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Figure 1: A complete circuit is shown with the energy traveling around in the hand.

HOW DO UFO BALLS WORK
The UFO ball is an interesting science toy that many science teachers purchase. It lights up, and makes cool sounds. But looking at the lights flashing and the speaker making noise, what is the scientific reasoning for the UFO ball to operate? Well, UFO balls are powered by many circuits that are all stored inside of the ball. But, the circuits contained inside are not completed. That final step is up to you. On the sides of the UFO ball, there are strips of metal that attach to the two circuits. One of the circuits controls the light of the UFO ball and one controls the sounds. When you touch both of the circuits with the appropriate hands, the lights will activate, causing an interactive toy that will keep children busy. Since there are two series circuits, they can also be considered as parallel circuits. A parallel circuit is a circuit in which the loads are connected side by side. In the UFO ball, the loads are either the speaker or the LED light. The parallel circuits work well because if one series circuit was to stop, the LED light or the speaker, the other would still be able to function properly without the other one. The UFO ball will not work if the circuit is not complete. If you touch the UFO ball one side with your hand and one side with someone else’s hand it will not operate. This occurs because when you and the other person are touching the ball it it’s a full circuit since half of the circuit is coming from you, half from the other person. But if you touch the skin of the other person it will operate because the circuit is complete. In, the UFO ball works because the operation of the parallel and series circuits inside of the ball being powered by the circuitry, and will only operate properly only if the entire circuit is complete.

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Figure 2: The circuit isn't complete because the energy dies off since they are not connected.


Series Circuits
Series circuits are individual circuits that work off of themselves. The series circuits work independently and if anything in the circuit fails, the rest of the circuit fails. In the UFO ball, the series circuits are the two little cylinders. These cylinders both have a purpose. The first cylinder’s job is to create sound through the speaker underneath. The series circuit is connected to the silver strip and the speaker. When the strips are touched, the sound operates, since the energy of the load travel through the speaker, wire and the hand. The other series circuit would be the LED light’s circuit. The LED would also be functioning properly, since together they are a parallel circuit (see Related Topic 2) The LED would function, causing the sound, but if someone cut the wire connecting the speaker to the circuit, the LED light would still operate properly, the only thing that changes is that the circuits are no longer considered parallel circuits.

Parallel Circuits
A parallel circuit is two circuits that are both operating in the same device. In the UFO ball, the parallel circuits are the LED light and the speaker’s load. The parallel circuits MUST have both circuits functioning properly for it to be considered a parallel circuit. If a circuit does fail, then the parallel circuit is then considered a series circuit (see related topic 1). The circuits will properly activate if the circuit is complete. If you use one hand, then the parallel circuits will be complete, (see figure 1). But of you use two different people, the circuit isn’t complete because the two people are not complete since they are not completely connected, (see figure 2). But, if one of the people touch the other one’s skin, then the circuit is complete, and both the parallel and series will operate properly.
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Figure 3: The Energy travels through the complete circuit traveling through the two bodies.

Glossary
UFO Ball- A children’s interactive science toy that lights up and makes sounds.
Circuit- A roughly circular line, route, or movement that starts and finishes at the same place.
LED Light- A light-emitting diode (LED) is a semiconductor light source. LEDs are used as indicator lamps in many devices.
Load- The main energy source in a circuit.

Citations

Holt, Rinehart and Winston. ‘Electric Circuits’. Electricity and Magnetism. Holt, Rinehart and Winston: United States of America, 2007. Print.
Thelwell, Andy.www.andythelwell.com/blobz/. Andy Thelwell, Unknown. Web. 9/20/12.
Scherz, Paul. Practical Electronics for Inventors .McGraw Hill: New York, 2000. Print.

series circuit. Art. Encyclopedia Britannica. Web. 27 Sept. 2012. <http://school.eb.com/eb/art-158684>.

Wikipedia. http://en.wikipedia.org/wiki/Electronic_circuit. Wikipedia, 9/18/12. Web. 9/20/12.