Rotation in Tennis

My week was pretty mundane, however, I did practice tennis and remember some movements involving physics. This week, I worked on hitting the ball out of the air. This is hard to do because you need to rotate your body to generate speed and get the ball to go over the net. I realized that rotating your body makes it easier to hit the ball hard rather than just slapping at the ball because you produce angular momentum as you are rotating towards the ball. If you just try to hit the ball by using you arm, your arm and your shoulder will get sore because you aren’t following the laws of physics by using torque. I think rotational forces are stronger than linear ones, which is why you should rotate your body but also lean forward as you hit the ball because you need both angular and linear momentum to get the ball to go forward and hit the ball hard. This is a pretty simple concept in tennis, but it requires hard work to rotate and hit through the ball every single time. That’s why you have to go back to the basics and think about the rules of physics.

Malasadas

Okay, I had a pretty tiring weekend so far. I mainly just played tennis and hung out at the fair. What I remember most from last night was making malasadas, so I'm going to try to explain the physics involved in making malasadas. First, to make sure your hands don't stick to the dough, you need to put oil on them. Next, when you get the dough, you have to massage it and spread it out to get the bubbles out. Then, to actually make the malasadas, you need to grab some dough, make a ring shape with your fingers on one hand, and use the other hand to push the dough up through your fingers. You need to make sure the dough is smooth on top so that the malasadas cook properly. Finally when the malasada ball looks smooth and round, you pinch off the bottom to get it to the size that you need it to be. I think by learning the physical aspects of making malasadas, I was able to make the malasadas more effectively and more tasty.

Hot Tub Jets

I went to a pool party yesterday and sitting in the hot tub made me wonder how a hot tub actually works. So, I looked it up on the internet. It turns out that there is a lot of physics involved in the functioning of a hot tub. I learned that a hot tub works by pulling water through a system of pipes and through a heating device before ejecting the water into the tub. Some kind of suction or pressure filtration system draws the water from the hot tub and into a filter. The water is checked for impurities, goes through a pump, and finally, the water gets filtered. After getting filtered, the next step in the process is heating the water. The water is heated to a certain temperature, and there are flow switches and an overheating switch that are used to control the temperature and flow of the water. The water then passes through pipes before reaching the jets. Today, the jets of hot tubs use air induction, which allows warm water to mix with air, to make the stream of water from the jets extra strong. Now I know the sort of physics that goes on in producing the stream of water from hot tub jets.

Wave Interference Patterns

When I was taking a bath the other day, I squeezed the water out of my hair in the bathtub and noticed interference patterns forming from the droplets of water. There were regions of dark and bright interference. I realized that I could create my own constructive and destructive interference patterns. Today, I decided to try creating them again in my sink. In the picture, you can see waves of constructive and destructive interference. They remind me of waves in the ocean. The higher points (crests) are constructive interference and the lower points (troughs) are destructive interference. The shape of the medium can be determined by the sum of the amplitude of interfering waves. Constructive interference occurs when a crest meets a crest, creating yet a bigger crest. Destructive interference occurs when a crest meets a trough or vice versa, creating very small peaks. From doing this little experiment, I learned first hand how waves are created and what constructive and destructive interference look like.