Momentum and an asteroid hitting the Earth

This past week we started to study momentum, and how to give an object momentum by exerting a force over a period of time, or an impulse.

One demonstration the students enjoyed was throwing eggs at a sheet.  Here we can see the students throwing an egg at a sheet, yet it is not breaking!  The sheet extends the time of impact, thus lessening the force.  Here you can see this is slow motion thanks to Stav and his iPhone.  10 points for Hufflepuff.


In the coming week, we will be examining collisions.  In time for Halloween, I call this lab “Creepy Crawly Carts that go BUMP in the middle of the night.”   Some carts go BUMP and stick together with Velcro.  Some carts are silent and make no noise when they collide (magnets).  Other Creepy Crawly Carts go BOOM in the middle of the night.  They ‘explode’ apart using a spring loaded plunger.  Click here to view the lesson on these Creepy Crawly Carts.

Often students (in a panic) ask m if it is okay that they have not done their homework.   I sometimes facetiously answer that the only thing that will prevent the asteroid from hitting the Earth is a completed homework assignment.  Well, the asteroids have been in the news a lot recently.

To quote Craig Robinson, director of the Copernican Observatory and Planetarium at CCSU, “Speaking of asteroids hitting the Earth one of the largest, if not the largest found so far, fragment of the meteorite that landed in Russia this past February has been found in the lake next to the city it landed in. This particular fragment looked to be about the size of a desk and is roughly roundish in shape. They tried to weigh it but the scales they tried to weigh it on broke so at the time I saw the news cast about it (This morning.) there was no idea about its weight other than it was very heavy for its size.”

Here is the CNN video on finding the piece at the bottom of the lake.


There was also a recent deluxe article on the asteroid on BU Today.  Just how are we going to save the Earth from the asteroid, which has a LOT of momentum?  Can we blow it up?  Or do we nudge it slightly?  Deliver an impulse with a laser beam?   If we exert a small force (laser) over a long period of time, we can still deliver a significant impulse to the asteroid.  Read what BU Professor West Jeffrey Hughes has to say on the subject.  I think if we take all the uncompleted homework assignments from BUA students over the years, put them in a rocket, and launch it at the asteroid it might provide just enough impulse to push the asteroid off course and save the world!  I should enter this idea into the NASA Grand Challenge.