2.01 The Electromagnetic Spectrum

Transcription

1 2.01 The Electromagnetic Spectrum Introduction Tab: Electromagnatic energy travels in. Electromagnetic waves are waves. Hint: What kind of waves are electomagnetic waves? Energy from electromagnetic waves is called. Use the picture that is on the Introduction Tab to list the different parts of the electromagnetic spectrum in order from the lowest energy waves to the highest energy waves. 1) Radio waves (lowest energy) 2) 3) 4) 5) 6) 7) Gamma waves (highest energy) Which part of the electromagnetic spectrum can we see? Lessons Tab: The is the highest point on a wave. The is lowest point on a wave. The is the distance between two of the same points on a wave. Draw a wave below. Label the crest, trough and wavelength. The higher the frequency the more that is carried by the wave. The the wavelength, the higher the frequency of the wave. The the frequency, the greater the energy of the wave. List three examples of high energy waves that are harmful to living things:,,

2 2.02 Light and 2.03 Light Lab Read the Introduction tab, then move to the lesson tab. Click on the Lab button at the top of the screen for the virtual research station. Then click on the prism to watch the short video lesson on visible light. The only part of the electromagnetic spectrum that we can see with our eyes is. Visible light seems to be or colorless. Visible light can be separated out into different wavelengths. The individual wavelengths are seen as different colors. Visible light includes all of the different colors of the rainbow. Here they are listed in order from the longest wavelength to the shortest wavelength: red, orange, yellow, green, blue, indigo, and violet. In the visible light spectrum, red has the longest wavelength and violet has the shortest. Reflection Click on the polar bear pictures and define the terms below: Refraction- Absorption- Read below the polar bear pictures to complete the sentences below: Objects reflect light. The wavelength of light that is determines the color we see. If you see this as red, then all of the other wavelengths in the visible spectrum (orange, yellow, green, blue, indigo and violet) are being absorbed, and the wavelength of red is being. We see an object as black when all of the wavelengths in the visible spectrum are being. We see an object as white when all of the wavelengths in the visible spectrum are being. Go to the Activity tab and complete the practice activities before you attempt the assessment for Remember, you will also have questions about the information in 2.01 on the assessment for 2.02.

3 2.04 Sound Introduction Tab: The measures the distance from the same point in two waves. Most often, a sound wave is measured from to. is the number of waves that pass a point in a given time. Most often, frequency is measured by the number of waves that pass a point in one. Sound waves are waves. A longitudinal wave is a wave that has vibrations that are moving in the same direction as the waves itself (the vibrations caused by the wave are parallel to the direction the wave is traveling). The red arrow below shows the direction of the vibrations and the blue arrow shows the direction the wave is moving notice how the two arrows are parallel. Added Teacher Help: Sound is produced when an object vibrates. The vibrating object pushed the particles of matter next to it and causes them to compress (squeeze together). That compressed matter, in turn, compresses the matter next to it. The compression travels through the matter as a wave of energy. Sound waves travel in all directions away from their source. In the diagram above, the close coils are the compressions. The coils that are farther apart are relaxed. Longitudinal waves (like sound waves) must travel through a medium (any type of matter) and cannot travel in a vacuum (a place where there is no matter- like space). Lesson Tab: Frequency is measured in. Amplitude is the height of a sound wave. Amplitude is measured in.

4 Roll over the wave diagram to complete the next five statements: Frequency determines the. pitch means the wave is a high frequency wave. determines how loud wave is. amplitude waves sound loud. amplitude waves sound soft. Click on the terms reflection, absorption and refraction to complete the following statements: Reflection: When sound hits a surface some of it bounces back. When sound hits a hard surface a lot of sound is reflected back. When sound waves hit a smooth surface they are reflected in direction. When sound waves hit a rough surface they are reflected back in different directions. Absorption: Sound can pass through or into a material; this is called absorption, because the material is absorbing the vibrations of the sound wave as it passes through it or into it. In frequency waves more sound is absorbed. Refraction: When sound travels from one material to another it can change direction. How much it changes direction depends on the material that it is refracting off of. Sound travels faster in materials. Added teacher help: You have now studied two types of waves: electromagnetic waves and sound waves. Let s compare and contrast these two waves to see how they are similar and how they are different. 1. Both types of waves have a wavelength and frequency. Both types of waves can be reflected, refracted and absorbed. 2. Light waves are transverse waves and sound waves are longitudinal waves. 3. Light waves can travel through matter and in a vacuum (a place where there is no matter) like outer space. Sound waves can travel through matter, but can not travel in a vacuum. Think about that- this means that there is no sound in space! 4. Light waves and sound waves travel at different speeds through different materials, but sound travels much slower than light.

