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Hello! Welcome to Splo-On-The-Go, a series of short video clips, where we feature the
individual exhibits in the Splo museum in Second Life. I’m your guide, Opal Lei.
You have seen these before, probably at your boss’s desk. You may even have one at your
desk. In fact, it’s called the “Executive Ball Clicker” because of the sound it makes...
click, click, click, click....
In the scientific community, it’s called “Newton’s Cradle” named after Sir Isaac
Newton for his three laws of motion.
In real life, you pull back one of the end balls and release it to start the chain reaction.
At the Splo Museum in Second Life, you can start the balls swinging by touching this
sign.
Just like its real-life counterpart, only the end balls swing, and all the middle balls
remain stationary.
Now, why is that?
To understand why one ball coming in makes only one ball jump out, you must use both
the law of conservation of momentum and with the law of conservation of energy. Two of
the most important laws of physics.
If a system is closed or isolated from external forces,
the law of conservation of momentum states that the total linear momentum of the system
remains constant, and the law of conservation of energy states that
the total amount of energy in the system remains constant.
In Newton’s Cradle, the momentum and energy of the first ball is transferred completely
to the next ball, then to the next ball, then to the next, and the next, until it is released
in the final ball, which swings out to the same height where the first ball was released.
Then it comes back down (due to gravity) and transfers the momentum and energy through
the row of balls... in reverse.
Because the middle balls are already touching each other, they don’t swing; therefore,
there is no loss of momentum, as momentum and energy are transferred to the next ball.
Because the balls are made of steel, most of the energy is temporarily stored as kinetic
energy, and very little energy is lost as heat.
For a safe ride, sit on a middle ball. For a wild ride, sit on an end ball.
How cool is that?
Experience this exhibit and many more at the Splo in Second Life.