A science project on insulators and conductors will teach you a lot about the electrical properties of materials. You can investigate which materials, such as metals, conduct electricity, while others, such as plastics, prevent its flow. By measuring a substance's electrical resistance, you can see how temperature and other factors affect the flow of electricity through different materials. If you use battery-powered equipment, your project will meet your school's safety requirements
Obtain an ohmmeter from your school's science lab and learn how resistance, measured in units called ohms, affects a material's ability to conduct electricity. Measure the resistance of everyday objects such as a wood ruler, a pencil lead, a penny or a cup of tea. Think about why these things have different electrical resistances, formulate a hypothesis, and test it out.
More advanced students may wish to investigate superconductors. These are substances that exhibit no electrical resistance. While normal materials, such as metals, become superconducting at extremely low temperatures, a few enter that state at liquid nitrogen temperatures. You'll need special permission to work with liquid nitrogen, and you may have to ask a specialist to handle it for you.
A material's temperature affects how it conducts electricity. In a flashlight bulb, for example, the metal filament becomes very hot as it glows brightly enough to produce light. Its electrical resistance is lower when it's cold and higher when it's hot. Diodes and transistors, on the other hand, sometimes exhibit the opposite effect, having less resistance at higher temperatures.You can measure this difference and plot a graph depicting how resistance changes with temperature.
Pure water is a good insulator, preventing the flow of electrical current. As soon as you add impurities to water, however, it begins to conduct electricity. Start with a container of pure water and measure its resistance with an ohmmeter. Add a small amount of a substance, such as salt, and measure the resistance again. Keep adding salt and measuring until the salt can no longer dissolve in the water. Graph the resistance of the water versus the amount of salt you put in it.
Different materials have been used as electrical insulators, including leather, glass, plastic and rubber. Investigate why insulators stop the flow of electricity, why you'd use different insulators in different situations, and why they're so important to electrical safety. Find out how an insulator's size, shape and length affects its electrical properties.
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