JCJ Physics Project

"Lights Out"


The purpose of this project is to turn off a candle. First, one in our team will push a marble hanged on a ring stand. Then the marble will push a 20 g weight forward. Once the weight is knocked, a string that will be tied with the weight will fall. The string will have a cup of water tied at the other end. When the string falls down, the cup will go down as well. The light up candle will be standing next to the ring stand. As a result, the cup will drop all the water to the candle and turn off the light.

The model consists of three parts. These parts are used to reach our goal in trying to turn off a candle. One the ring stand with a pendulum hanging down from the stand, two the a ring stand with a lever that hold the string cup half filled with water, and three a candle that is lit. The model starts with the hanging pendulum the ball in placed half way in the air the ball comes downs and hit’s a block attached to the lever that’s has the cup of water. When the block is knocked down by the ball the string attached to the ball and lever drops down the cup filled with water and will fall on the candle that is beneath it. In our model we will keep track of energy by recording the time it takes to complete all the steps and weigh the model. We will then multiply the velocity and the weight and divide by two. This will give us the kinetic energy. To find the potential energy we will need to find the height of the model and multiply the weight and gravity together.

The energy transformations taking place in turning off the candle machine is Work, Kinetic energy and Power. It takes energy to push something and make it move. How much energy depends on the force exerted. The amount of work done on the ball hitting the cup depends on how much force is applied and how far the force causes the object to move. Work is equal to force times distance. The unit of work combines the unit of force with the unit of distance, the Newton-meter. We call a Newton-meter the Joule. The ball hitting the cup has energy of motion, or Kinetic energy, when it tips the water. The Kinetic energy of the ball depends on its mass and speed. Kinetic energy is equal to one half the product of the mass and the square of the speed. Power is the rate at which energy is changed from one form to another. The flame, which is turned off by the water is the rate at which work is done. It equals the amount of work done divided by the time interval during which the work occurs.


Making the 20 g weight to move

What we did was to push the marble with more force and to move the ring stand more forward.

Making the water to fall

What we did is to tie the string from the side of the cup. This made the cup fall sideways and to drop the water.

The position of the candle being far

When the water felt down, the water did not spilled into the candle. What we did is to move the candle more closely to the ring stand.

The final model constructed was a success, helping us achieve our goal in turning off the candle. This was not easily accomplished, taking several tries and methods to succeed. Our first problem that occurred was finding out a way to get the cup of water to fall on the candle. This was difficult because we needed object to hold the cup until it was time to release it. We also needed something to move the object in order to release the water on time. We accomplished this by using a five gram weight and attached a string to it connecting it to the cup of water. The cup of water was then attached to a ring stand at an angle in order to fall on the candle. Then we got another ring stand and attached string with a ball to move the object and allow the water to fall. Our model is very reliable working every time. There will not be any malfunctions or lose of energy because all the objects in the model are capable of with standing multiple trials and it does not rely on mechanical  devices.

Our “lights Out” project was not our original plan. The first plan was to light the candle but there were several difficulties in lighting up the lighter. We couldn’t find a way to pull the string hard enough so it would light up the candle. So it was easier to turn off the candle, but not that easy because we had to figure out a way to do so. We then found a way that would work after so many tries. The biggest challenge we had was figuring a way to tip the cup, so it would spill water on the flame. So when the cup finally spilled, turning off the candle, we were thrilled it had worked. What I liked most about this project was dividing the work and write-up among our group. I also liked the part when I got to light up the candle and then see it go-out. In our group we determined what materials we had and needed to get. Jackie brought in the candle and lighter, Janet brought in the string and block, and I got the ring-stand, cup and the pendulum. I think that doing research on Rube Goldberg machines and Goldberg himself, made the project meaningful, because we had to learn what a Rube Goldberg machine was and how it worked. Also learning a brief biography of Rube Goldberg was very educational.