swing. This is because gravity and acceleration balance out. Just like on the slide. Then we discussed Newton’s first and second laws. In terms of describing why weight doesn’t matter, we focused on the second law (F=MA)— larger masses are harder to accelrate. Finally, we ended the lab by focusing on the swing from an energy perspective by watching a pendulum. When the pedulum was at its peak, potential energy was at its peak because it had the most potential to begin moving and doing something from that location. When the pendulum was at the bottom (moving the fastest), kinetic energy was at its peak. We also noticed how the total amount of energy never changed; just the amount of kinetic and potential energy changed. As we had more of one type of energy, the other decreased. 

1. Answer questions about the weekly textbook reading:
1. What did you learn?

The chapter focused on talking about pendulums, which are basically something that swings back and forth, like a swing. The time that a pedulum takes to swing back and forth is called a period. The chapter discusses that weight doesn’t impact how fast a pendulum swings because of its potential and kinetic energy. Potential energy is the energy something has when it is still but could move. Kenetic energy is the energy of something while it is actually moving. As a pendulum swings, the energy changes (between kinetic and potential). This is why a pendulum keeps swinging; until other forces like friction slow it down. Additionally, the chapter discussed how the length of a string or chain impacts the speed of a pendulum. Longer strings make the pendlunm go slower (longer length to cover), while shorter strings go faster. 

1. What was most helpful?

I thought that the real-world examples and visual aids were helpful in helping me understand the content. I liked the 2D animation and video demonstrataions, specifcially the pedulum waves, did a good job explaining how energy changes while a pendulium moves. 

1. What do you need more information on?

There isn’t anything specific that I need more information on at the moment. Between the book, lab, and lecture, I think that I have gotten a comprehensive explanation and have developed a very good understanding of the topic.  

1. What questions/concerns/comments do you have?

Thinking back to the swing expiration I wonder how energy or speed is impacted when a rider jumps off of a swing. From my experience, I know that a swing tends to lose its momentum and come to a stop soon after this happens. Why?