Happy Valentine's Day--seeing hearts

Here's a really cool video that shows just how much we are pattern seeking animals. We can find hearts anywhere.

You CAN change the world

Never doubt that a small group of thoughtful, committed, citizens can change the world. Indeed, it is the only thing that ever has.

--Margaret Mead

Boy, 7, raises $240,000 for Haitian Relief.

Projectile Motion - 1/19/10

There are multiple concepts that come into consideration when discussing Projectile Motion. Recently, our class (period 1/2) discussed Vertical Velocity (VY), and Horizontal Velocity (VX).

A projectile's horizontal velocity is constant, and has an acceleration of 0. This is due to the fact that there are no substantial forces acting on the object in the horizontal direction. The only horizontal force acting on the object would be air resistance, and in most cases, this force is negligible (i.e. a small steel ball). Because V(sub X) is constant, it's initial velocity is the same as its horizontal velocity at any point in time (unless the object has stopped).

A projectile's vertical velocity has constant acceleration. The earth exerts a gravitational force upon the object that pulls the object towards the earth with a constant acceleration of about 10 meters every second. This is why the object eventually stops moving (in general). The earth's gravitational force brings the object towards it. and the object eventually hits a surface that stops it's motion.

Backyard Ballistics Packet

Here is the reading from backyard ballistics that will tell you how to build a tennis ball morter, catapault, or potato cannon.

Backyard Ballistics

Class on 1/7

today in class we focused a lot on the concept the force of gravity on any two objects will cause them to fall at the same time, despite weight or mass differences.This is because gravity will only exert as much force on and object as it exets on the earth, by having mass orweight. So a light object falling will only exert a small force on the earth, and will only get or require a small reactional gravitational force to make it fall. For a hevy oject, this is true except that it will exert more force on the earth and thus require a greater gravitationl force to be exerted on it. But the objects will fall at the same tie because the gravitatioal forces are different, because the heavier object requires more just to fall at the speed of the light object
Also, we rached the concuion that dropping and object and throwing the same mass object from the same height, without upwards trajectory will result in both object hitting the ground at the same time. Thisis because an objects horizontal motion wil nt affect its vertical motion, so the thrown object will fall at the same time as th oher ball which is dropped, no matter how fast it is going horizontally

Burj Dubai Base Jump

Two basejumpers just set the world record for BASE jumping from the world's tallest building the Burj Khalifa (formerly called the Burj Dubai), from a height of 828 m.

Check out the video below:


Two questions:
1. Why didn't this video take the 13 seconds you calculated take an object to fall to the ground?
2. What was the average velocity of the skydiver? How does this compare to the velocity an object falling only under the influence of gravity would have when it hit the ground?

Wednesday, Jan 6

On Wednesday's Physics class our main or big idea was proving horizontal motion and vertical motion are not related. We concluded that they were not related. We used a cannon on a car to show that when a ball is launched into the air vertically while the car was in motion at a constant velocity horizontally that it will still land in the same place because the ball will still keep its path horizontally after being launched into the air vertically.

the physics of snow

Since it's on all our minds....

Why does snow make everything seem much quieter?

Can it get too cool to snow?


Designer snowflakes from the lab

Physics of snowbaording (don't expect to do much of this tomorrow).

Study Hacks talks about deliberate practice

Another awesome blog post on why just working at something doesn't always make you better. You have to practice in a deliberate way.

What a study of chess experts teaches us about building a remarkable life

Some highlights:

What is deliberate practice?

It’s designed to improve performance. “The essence of deliberate practice is continually stretching an individual just beyond his or her current abilities. That may sound obvious, but most of us don’t do it in the activities we think of as practice.”

It’s repeated a lot. “High repetition is the most important difference between deliberate practice of a task and performing the task for real, when it counts.”

Feedback on results is continuously available. “You may think that your rehearsal of a job interview was flawless, but your opinion isn’t what counts.”

It’s highly demanding mentally. “Deliberate practice is above all an effort of focus and concentration. That is what makes it ‘deliberate,’ as distinct from the mindless playing of scales or hitting of tennis balls that most people engage in.”

It’s hard. “Doing things we know how to do well is enjoyable, and that’s exactly the opposite of what deliberate practice demands.”

It requires (good) goals. “The best performers set goals that are not about the outcome but rather about the process of reaching the outcome.”

Now here's the kicker—since deliberate practice is so hard,

Unless you’re a professional athlete or musician, your peers are likely spending zero hours on DP. Instead, they’re putting in their time, trying to accomplish the tasks handed to them in a competent and efficient fashion. Perhaps if they’re ambitious, they’ll try to come in earlier and leave later in a bid to outwork their peers.

But as with the intermediate-level chess players, this elbow-grease method can only get you so far.

That's right—most students, athletes, aren't doing anything close to deliberate practice.

What do you think will happen when you start doing deliberate practice?

Megawoosh

http://www.youtube.com/watch?v=lkwh4ZaxHIA

This was a 35.2 meter jump. There was tons of planning and physics that went into one jump. It was originally an ad for a Microsoft program called Microsoft office. The rest is on www.megawoosh.com 

The science of Avatar

Here are a few posts that describe the physics of the movie Avatar. In your lifetime, scientists have already discovered hundreds of extrasolar planets orbiting stars throughout the Milky Way (the first extrasolar planet was discovered in 1992).

The science of Avatar

Pandora could be a reality

More science of Avatar

Curious about how we discover extrasolar planets? Here's how.

You can even play a game to discover them on your own.