# APlusPhysics Blogs

Showing blog entries posted in for the last 365 days.

1. Earlier
2. ## Public Service Broadcasting "The Race For Space" Essay

Lmao, I'm happy with this story.
3. ## Eternal Recurrence

Kind of like a donut -- it's hard to tell the beginning and end. Well, unless you eat it, and the first bite is the beginning, and the crumbs are the sad end.
4. ## School Has Ruined Me

I really think you need a bowl of ice cream. With rainbow sprinkles. Perspective, HegelBot, perspective...

6. ## KSP for Dummies - Lesson 1: The Interface

I think this tutorial nets your team a bonus \$7.5K.
7. ## Siphoning Fluids

If you haven't read my last 2 blog posts, you should. They both directly relate to what I'm talking about in this one. Alternatively, if you have even the slightest understanding of fluid dynamics, you don't need to read my last 2 posts. In reality, if you've never even thought about fluids, you don't need to read my last 2 posts, because this is actually pretty simple, especially when compared to what we've done in class this year. Right now, our goal is to get fluid from one cup into another. We could just pick up one cup and pour it into the other, but that's boring, and not very easy to do with large amounts of liquid. We could just scoop it out of one cup and dump it into another over and over, but that's boring and time-consuming. We could just pray to the old gods, but that also comes with its own drawbacks. So what are we going to do? We're going to siphon it through a tube. Now take a look at the following gif. The fluid from the left cup is transferring into the right cup, until they equalize to one height. If we wanted to transfer all of the liquid, we could just put the right cup at a lower level. The issue with siphoning like this is that we can't just drop one end of a tube in each cup and expect it to work. If the tubes were connected from the bottoms, this wouldn't be an issue. In this case, the transfer had to be jump-started, so the fluid travels up-hill into the tube, before it falls back down, and begins dragging more fluid with it. One way to jump-start the transfer is to submerge one end of the tube into the left cup, then suck on the right end a little bit so the fluid starts to flow into the tube, and passes the highest point in the tube. Then, stop sucking, and put the end of the tube into the other cup, and as the fluid falls, it will drag more with it. Another way is a little more tricky, but also more clean. It starts the same, with one end of the tube submerged in the left cup. Then, bend the tube so that it goes down out of the left cup, then back uphill, like a "u". Then, pour a decent amount of liquid into the "u". After, while making sure the part of the tube in the left cup stays submerged, put the other end of the tube facing down into the right cup, so the liquid starts pouring out. When the liquid starts pouring out, it'll drag more behind it, and eventually out of the left cup.
8. ## Under Pressure

The system above shows a cylinder with a small diameter (Gutter) connected to a cylinder with a larger diameter (Barrel). The force due to gravity by the liquid in the small cylinder is less than the force due to gravity by the liquid in the larger cylinder, since there's much more liquid in the larger cylinder. Shouldn't this make the liquid in the small cylinder rise, until the forces equal each other out? In reality, no. The fluids in a system always like being at the same height. This made absolutely no sense to me until I decided to look it up, and found out that it actually isn't that complicated, and I should feel ashamed. The reason that the fluids are at the same height isn't because they apply the same force, it's because they apply the same pressure. And since pressure is equal to force divided by area, it makes sense that in order to have a small amount of liquid be at the same height in a system with a larger amount of liquid, it would need to be put in a container with a smaller cross-sectional area. Alternatively, it could be put at a different elevation, but that's just cheating.
9. ## That Good Ol' Straw Trick

Everybody on the planet probably knows this simple trick. All you do is take a straw, submerge part of it inside of a liquid, cover the top hole of it with your finger, then take it out, and voila! The liquid stays inside of the straw rather than draining out, as gravity intended. But how does it work? It's actually pretty simple, but most people don't really think about it. If you just stop reading for a minute and really just think, you'll figure it out. I didn't just make this post to tell you to think. This is for a grade, so I need to put at least some effort into it. It's all a matter of pressure. By plugging the top of the straw, you isolate the air on the inside from the atmosphere. If the liquid were to start draining from the straw, that would increase the volume that the air would have to take up, without increasing the amount of air in the straw. If you were to turn it upside-down, the liquid won't move, it'll stay hovering in the straw, because if it were to start falling down, that would decrease the volume that the air would have to take up, without decreasing the amount of air in the straw.
10. ## Video games are kinda physicsy

Oh like chunks? I remember the days I was really into stuff like this, age kills curiosity though. Also too many blows to the head probably makes lesions on the "curiosity cortex".
11. ## Happy Birthday!

Happy birthday to Mr. Gauss!!!
12. ## Physics of Mario Kart

I don't know if I would go as far to say the greatest game of all time, but still pretty good! Nice to tie some physics into a classic series!
13. ## Aurora Borealis

Many of us know the Aurora Borealis as the 'Northern Lights'. This natural phenomenon is, of course, thanks to the physics of our Earth and its atmosphere! (Photo credit: NASA) The Aurora Borealis is an extremely beautiful event that occurs most often close to the magnetic poles of Earth. It occurs due to charged particles coming from the Sun of which collide with other molecules found in the Earth's atmosphere. Solar winds from the Sun carry these charged particles and when the wind passes by Earth, particles may be trapped in the atmosphere from the Earth's magnetic fields! The charged particles ionize molecules in the atmosphere, which give off light. This creates the Aurora Borealis! I had previously thought that the Northern Lights were from light reflecting somehow, but it awesome to see that it is caused by magnetism, which fits into our past few units very nicely.

Want to keep up to date with all our latest news and information?