I occasionally (all the time) tease my students that I will throw them off the roof of the school, or throw things at them from the roof of the school (always to prove a physics point, I swear!).
On their most recent quiz, their answer to a question involving being dropped off the roof of the school needed to involve a diagram.
Apparently my students have mixed feelings about this.
Not only is today Pi Day (3/14) it is also Pi Month! Time to celebrate the inner (and in my case, outer) math nerd. Plus, I love pie.
As March 14 is also Einstein's Birthday, I decided to celebrate by starting a course on Special Relativity with WorldScienceU, the new project of Brian Greene. As I don't have tons of time to devote to it (semester is zipping by, and wedding related things are coming up quick) I am doing the theoretical, not math based course, and opted out of being graded. I've taken both Relativistic and Quantum physics courses in the past, so this is a for-fun refresher!
Neat things are happening in the world of particle physics! Researchers at CERN are pretty much certain they have found the elusive Higgs boson - the so-called "God particle" because it imbues all the other particles we know of with mass.
Interesting article on the University of Alberta connection here. (The guy in the picture, James Pinfold? Taught me Relativistic Physics.)
This could be my favorite Higgs related headline... Thanks CNN.
Our current understanding of physics at the smallest level involves a number of particles that have different properties. However, physicists have been struggling for years to deal with one sticky point... there is no reason why any of these particles should have mass. On their own, there is no reason for the universe to really have mass. The Higgs boson was proposed in the 60's to explain why these particles become massive when they stick together, and named after British physicist Peter Higgs.
(A boson is a type of particle that includes photons and the force carriers, like gluons and gravitons. It all starts to get pretty technical. Don't believe me? Just try reading the wikipedia page on bosons and see how far you get.)
For those of you who are wondering why we care... the same could be said about Röntgen's discovery of x-ray radiation that gave us modern medical x-rays, or the understanding of quantum mechanics that allows our computers to work. It will be a while before practical applications of the knowledge of Higgs boson are realized, but it is no small thing to learn that we have that much more understanding of our universe.
I had a student tell me the other day that he "still doesn't believe that time changes depending on how fast you go".
Because we live in a low-velocity, high-friction world, it is a constant challenge to get teenagers to let go of their misconceptions of how physics works.
Everyone today understands the idea that motion is relative. Galileo first outlined this principle. This is pretty much the idea that if I throw a ball up while I am traveling in a car, it will return to my hand, regardless of the speed of the car. The motion of the car and the motion of the ball are independent. In the car, I see the ball travel straight up and down. Someone on the street will see the ball travel in a curved path, since it is also moving at the same speed as the car. This, in a nutshell, is relativity.
Special relativity (proposed by Einstein in 1905) explains what would happen if the car started traveling really, really fast compared to the guy standing in the street. In 1881, two American scientists, Michelson and Morely, confirmed that light travels at a constant speed. Einstein took this fact to some interesting conclusions. Light always travels at the same speed; so if you gave a flashlight to a guy on a train and a guy standing in the station, both see the light from their flashlight travel at the same speed. Galilean logic tells you that the man on the train should see light go faster, since the speed of the train is being added to the speed of light. But no matter how fast he goes, the light beam will always travel at the same speed away from him.
To keep light at the same speed, distances must shrink and time must slow down for fast moving objects (speed is distance/time).
Lucky for this kid, he doesn't need to believe in time dilation for it to be true. I say "lucky", because if special relativity were not true, his cell phone wouldn't work, and then he'd actually have to do something other than play Plants vs Zombies on a regular occasion.
Last post I mentioned that I was taking my students to West Edmonton Mall to do some real-life amusement park Physics.
We had a great day - the students had a blast (in and out of the park... some of my boys got bra fittings at Victoria's Secret... "Guess what!? I'm a 40-double A!") and it was great to get out of the school and apply the theory from the classroom.
Not such a high point was when I accidentally dropped my phone into a toilet. It survived... but definitely not one of my better moments.
Swing of the Century... Making teenagers sick one field trip at a time.
One of my favorite things about teaching science is watching students realize how neat the world actually is. Teenagers, especially, like to think they know everything, and are prone to acting nonchalant about new information. "Duh. Everyone knows that...." Sometimes accompanied by an eye roll.
But every now and then I can surprise them with something they've never had to think about before. It happens a few times in physics. Good ol' cognitive dissonance. People often think that the math in physics is what's challenging, but it's really not. If you can do algebra, you can do all the math you need to for high school physics. The theory is what's tricky... any one can put a number into a formula and get an answer... but ask them to explain why the water in the bucket over my head doesn't fall out when I swing it?
One of the more challenging concepts for students is the idea of "weight". How much matter is in my body is called my mass, and I measure it in kilograms. We are brought up believing that this is our weight, but it's really not.
Weight is the force exerted on you by the Earth's gravity. When you step on a weigh scale, the scale is calibrated so that it takes the acceleration due to gravity into effect and tells you your mass, not your weight.
Fair enough, you might think. So what's the tricky part?
The tricky part comes when you ask a student why they feel like they have mass. (I once made the mistake of rhetorically asking a group of grade eleven's why I feel heavy, and one of them shouted out "'Cause you're fat!" much to the shock and horror of his classmates. I laughed.) What causes you to feel like you have "weight"? Most people will answer with gravity. But if I ask what they would feel if I threw them off a cliff, they all know that they would feel "weightless".
Feeling like you have mass is a condition of being in contact with a surface, namely the ground. My mass pushes down on the Earth, and in accordance with Newton's Third Law (for every action there is a equal and opposite reaction) the Earth pushes back. In physics this is called the normal force, or your apparent weight. The Earth pushing back on me is what I feel, what gives me the illusion of having weight. The force of gravity is still pulling on me when I fall off a cliff; what is missing is the normal force.
