A long while ago, I taught a summer camp class called "How to Walk Through Walls." It was a physics class that culminated in the idea that matter is really made of waves of probability, and these waves could in principle transport through barriers — that is, you could in theory walk, metaphorically speaking, through a wall.
Well, you can't, but a team in Finland has proposed observing the effect, called quantum tunneling, in a mechanical system. That's something no one's done before, and if they succeed, it will be really, really cool.
Read the story here.
Tuesday, November 29, 2011
Monday, November 21, 2011
200 Words or Less: Newton's Third Law
Don’t worry too much when that schoolyard bully shoves you — according to Newton’s third law, you’ve already shoved back.
The law — for every reaction there is an equal and opposite reaction — really means that when one thing pushes on another, the second one pushes back just as hard in exactly the opposite direction.
It's easy to see what the third law is all about. Grab a friend and head to a skating rink. Once on the ice, stand next to your friend and gently push. She’ll go in the direction you pushed her, but you’ll go in the opposite direction. That's because when you pushed your friend, she pushed on you, too.
Now think about this: when you jump up in the air, you push on the ground, just like you pushed your friend. That means two things: it's the earth pushing on you that tosses you in the air, and you're pushing on the earth, making it move, if only a little bit.
Now, if the earth isn't immovable, can it be the center of the universe? The third law says "no," and along with other insights, it began to permanently undermine the idea of an earth-centered universe.
Bonus experiment! It doesn't fit in 200 words or less, but you can also feel Newton's third law. Grab your friend again, get a basketball, and pass it between you. Pay attention to what you feel on your hands — pressure. That's the force of the ball pushing on you when you pass it.
The law — for every reaction there is an equal and opposite reaction — really means that when one thing pushes on another, the second one pushes back just as hard in exactly the opposite direction.
It's easy to see what the third law is all about. Grab a friend and head to a skating rink. Once on the ice, stand next to your friend and gently push. She’ll go in the direction you pushed her, but you’ll go in the opposite direction. That's because when you pushed your friend, she pushed on you, too.
Now think about this: when you jump up in the air, you push on the ground, just like you pushed your friend. That means two things: it's the earth pushing on you that tosses you in the air, and you're pushing on the earth, making it move, if only a little bit.
Now, if the earth isn't immovable, can it be the center of the universe? The third law says "no," and along with other insights, it began to permanently undermine the idea of an earth-centered universe.
Bonus experiment! It doesn't fit in 200 words or less, but you can also feel Newton's third law. Grab your friend again, get a basketball, and pass it between you. Pay attention to what you feel on your hands — pressure. That's the force of the ball pushing on you when you pass it.
Monday, November 7, 2011
Newton's First Law — in 200 Words or Less
Reading my recent post about gravity the other day, it occurred to me that it might be fun to go back and do some basic science— in 200 words or less. Part exercise for me, part shot of science espresso for you. Today, Newton's first law.
It’s a humble but profound statement: objects in a state of uniform motion tend to remain in that state unless an external force acts on them. In plain English, Newton’s first law means that if you throw a baseball, it will go in a straight line at constant speed forever unless something pushes or pulls on it.
Of course, wind resistance and gravity are always pushing and pulling, so baseballs never go in straight lines at constant speed. To see the first law in action, find an ice rink or an air hockey table, and toss a puck along it. It’ll go straight at fairly constant speed for a while — longer, anyway, than a baseball would.
Why is the first law important? People once thought objects tended to stay motionless, so you had to push to keep them moving. They missed what’s obvious today: it’s friction that slows things down. Without friction, gravity, and other forces, things like hockey pucks and baseballs would keep moving forever.
Newton’s first law challenges us to think of all the forces involved, like friction and gravity. By doing that, it opens the door to a deeper, farther-reaching understanding of the physical world.
It’s a humble but profound statement: objects in a state of uniform motion tend to remain in that state unless an external force acts on them. In plain English, Newton’s first law means that if you throw a baseball, it will go in a straight line at constant speed forever unless something pushes or pulls on it.
Of course, wind resistance and gravity are always pushing and pulling, so baseballs never go in straight lines at constant speed. To see the first law in action, find an ice rink or an air hockey table, and toss a puck along it. It’ll go straight at fairly constant speed for a while — longer, anyway, than a baseball would.
Why is the first law important? People once thought objects tended to stay motionless, so you had to push to keep them moving. They missed what’s obvious today: it’s friction that slows things down. Without friction, gravity, and other forces, things like hockey pucks and baseballs would keep moving forever.
Newton’s first law challenges us to think of all the forces involved, like friction and gravity. By doing that, it opens the door to a deeper, farther-reaching understanding of the physical world.
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