rallain | June 24, 2010I was having a discussion with my father about the budgetpocalypse for universities. I don't know how it came up, but he asked: "What college is the department of Math in?" At Southeastern Louisiana University, the Department of Math is in the College of Science and Technology.
Here is a paraphrase of our conversation.
Me: That is odd. Math isn't a science, and it isn't really a technology. Well, I guess you could argue it is a technology.
Father: What? Math is a science. It is a pure science.
Me: I don't think it is a science. Science is all about models and seeing how they agree with…
rallain | June 24, 2010The Louisiana Board of Regents is promoting a 'performance-based' funding model for the universities in the Louisiana system. In short, the funding each university will receive is based on:
The percent of students that graduate
Graduating more non-traditional students and minorities
Accepting and graduating more students that transfer from community colleges
Here is my main problem with this funding formula. Don't we want to do these things anyway? Isn't this suggesting that we are not trying to do these things and if we do try, we will get more funding. Actually, it is not about trying…
rallain | June 21, 2010Of course I am talking about Arnold Schwarzenegger. After looking at how many bullets he carries in Commando, I remembered this scene (also from Commando) (warning: maybe some not great language and some killing. You have been warned)
If you don't want to watch that clip, here is a shot (sorry for the quality).
Clearly Arnold is strong, but there is more than strength involved here. Oh, don't bring your "he did it with wire stuff". I am not buying that. Also, I am talking about THE Arnold - he is real. I am not talking about the character in the movie (not real). Now for some physics…
rallain | June 16, 2010Somewhere on the internet, I came across this Cracked.com article on movie myths about guns. The article wasn't too bad, but I really liked this video they included from Arnold's movie Commando.
The myth for this particular clip was that guns never run out of ammo in the movies. Right away, I thought: I wonder how many bullets he shot? BRING IT ON.
First, I am going to find the fire rate of Arnold's weapon. Oh, I know I could look it up on Wikipedia or something - but I am not going to do that. I am going to determine the fire rate from the clip.
After capturing an audio segment where…
rallain | June 15, 2010Pre Reqs: electric potential, electric field, work-energy
To start, remember that for a constant electric field the change in electric potential energy would be:
WARNING: that is only for a constant electric field. I know you will be tempted later to use this for a different electric field, but DON'T DO IT. But if not that, then how do find the change in electric potential for a point charge? Let me start with a conceptual question. Suppose there were two point charges, both positive but one is held in place. If I hold the other point charge a distance r away from the other charge and…
rallain | June 14, 2010Suppose there was an imaginary university. (is that statement redundant?) Let me call this TIU (The Imaginary University). Also, suppose TIU offers summer courses. Further, suppose there is an instructor teaching 2 sections of lab during the summer. Here is a communication that instructor might have received.
Dear Person Teaching a Summer Course:
It appears you are teaching 2 sections of lab. One lab only has 13 students enrolled in it. We have determined that it is not financially appropriate for us to give you a full course pay for this partially full lab. We are going to pay you 13/…
rallain | June 14, 2010Pre Reqs: Electric Field, Work-Energy, Potential Energy
If you are already familiar with the topics listed in the pre-reqs above, this will be uber-simple.
Potential energy - short version
The work-energy principle basically says:
In this most basic form, the energy is just kinetic energy (if you are not going near the speed of light). BUT...if you have a force that is conservative (meaning the work done does not depend on the path you take), then you can make it a potential energy and move it to the other side.
Warning: you can not have a force and have that force do both work AND be a…
rallain | June 11, 2010Back to the discussion about hiding an electric motor in a pro racing cycle. Before, I looked at a video of Fabian Cancellara to see how his speed and acceleration compare to other bikers. The claim on the internet is that he pulls away so fast that he must have a motor hidden in his bike.
Just to be completely clear, I don't think he is cheating. Then why bother? If you ask that then this must be the first time you reading this blog. I welcome you. No, but really, this is what scientists do. How hard would it be to cheat?
From my analysis, it seems that a person could ride like he…
rallain | June 10, 2010In the last episode of MythBusters, they wanted to see if a tornado could make some glass cut off a person's head. The first attempt was just to take some glass and through it at a simulated human neck. Clearly, this wasn't quite the same as a tornado.
So, here was their plan. If they want to simulate glass moving at 300 mph, they could get a bigger piece of glass and put it on a truck moving at 80 mph. The result would give a piece of glass with the same kinetic energy as a smaller piece moving at 300 mph. Their calculations look to be correct. However, the question is: would this make…
rallain | June 9, 2010Here is another question from Ask a ScienceBlogger. Reader Uday Panta asks:
How does water evaporate in the seas? Doesn't water evaporate at 100 C?
There were some very good responses in the comments where the question was, but I am going to answer it with some more details.
