1.2.3 Explore_ Electromagnetic Radiation - Google Docs.pdf...

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Electromagnetic Radiation In this activity, you will research and evaluate claims about how certain types of electromagnetic radiation (EMR) affect matter when they are absorbed. You will start by searching for published materials (such as books, journal articles, web resources, advertisements, and videos) that make claims about the effects of EMR on the matter that absorbs it. Then you will find and use reliable scientific sources to analyze whether the claims are valid. You will need to evaluate the reasoning behind each claim and the empirical evidence that supports or refutes it. Then you will decide whether you think each claim is valid. You will present your findings in the form of a research paper. Background Electromagnetic radiation (EMR) is the transfer of energy by electromagnetic (EM) waves. The amount of energy transferred by EM waves varies according to the frequency of the waves. The higher the frequency of a wave, the greater its energy. The term electromagnetic spectrum refers to the entire range of EM waves, from extremely high-energy waves (gamma rays, X-rays, and ultraviolet) to very low-energy waves (infrared, microwaves, and radio). EM waves can travel through a vacuum, unlike mechanical waves. All EM waves travel at the same speed in a vacuum — 3 × 10 8 m/s (the speed of light) — and at slower speeds through matter. Some of the kinetic energy of EM waves transforms into other forms of energy as the waves pass through matter. Since energy is the ability to cause change, EMR can cause changes in the matter it passes through. People use EM waves for many purposes, such as communications, lighting, and medical procedures. X-rays and light from lasers, for example, have many applications in medicine. However, they can also cause damage to body tissues. In addition, people encounter many types of EMR in their surroundings. Some of this EMR — such as ultraviolet radiation, which causes sunburns and skin cancers — is harmful. Therefore, much scientific research has been done on the effects of EMR on many types of matter. Many forms of EMR are impossible to observe and research without specialized equipment. This has made it easy for groups to promote products based on unsupported claims about how EMR affects the human body and other forms of matter. These false claims are made in order to sell products, promote a belief system, or reach some other goal besides the unbiased practice of science. Conduct Research (15 points) Evaluate claims about the effects that different frequencies of electromagnetic radiation have when absorbed by matter. 1. Conduct research to identify claims made about the effects that certain frequencies of EMR have when absorbed by matter. Find two examples from published sources. Write brief descriptions of your two examples. (5 points) A) What parts of the EM spectrum are being used? Compare them in terms of wavelength, frequency, and energy.

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