Impress the judges at your science fair by presenting a battery-powered experiment.
Science fairs give students the chance to participate in authentic science by designing experiments in accordance with the rules of the scientific method. However, modern students are no longer limited to experiments with baking soda volcanoes, homemade compasses or moldy bread. In today's high-tech world, students of all ages can design battery-powered experiments that demonstrate the properties of electricity.
Generic vs. Name-Brand Batteries
You've probably seen all sorts of batteries on sale at the local discount store. Are these batteries really a great deal? Design an experiment to test generic discount store batteries against name-brand batteries. Purchase generic and name-brand batteries of the same size and expiration date. Install them in an electronic device, such as a portable CD player or flashlight. Turn the devices on. Make a note of when they begin showing signs of low battery and when they eventually stop working.
The Effect of Temperature on Battery Life
Many people store batteries in the refrigerator. What effect, if any, does a battery's temperature have on its output? For this experiment, you will need a voltmeter or multimeter, which are devices that measure voltage. Purchase at least three name-brand batteries with the same expiration date and place them in locations with extremely different temperatures. For example, put one in a hot car, another in the refrigerator, and a third at room temperature. After the batteries have attained the temperature of their environment, remove them and attach them to the voltmeter to determine which battery generates the highest output.
Fruit Batteries
Batteries contain acid that produces electricity when it makes contact with electrodes. This means that acidic fruit, such as citrus fruit, can be converted into a simple battery. For this experiment, you'll determine which type of fruit produces the most power by using different citrus fruits and a micro ammeter, which is a device that measures electrical current. Roll your fruit around on the table to get the juice flowing. Insert a copper nail and a zinc nail approximately two inches apart from each other in the fruit. Don't let them touch. Use a gator clip to attach one terminal of the micro ammeter to the zinc nail and the other to the copper nail. Record how much current each fruit produces.
Human Battery
Demonstrate why people should avoid mixing water and electricity. Begin by attaching a copper plate and an aluminum plate to separate blocks of wood. Use a gator clip to attach one terminal of a micro ammeter to the copper plate and another to the aluminum plate. Ask a volunteer to hold each plate in one of their hands. (Don't worry, it's completely safe.) Measure the electrical output on the micro ammeter. Next, have the volunteer wet his hands and repeat the experiment. What conclusions can you draw about how water affects the transmission of electrical current?
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