What Did They Do With It?

So I took a stab at letting my kids have a go at Dan's last installment. And to say I was pleased is the understatement of the year.  The first obvious question was "will it go in the can?" But, since we have finished going over parabolas, kids started asking questions like:

• How high was the ball at its highest point?


• How far did it travel?


• What was its velocity?


• How long was the ball in the air?

The question that really opened one of those "teachable moments" was in regards to velocity.  To this point we have only covered vertical motion.  These kids understand how to model a falling object as well as an object with an initial velocity other than 0.  This led to an interesting discussion.  Does the "falling object" or "thrown object" apply here?  And that is when Lio hit the nail right on the head. 

He pipes up with, "Hey Mr. Cox, if we shoot a gun horizontally and drop a bullet from the same height instantaneously, they both hit the ground at the same time right?"

"Yup."

"So does the fact that it is travelling horizontally have anything to do with how fast it falls?"

"Nope."

"So can we use the stuff we know about falling objects here?"

"Yup."

"But we need heights." 

"Well I guess we are done here."

That is when Seth walks over to the trash can and measures how tall it is.  All these trash cans have to be the same, right?



And the rest is history.  The kids opened up the computers, dragged the images into the SmartNotebook software and here is what Group 1 came up with: 

Here is where it gets really cool.  My other Seth asks if we can find the actual distance the ball travels along the parabola.  He thinks that if we can measure the distance between the balls, then we could get a series of straight lines.  He comes to the conclusion that the closer the balls are to each other, the more accurate our approximation is. 

Wait till he gets a load of Calculus.  Did I mention he is 13?