Week of 5/12 - 5/16

This week was a bit short because I had the AP Lang test on Wednesday, but it was still very productive, and I got a lot done. I started this week by printing out the leg extensions and attaching them with hot glue to the electromagnet base. They seem to be very stable so far and are a lot better than the PVC pipe cover I had been using previously.

Next, I wanted to test the air resistance that the magnet would be receiving while spinning. I decided that testing the rpm and how fast it declines would give me a good reading as to how fast it would slow down if I used a motor to spin it. I used a laser tachometer to measure this, and to get it to register, I had to apply a piece of reflective tape to the magnet so that the tachometer could read it. The sticker is not very thick, so it should be fine, however, I believe that on a real test without the sticker, it will spin for a little bit longer since the sticker still has a small amount of air resistance

I set up the tachometer so it was at the optimal height, where the magnet was perfectly in its range, then started spinning the magnet. I spun the magnet by hand since I didn't want to wait too long for it to slow down in rpm. I then started a timer and measured the rpm as well as the time periodically. I tried to get at least 5 points so that I could make a good equation. I started spinning it at 400 rpm and throughout 40 minutes, slowed down until about 40 rpm.

I wrote down the times on a notepad and included the time in seconds. Then, I made a table in Desmos and used it to find the curve of best fit. The R^2 value was pretty close to 1 at 0.9964, so the equation is pretty accurate. I predicted that the magnet would stop around 1 hour, which seems pretty reasonable considering that the slower the motor went, the slower it slowed down. I will continue to collect data next week, and I will also try to get data on higher rpms.

If spinning the magnet just by hand already lasts for an hour, then spinning it with a motor will surely make it last longer. I looked up the longest a hand-spun top spun for without a vacuum, and it was a little over an hour. This is primarily due to the design of the top, and I suspect that if I redesigned the magnet to make it better at spinning or added a machined part around it that it will spin for much longer.