June 2019 archive

Rube Goldberg Assignment: The Kettle Krasher

Objective: Turn off the Kettle


The Steps – Explained: 

A. To activate the machine, Emily comes over and uses an elastic band to hit the rubber ball.

B. The ball rolls down a cardboard ramp.

C. The ball knocks over four books standing close to each other.

D. The books hit two marbles (metal balls), causing them to roll down the track and fall into a plastic cup.

E. The plastic cup is attached to a pulley. Therefore, when the marbles fall into the cup, the increase in weight of the cup causes it to descend.

F. Attached to the other end of the pulley is another plastic cup. This works the same way as classical pulleys do. This cup ascends because it weighs less.

G. When the second plastic cup ascends, it pulls the cardboard stopper attached to it that is preventing the tennis ball from rolling down a track. Once the stopper has been pulled away, the tennis ball rolls down the track.

H. The tennis ball drops into a plastic cup, attached to another pulley. The cup drops with the weight of the tennis ball.

I. On the other end of the pulley is a cardboard stopper, preventing a plastic clock from falling down. When the tennis ball falls into the cup in the previous step, the cardboard stopper is removed.

J. The plastic clock rolls down a small track and then glides on a string attached to a track on the counter and the ceiling.

K. The plastic clock hits the tennis ball causing the ball to roll down the track.

L.  At the end of the track, the tennis ball falls onto the switch (due to gravity) of the kettle and shuts it off.

Types of Energy: 

Mechanical – Books Falling

Mechanical Energy is the movement of objects or substances from one place to another.

Gravitational –  The Pulleys

Gravitational Energy is the energy an object has because of its position of height.

Thermal – The Kettle

Thermal Energy or heat energy, is the internal energy of a substance due to the vibration of atoms and molecules making up the substance.

Electrical – The Kettle

Electric Energy is the energy from the flow of electric charge.

Elastic – Rubber Band

Elastic Energy or stored mechanical energy is stored in an object by the application of force.

Energy Transformations: 

Elastic Energy ➡️Gravitational Energy

The rubber band hits the ball, causing it to roll down the track. The ball rolls down the track due to the energy emitted from the rubber band and gravity.

Mechanical Energy➡️Gravitational Energy

The mechanical energy of the cardboard stopper being pulled away causes the tennis ball to roll down the track and into the plastic cup. The tennis ball rolls down due to gravitational energy.

Gravitational Energy➡️Thermal Energy

The gravitational force of the tennis ball, causes it to land on the switch and turn on the Kettle, that is producing thermal energy.