Freaky Fzx Friday - Stupid Conservation Laws

Your chemistry teacher told you that Matter is Conserved.  She told you that the total mass present before a reaction is the same as the total mass present after the reaction.  Antoine Lavoisier discovered this "law" in 1785 but we've modified that "law" just like most ideas of that vintage.

Your physics teacher will tell you that Energy is Conserved in a closed system.  Discovered in the early 1840s, credit is most commonly attributed to James Prescott Joule and a few others doing similar experiments around the same time.  Yup, that's also a lie.

            

Antoine Lavoisier                       James Prescott Joule

Freaky Fzx Friday - Radically Relative

Einstein based his Special Theory of Relativity on the fact that Light Ain't No Baseball.  He concluded that the speed of Light is the Only Truth in simultaneous events from different perspectives.  Albert also knew that the speed of light (c) is the speed limit of the universe.

Special Relativity is mostly about what are called "inertial reference frames" - dynamic equilibrium near the speed of light (c).  Remember, however, it's all relative  You might observe an electron traveling past you at 90% the speed of light but that electron sees you doing the same speed in the opposite direction and both perspectives are correct.

Anyway, since light is the speed limit of the universe and you don't just hit a speed wall, acceleration according to Newton's Second Law isn't linear.  At least as measured from an external perspective, mass increases with the speed of light acting like an asymptote in this graph:

Relativistic effects noticeable above 10% the speed of light

But remember, you don't notice the mass gain in yourself, you only notice it in somebody else.  Kinda like the pot calling the kettle black or pointing out the speck in your neighbor's eye through the log in your own.

Freaky Fzx Friday - Light is Truth

We know that Light Ain't No Baseball.  No matter how fast you are moving, no matter how fast the object is moving, everybody always measures the speed of light to be exactly the same.

That means that different observers will measure distance and time differently.  

Einstein used trains in 1905 since they were the fastest transportation he had.  Cars were slow, planes could barely fly, and rockets weren't even contemplated for payload transport.  His imaginary trains, however, moved close to the speed of light to conceptually demonstrate special relativity effects - a thought experiment.

Imagine two flashing lights at the front and rear of your train and remember that you are traveling near the speed of light past the stationary train station.  You synchronize those lights while you sit in the middle of the train.  Those synchronized lights are NOT synchronous to the people waiting for the train.

Which perspective is correct?

Freaky Fzx Friday - Light Ain't No Baseball

Imagine that my aging arm is capable of 100 mph just before another dislocation.



You're sitting on your stoop watching me as I travel past you at 50 mph and I throw my amazing fastball toward the front of the bus.  What speed do you measure for the ball?  I see it travel at 100 mph.

Teach Fzx Tuesday - Discovering Torque Failure

I tried something new this year.  Instead of giving the definition of torque and the second condition, they discovered the basic relationship by balancing weights on a meter stick.  It worked.  Kind of.  But the new way sucked in comparison to the way I've done things in years past.  I wanted them to experiment and play with numbers and find the balancing torques relationship but it took way too long and they didn't really understand the relationship when it was done.

I prefer the activity where they used the same balancing meter stick and summed the torques about several points just to prove that the net torque about any point is zero - the second condition for equilibrium.  That's a good one.

Better to try something new and fail than never to try at all.  That's how I learn.  I fail often.

Freaky Fzx Friday - Electrons are WAVES

Do you think electrons shed tiny quantum tears when they realize that we don't understand them?

I mean, seriously, 120 years after their discovery and over a century after scientists observed the wave nature of electrons, the average person has no idea that the electron is nothing like a planet.  The problem is exacerbated by important organizations and popular television programs promulgating the lie.  If I were an electron, I would be sad.

                   

US Nuclear Regulatory Commission                            Big Bang Theory on TV

Teach Fzx Tuesday - Dynamic Equilibrium

Following a test on static equilibrium we move on to what I like to call "dynamic equilibrium."  There is no real difference between them but my students think there is.

As an introduction, they sketch the side view of their favorite vehicle on a straight, flat road moving to the right at a constant velocity of 78 mph (or whatever speed they give me).

Then I ask them to sketch a Free Body Diagram of the vehicle.  We talk about what to name the forces but I am careful to emphasize only that the vehicle is moving at a constant speed on a level, straight road.