Teacher Guide. Including Student Activities. Module 7: Demonstrating Properties of Electromagnetic Radiation

Transcription

1 Teacher Guide Including Student Activities Module 7: Demonstrating Properties of Electromagnetic Radiation

2 ACTIVITY GUIDE Module 7: Demonstrating Properties of Electromagnetic Radiation Summary: Electromagnetic radiation we use it to talk on the phone, to cook food, and even to see! A television remote control is a great example of electromagnetic radiation at work. It uses a part of the electromagnetic spectrum, infrared radiation, to control your set from a distance. So what exactly is electromagnetic radiation? And what is this spectrum we keep hearing about? Is light a part of it? How does it all fit together? Electromagnetic radiation is energy transmitted in the form of waves. It is sometimes referred to as radiant energy. Electromagnetic waves are transverse waves, but do not require a medium to travel. As the name implies, they are composed of electrical and magnetic fields. For example, when you listen to the radio in your car, you do so courtesy of a type of electromagnetic wave, otherwise known as radio waves. When cooking, the microwave oven bombards its target with microwaves a type of electromagnetic wave that falls into the lower frequency range of the electromagnetic spectrum. Whenever you talk to a friend on your cell phone, you are actively using microwaves. We use incandescent and florescent lighting to illuminate our homes after dark. Where would medical science be without X-rays, yet another form of electromagnetic radiation? It is interesting to note that visible light, the only portion of the electromagnetic spectrum that can be seen with the naked eye, occupies only a tiny portion of the total spectrum. All other forms of electromagnetic radiation are invisible, but the effect of the energy they carry is not. Objective: Explain how waves can transfer energy. Describe several forms of electromagnetic energy including light, radio and X-rays. Module 7: Segment Length 9:51 minutes Page 2

3 Ohio Standards Connection Grade Nine Physical Science Benchmark G: Demonstrate that waves (e.g., sound, seismic, water and light) have energy and waves can transfer energy when they interact with matter. Organizer: Indicator 18: OSIC Nature of Energy Demonstrate that electromagnetic radiation is a form of energy. Recognize that light acts as a wave. Show that visible light is a part of the electromagnetic spectrum (e.g., radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays). Y2003.CSC.S03.G09-10.BG.L09.I18 Suggestions for the teacher: 1. Preview each segment before showing. 2. Prepare the class and gather all necessary materials. 3. Review segment content with class at each pause screen. 4. Begin lesson sequence activity after viewing lesson. Safety: Always be careful! Teachers and students should always exercise appropriate safety precautions and utilize appropriate laboratory safety procedures and equipment when working on science performance tasks. Page 3

4 Activity: The Science of Light Materials: prism multiple light sources, i.e. incandescent flashlight, sunlight, halogen light projection surface such as whiteboard or paper pen or marker to label lengths of colors Hand each student or group of students a prism and ask them if they know what it is. Give them time to use the prisms to break up the white light of the room, a flashlight, or sunlight coming into the room. If you have an overhead projector, set a prism on it to project the visible light spectrum onto the projection screen. You should see a spectrum similar to Illustration 1 when the light is projected. Notice how the bottom of the image is labeled. These numbers correspond to the wave length of the color, violet being shorter, red being longer. Illustration 2 represents the electromagnetic spectrum and shows the relative position of the visible light spectrum in the whole electromagnetic spectrum. Ask students the following questions: What do you see when you play with the prism? What are the colors of the "rainbow"? (Answer: Red, orange, yellow, green, blue, indigo and violet. Students may be familiar with the phrase "Roy G. Biv"; if not, you could introduce them to it.) Are these colors distinct, or do they seem to blend together? (Answer: They blend together. If students did not notice this, allow more time for exploration with the prisms.) Illustration 1. Page 4

5 Illustration 2. Ask students the following questions: What is the electromagnetic spectrum? (Answer: It is the entire range of all kinds of light, including light the human eye cannot see.) What is the light that humans can see called? (Answer: Visible light.) Visible light seems to occupy a large part or small part of the spectrum? (Answer: It is a very small part.) How does light travel? (Answer: It travels as waves.) What are the high and low points of a wave called? (Answer: They are called the peak and trough.) What is wavelength? (Answer: It is the distance between two nearest peaks or troughs.) How is wavelength important in defining the regions of the electromagnetic spectrum? (Answer: Different parts of the electromagnetic spectrum are made up of light of different wavelengths.) Page 5

6 Quiz: Properties of Electromagnetic Radiation From Illustration 2, what type of electromagnetic radiation has the shortest wavelength? Describe how wavelength and energy changes as you move from left to right along the electromagnetic spectrum. Page 6

7 Ohio Content Provider Recommendations Search String: waves electromagnetic waves microwaves electromagnetic spectrum Additional curricular resources can be found at the following websites using one or more of the search strings listed above to narrow your search. INFOhio Ohio Resource Center Ohio Department of Education Finding Additional Resources Using: D3A2 The D3A2 helps educators analyze data, and points them to resources such as lesson plans, assessments and activities designed specifically to address the academic need identified by the data. In addition to linking content to data analysis, educators will have general search capabilities to locate education content resources aligned to the Ohio s Academic Content Standards. Sample D3A2 Standard Search Results: What s the Frequency. ROY G BIV?: Retrieved from the Ohio Resource Center o Electromagnetic Spectrum Grade Nine: Retrieved from the Ohio Resource Center o p://ims.ode.state.oh.us/ode/ims/lessons/web_content/csc_lp_s03 _BG_L09_I19_01.doc Page 7