Small Particle Model
This is where we need to start - the small particle model of liquids and gases. This model treats the liquid as being made up of a lot of particles (well, obviously). If there is a gas (or liquid) at a certain temperature, then there are particles moving around at different speeds. Often it is…
rallain | June 8, 2010Well, maybe that isn't the best title. You see, there is this video going around saying that it is possible that a professional bike racer was cheating by putting a hidden motor in his bike. I am not really going to talk about the cheating aspect (my gut feeling says that it would be too easy to catch, so he is not cheating).
Actually, there was an interesting analysis by Ron at CozyBeeHive. Quite a thorough job. He even used Tracker Video Analysis. However, he didn't use some of the nicer features of Tracker, so I figured I would do this analysis also. Plus, you know I love bikes.…
rallain | June 7, 2010As part of the Ask a ScienceBlogger series, reader Jim Swanson asks:
When I open the dishwasher after washing and the contents are still hot, why do the glass and ceramic items dry off more quickly than the plastic items?
This is a great question. Great because it is something most everyone can relate to and great because there is some good science. Really, this shows the difference between temperature and thermal energy. I think the common idea is that temperature is a measure of the energy something has - but this isn't quite true.
Ok, let me first start with a sample case. Suppose you…
rallain | June 6, 2010So, I hear you are starting your second semester of physics. One of the cool things about physics is that the second semester still uses stuff from the first semester. Maybe you forgot some of that stuff, so here are the bare essentials you will need to get by (this is assuming you are in the algebra-based second semester of physics)
Vectors
Really, just about the entire semester course is about the electric and magnetic field. Both of these are easiest to represent as vectors. So, you pretty much need to know how to deal with vectors. Here are some reviews:
How do you represent vectors…
rallain | June 4, 2010I got tired of attacking ESPN Sport Science. Well, tired of attacking might not be the best term. How about, attack in a new way (here are my older Sport Science attacks).
Check out episode 1 of Spoof Science:
A couple of notes:
Watch it youtube if you want the HD version
Making videos takes WAY longer than a blog post
If you hate hearing your own voice, you will really hate hearing your own voice AND seeing yourself while you are editing
rallain | June 4, 2010Honestly, I was going to add this to my previous post about the jumping car but I didn't because I wanted to finish. So, here it is and more. Actually, I will just make a projectile motion spreadsheet. That way, anytime you want to do a projectile motion problem, you can come here. Maybe this is a bad idea, but I am going to do it anyway.
To start with, I will just say that for projectile motion the horizontal and vertical motions are independent (except for the time it takes). If you want a refresher on projectile motion, here you go. Oh, a couple of assumptions:
Object starts at x =…
rallain | June 3, 2010Reader Colin asked a great question about this popular clip.
How fast was the car moving?
First, a quick assumption. I will assume that the frame rate on the video is correct (meaning not slowed down). Colin already looked up the length of the Chevy Impala on Wikipedia for me. It has a length of 5.09 meters (I need that to scale the video).
This is the data I get from Tracker Video. The graph below is the x-position of the car with a line fit to the part of the motion before it hit the "ramp". Note that since the car is moving to the left, it has a negative x-velocity.
So, this says the…
rallain | June 2, 2010This idea comes up every once in a while. The idea that an institution should remove its physics degree program because it doesn't produce enough majors. Right now, it is up again due to budget problems in our state.
I think the idea of removing low-completer programs is dangerous. It comes from administrators who like to think of the university as a business. If you are a business, and you want to save money - it seems obvious to cut things that don't produce as much 'product'. Really, this brings up several issues.
Is a university like a business?
I am going to go with "no". Let me…
rallain | June 1, 2010Sue from Math Mama Writes... sent me an email about wrapping a rope around a pole. In that post, Sue thinks about rope looped around a post. When you wrap a rope around a post, the friction between the rope and the post can help you hold something (like a horse) that is much stronger than you.
The first case she thinks about is using several posts. What if you wrap a rope around one post and pull? What if you use 2, or three posts? The idea is that if one posts 'multiplies' the force by 10, two posts would have an effect of multiplying by 100 and so forth. That seems reasonable.
The…
rallain | May 31, 2010We went to the aquarium, the kids like it. In the Amazon river section, they have an electric eel. Here is the sign next to the Eel.
Sorry for the poor image quality. I took the picture with my crappy phone and didn't even realize it was bad until later. I used some magic on it to make parts of it readable, but if that was not good enough, here is what it says:
The Electric Eel is the most powerful of all the electric fishes. It can discharge up to 650 volts: six times the power of a household current. A shock can fend off attackers or stun prey so the eel doesn't risk getting hurt in…
rallain | May 31, 2010So suppose you saw something that looked like this:
This is a ball shot out of a shooter device. Well, it is a vypthon animation of a ball. What would you do if you came to see this video? If I had not made it, I would say it is an unrealistic video. It does not agree with my basic model of how things move after being thrown or shot or whatever. Interestingly (but unrelated) there was a set of physics questions that showed different possible paths of a thrown ball. The path representing the motion above was a common choice.
Like I said, I made that animation. Here is another one. In…