Teaching Newton’s Laws Easily


Misstamiile-aneous Scientific Principles | Teaching Newton’s Laws Easily

by: Tami O’Connor

One of the things I enjoy most about my job at Educational Innovations is conducting teacher workshops.  It’s not quite the same as being in the classroom in front of twenty-plus students, but it’s fun nonetheless.  My favorite presentation is titled, 3-2-1 Blastoff!  In it, we deal with energy, forces, and motion.  I use the Mighty Missile Launcher to demonstrate these topics.

It is exactly that…  a missile launcher.  The good news is this missile launcher can be used safely in a classroom with children from kindergarten to High School. Participants need safety glasses or goggles.

The launcher is primarily constructed of a film canister, a straw, and a balloon. The balloon has a sponge-like material inside that functions to re-inflate the balloon quickly.  The balloon is attached to the film canister so little air is able to escape.  The film canister pivots, allowing you to aim it at differing angles.  The four missiles are simply straws, sealed on one end, with foam fins that stabilize them as they fly through the air.teaching newtown's laws

I first demonstrate how the missile is launched.  The missile is loaded onto the launcher by sliding it onto the straw that is slightly less narrow than the missile.  Since the balloon is connected to the film canister, air can flow easily between the two.  Depressing the balloon forces air into the film canister and out through the attached straw.  When a missile is loaded onto the straw, the forced air propels it into the air.  The harder and more quickly the balloon is squeezed, the faster the air flows into the missile.Newton's Laws 1

Next, I make groups of three or four individuals, and I challenge my teachers to consistently land three out of four missiles inside a target area 1 meter away.  Seems like a cinch, right?  Not so fast…  As with every good science activity, there are several variables that must be controlled.  The first is the force at which the missile is launched.  The harder and faster the balloon is squeezed, the faster the air is compressed and the farther the missile travels.  The second is the angle at which the film canister points.  The greater the angle, the higher and shorter (in horizontal distance) the missile travels.

 

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The Revolution Top Floats – Why?


Martin Sagendorfby:  Martin Sagendorf

We often think we see forces.  However, in reality, we only see the results of forces.  To understand forces we must believe in Newton’s Third Law.  It states that all forces can only exist in opposite pairs and be equal in magnitude.  And… what is very interesting is that Newton’s Third Law does not stipulate that the forces be of the same kind.

Also, by Newton’s Second Law: If the (net) forces are equal, there will be no accelerations (Fnet = ma = 0)… in other words… equal and opposite (net) forces create a state of equilibrium.  An interesting example of equal and opposite (and unlike-type) forces is that exhibited by a combination of opposed magnetic fields within a gravitational (force) field.  These two different (types) of fields interact purely as ‘force fields’ – only their forces matter… not their types.

Cosmic Magnetic Puzzle in Physics Demonstration Apparatus BookThe Cosmic Magnetic Puzzle exemplifies a combination of such forces: a barbell containing two ‘donut’ magnets supported in mid-air above stationary pairs of magnets – with an additional pair of donut magnets maintaining the horizontal location of the barbell. Read the rest of this entry »