Robogals Science Competition Rollerball Model
Why did you choose this project?
I was originally doing a simple marble run through school and I decided to create a significantly altered version of the school project which was to create a simple marble run that took 20 seconds. I designed a Rube Goldberg machine so that I could explore forces and energy, but I wanted to extend myself further and also learn about electricity. I did this by adding lights to my model that were triggered by switches.
What did you enjoy most about the project?
I most enjoyed learning about electricity and creating circuits triggered by mousetraps and tilting pipes. I also thoroughly enjoyed putting the model together and brainstorming ways to fix problems.
What have you learned from the project?
I have learnt a large amount about circuitry and electricity, including how to draw circuits using correct symbols and how to put together and solder a working circuit controlled by switches. I also learnt about forces, primarily friction and gravity. I used this knowledge while I was adjusting the surfaces and the slopes that I used to change the length of time my Rube Goldberg machine took.
How did your parent or mentor help you?
My mentor helped me in a few ways. Firstly, he taught me about electricity and taught me how to solder circuits together. As my model involved a lot of construction, my mentor helped me with drilling holes, sawing various materials and using power tools including the nail and staple guns. My mentor also taped parts of my video.
For the intermediate age group (9-12): briefly explain the underlying scientific theories behind the project, why you chose this method and equipment, and whether the experiment is repeatable and why?
Friction and gravity played a major role in this experiment. If you take a marble and drop it from about 70cm, it takes less than 2 seconds to reach the ground. This is caused by gravity, an attraction force that pulls all objects towards each other. Gravity has only a noticeable effect on extremely large objects such as the earth. In my project, I not only needed to use gravity to make the marbles roll but I also needed to slow the force of gravity. I did this using friction. Friction is the force that is created when two surfaces roll or slide over each other. More friction is created between surfaces that have more bumps and hollows in them. To make sure that the marbles and ball bearings took the correct amount of time to complete the Rube Goldberg machine I used a variety of different surfaces including sandpaper and plastic. Another significant part of my model was electricity. The circuits I created began with the batteries; they were followed by a negative (black) and a positive (red) wire coming from the correct ends of the batteries. I used LEDs in my project, they are light – emitting diodes and they glow when in a complete circuit. Then I attached the LEDs, making sure not to attach any positive wires to any negative wires as this would create a short circuit. If a short circuit occurred, it will stop the flow of electricity through the larger circuit meaning that no LEDs will glow. To create switches for these circuits, I cut one of the wires leading to the battery, and then I placed the two new ends of the cut wires on the project where the marble or the ball bearing will trigger a connection between the wires; this completed the circuit and switched on the LEDs. The method I used to create my model meant that I had quite a lot of freedom during the building process. Because I was making a complicated model, it was hard to draw a perfect plan before I began so I merely drew some ideas. As I became closer to completing my model I was able to focus on finer details, to perfect the timing. This experiment would be repeatable and it may have the same outcome each time but it is highly likely that the path taken to get to completion would be very different. This is because the experiment does have a clear goal; to explore forces, energy and electricity by creating a Rube Goldberg machine. The final product also needs to run for 19.5 to 20.5 seconds. These goals are both achievable but it would be hard to reach them by replicating this exact model again.
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