The number of crests that pass a given point within one second is described as the frequency of the wave and is measured in Hertz (Hz). These fields are perpendicular to one another in the direction the wave is traveling. ![]() Electromagnetic waves are formed by the vibrations of electric and magnetic fields. ![]() Likewise, energy from the electromagnetic spectrum has both particle-like and wave-like properties. Photons have no mass, but they do have momentum. Light is made of discrete packets of energy called photons that travel at the speed of light until they come into contact with other matter. Microwaves are a subset of radio waves.Įnergy is transported in waves. From highest to lowest energy levels, these sources from the Sun include gamma rays, x-rays, ultraviolet rays, visible light, infrared rays, and radio waves (see graphic below). Some have more energy and some have less. There are also parts of the electromagnetic spectrum that are less familiar to many of us. Sunlight is a part of the electromagnetic spectrum. Note: Students of all levels should be able to answer the first three questions and secondary level students should be able to answer the other questions too. It is measured in Hertz (Hz), the number per second.) How is wave frequency measured? (Frequency is number of complete waves passing per unit of time.How is wavelength measured? (Wavelength is measured in unit of distance between two wave crests.Looking at an illustration of the electromagnetic spectrum, what type of radiation has the shortest wavelength, and what does that signify? (Gamma rays have short wavelengths, and thus have very high energy, which can be damaging to life on Earth.).What about infrared radiation? How does it compare to visible light? (It has a longer wavelength and has less energy.).What is the energy of UV radiation compared to visible light? (UV has higher energy.) UV radiation has a relatively short wavelength, shorter than visible light.What does the length of the wavelength convey? (Short wavelengths have more energy, while long wavelengths have less energy.).What occurs to the length of the wave when the drill is slowed? (The wavelength lengthens.).What happens to the length of the wave when the drill speeds up, i.e., when more energy is added? (The wavelength shortens.).Experiment and have fun! Note: If you do not want the complication of using a drill, you can simply have students use a length of rope or a Slinky to demonstrate energy and wavelengths. You can also vary the speed and reverse the direction of the drill to get different wave effects. The less tension you apply, the more waves will appear. Plug in the drill, turn it on, and the demonstration begins.Ask a student to hold the end of the cord that is not at the drill at a distance so that the cord has some tension.Also, ensure that students helping with the demonstration are wearing safety glasses. Be sure to test it before you present it to your students. To ensure the safety of your students, it is imperative that the cord not break during the demonstration.The nail end should be put into the drill bit fitting and tightened securely with the chuck key.Slide the bent nail through the eye of the other swivel.This is the piece of cord that a student will hold during the demonstration. Tie the 1-foot piece of cord to one of the swivel holders.Attach a swivel to each end of the nylon cord.You will have to use a vise and pliers to accomplish this. Prior to the demonstration, you will need to bend a 20-penny nail as shown.Before presenting this demonstration, provide some background information on the electromagnetic spectrum.Two #2 fishing swivels (found in fishing section of sporting goods).Nylon cord cut one piece to 15 feet and another to 1 foot. ![]()
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