My apparent weight can change under different circumstances as well. Accelerate me up in an elevator and I feel heavier. Start going down and I will momentarily feel lighter as the floor falls out from underneath me and supplies less normal force. It's a mind-baffling concept, because it is quite different from our every day perceptions about the world around us.
Tomorrow, I am taking my Physics 20 class to Galaxyland at West Edmonton Mall to make calculations and observations about different amusement park rides. I'm looking forward to having them challenge their existing beliefs and experience some of these concepts first hand!
The following is the video I used to illustrate how we can artificially create a "zero gravity environment" (really, there is still gravity... just no normal force, because the plane is falling at the same rate you are!). I hope you enjoy it as much as my students did!
So I gave a quiz the other day to my Physics 20 class. Now, typically physics problems are pretty boring ("an object is accelerated at...." or "an object is resting on a...") so I try to spice them up in class.
I stink at drawing (although I've got pretty awesome at stick people) and my kids know it. Whenever we do examples in class that deal with an object, I always ask them, "What kind of object do I have?" and they'll give me "dinosaur", "penguin", or "lumberjack" and then laugh while I try to draw one.
On quizzes, I normally give them an entertaining object to draw, mostly because I like looking at them when I mark them. Some of my students are excellent at drawing, while others are happy enough making all of their objects boxes.
However, the other day I was tired of telling them what to do, so I gave them a fill-in-the-blank quiz. Instead of telling them that a box of armadillos was sitting on a 40° incline, I told them "a ___________ is resting on a 40° incline" and had them decide what the objects were.
I have never giggled so much while marking quizzes. This is definitely becoming a regular occurrence. Teenagers are so funny and creative. I thought I would share some of my favorite doodles.... More to come later!
A wagon full of giraffe...
A 16 kg Santa on a slope
My personal favorite...
a wagon full of 32 kg of "assorted fruits".
Huzzah! I have figured out how to rotate pictures! Go me! Thanks to Kate for the words of wisdom!
So... things are kinda busy around here. I was lined up to take over a particular job at a school, when yesterday an emergency medical leave came up out of the blue.
Being one of the only subs around who actually teaches Physics, they asked me to take it, and I said yes. So today was my first day with three classes of Advanced Placement Science 10 and one class of Physics 20!
Now I am crazy busy trying to plan what these kids are going to do over the next two weeks. Thank goodness for long weekends!
For today, I thought I would share one of my favorite places to get science-related humor (sadly not always classroom appropriate...) - the website LabInitio (home of the comic Nearing Zero). This man is a genius.
By now, most people will have heard about the paper that was published yesterday by scientists at CERN, the European Organization for Nuclear Physics (if you haven't, read this first). Essentially, they obeserved results in their huge underground partice accelerator that are inconsistent with our current understanding of physics. The mass media avaliable to most people who have a basic understanding of science is making this sound like a very big deal... which it could be... but it also could not be.
Papers detailing the results of scientific studies are published to make the rest of the scientific community aware of what the researchers did, and how it worked out. Another reason is to allow peer scrutiny of the results. The CERN researchers are publishing their data, not because they think they can explain it (in the last line of the paper they explicitly state "We deliberately do not attempt any theoretical or phenomenological interpretation of the results.") but because they want other people to attempt to replicate their results before any attempt is made to try to formulate an explanation.
This blog discussion explains very nicely why we shouldn't be jumping up and down just yet...
To be sure, the results are unusual. Einsteinian physics states that nothing can travel faster than the speed of light. The speed limit of the universe is 300 000 kilometers per second, and while objects can get close to this, they aren't ever allowed to actually exceed it. These are exciting times; these results could be explained away using our current model, or a larger theory may need to be developed to explain them.
Is this the face of a man who
would lie to you?
From here.
It is worth noting however, that the headlines that say "Einstein proved wrong!" are grossly overestimating the matter. Einstein revealed the incompleteness of Newton's physics, yet Newtonian physics continues to be a reasonable explanation for how things in our daily lives work. Newtonian physics works very well with objects that are travelling at slow speeds; when looking at objects that are travelling at very high speeds, we need to use relativity. Newton wasn't "proved wrong" so much as he was proved "not totally right"... there was missing information, and the technology avaliable at the time wasn't advanced enough to say otherwise.
We know that Einstein's physics works (thanks to time dilation and the mass-energy equivalence the GPS in your phone works... and so do atomic bombs) but the question is about whether or not it offers a complete picture. It's worth remembering that it has been 106 years since Einstein first published his Theory of Special Relativity. Think about how far much more we know now!
Just like the Michelson-Morely experiments revealed the holes in Newtonian physics, this recent CERN could reveal the incompleteness of Einstein's Relativity. It will take years to do the many trials that need to be done to confirm or deny the results. It is just far too early to say.
This is the heart of science, the mindset that sets it apart from so many other disciplines. Scientists know their knowledge of the universe is incomplete... new evidence that contradicts what we think we know needs to be examined and rigorously tested. If it proves "true" our explanations for the ways of the world need to be modified... not the other way around.
Aside... Reading "science articles" in regular newspapers always makes me giggle. The media's understanding of science is so naive that a study can be published (by very wonderful and smart researchers I'm sure) that suggests a possible link between two factors, and the media will jump all over it with the enthusiasm of Tom Cruise on Oprah's couch. "Guess what!" they will shout, "Scientists just discovered that X causes Y!!" Well, maybe. Suggesting that two things are related and saying that one causes another are two totally different things. One study does not a rule make.