5 2.05 Heat Transfer and 2.06 Heat Transfer Lab Teacher Help: Heat is a form of energy. Heat can be transferred (moved) from one item or substance to another. For heat to be transferred, the items or substances must be different temperatures. Heat energy is always transferred from the warmer substance (the one with the higher temperature) to the cooler substance (the one with the lower temperature). Here is an example of heat transfer from higher to lower: Has an adult ever told you to close the door because you were letting all the cool air out? Yes, of course teens like to leave doors open and adults like low power bills! Scientifically speaking, you aren t letting all of the cool air out. You are letting the heat in. Heat moves from the area of higher temperature in this example outside to the area of lower temperature in the house. I don t recommend you share your new found knowledge when you get caught leaving the door open it s probably best to wait for a time when you get caught being good! Ok, are you ready to really get your brain working? Think about this: You take a can of soda from the pantry and a glass from the cabinet. You pour the soda in the glass and then add several pieces of ice. Here s the question: Is the ice cooling the soda or is the soda heating the ice? Call your teacher if you think you know the answer! You just might be able to get your oral assessment done early! Three types of heat transfer: is the transfer of heat from a warmer substance to a cooler substance that is in direct contact with each other. Conduction occurs when two items are touching. Heat transfers faster in certain objects than others. We call objects that transfer heat quickly conductors. Metals are good conductors. is the transfer of energy as electromagnetic waves. When electromagnetic waves travel through space it is called electromagnetic radiation. When electromagnetic radiation comes in contact with an object, the wave transfers the heat to that object. Examples: sunlight, heat from a camp fire, a microwave, a light bulb. is the transfer of heat in a liquid or a gas. Warmer gases or liquids are lighter than cooler gases or liquids. Because the warm gas or liquid is lighter it rises above the cooler gas or liquid. The cool gas or liquid sinks. This pattern continues in a somewhat circular motion and is called convection current.

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7 2.07 Energy Conversions and 2.08 Energy Conversion Excursion Energy is defined as the ability to do work. Sometimes it s easier to describe what energy does that what energy is. That is because, unlike matter, energy is not something you can see or touch. Energy is a property of matter, and all matter has it. Whenever a light bulb is lit, a turkey is roasted, an orchestra plays, a fan spins, a book falls off the shelf, or a fire burns, you can be sure that energy in one form or another made it happen. Energy comes in many different forms. While it can be transferred from one object or system to another or converted from one form to another, energy cannot be created or destroyed. This rule is known as the Law of Conservation of Energy. The law simply states that energy cannot be created or destroyed. Mechanical energy is the energy an object has because of its motion or position. There are two kinds of mechanical energy: kinetic and potential. Kinetic energy is the energy an object has because it is moving. The greater the speed and mass of an object, the greater its kinetic energy. Potential energy is energy an object has because of its position or shape. Other forms of energy include the following: Thermal energy(sometimes called heat energy) is the energy related to the temperature of a substance or object. Electromagnetic or Light energy is the energy carried by light and other kinds of electromagnetic waves. Chemical energy is the energy stored in chemical bonds. Electrical energy is the energy produced by electric charges. Nuclear energy is the energy contained in the nuclei of atoms. Sound energy is the energy carried by sound waves. Let s look at some examples of energy being converted from one form to another. Think about when you place a pot of water on the stove to boil. The electric energy that is being used to turn the stove on is being converted to thermal energy (heat) then the heat is transferred to the pot through conduction (remember that from 2.04?). Have you ever stood close enough to a stereo speaker to feel the sound coming out or to see the speaker vibrate? What you are seeing and feeling is sound energy being converted to kinetic energy. Remember,

8 kinetic energy is the energy of motion. When you feel the vibrations of air, you are feeling the sound energy being converted to kinetic mechanical energy because it is causing the air molecules to move. You have probably seen solar panels on top of a house before. These solar panels trap the electromagnetic energy and thermal energy that is in the sun s rays. When the panel traps this energy it is converting it to stored chemical energy. When the house needs electricity, the stored chemical energy in the solar panels is converted to electricity or electric energy. Our bodies also store chemical energy in the form of fat. When we eat a salad for example, our bodies are using the chemical energy that is stored in the plant (the plant got it s energy from the sun). Whatever is left over, our bodies store as potential chemical energy to use later. When we go for a run, our muscle cells will convert the stored chemical energy to kinetic mechanical energy so that we can move. Some of it is also converted to thermal energy, which is why we sweat!

9 Module 2 Review Questions 2.00 Welcome to Module The Electromagnetic Spectrum What types of waves make up the electromagnetic spectrum? List some examples of electromagnetic waves? What are the two different parts of a wave? high energy waves = frequency = wavelength There is a graphic organizer at the end of this lesson that you can save to refer back to, if needed Light/ 2.03 Light Lab Know the terms refraction, reflection and absorption as they refer to the movement of light waves. What conditions will cause light to bend? Visible light is seen as white light, however, when it passes through a prism, we see multiple colors, why does this happen? Why do we see color? 2.04 Sound What are sound waves and how do they travel?

10 Know how we measure waves: frequency, amplitude, and wavelength. The wavelength of a wave can be found by measuring what? How does a change in frequency or amplitude change the sound we hear? Know the terms refraction, reflection and absorption as they refer to the movement of sound waves Heat Transfer/2.06 Heat Transfer Lab Know how heat is transferred: Convection, Conduction and Radiation Why does heat move to an area of more energy to an area with less energy? Determine if the following would be examples of convection, conduction, or radiation, and why: * Cooking dinner in the oven * Touching a hot spoon with your hand * A heat lamp heating your food in a fast food restaurant How does the addition or removal of heat change the state of an object? (For example: changing from an ice cube, to water, to steam.) 2.07 Energy Conversions/ 2.08 Energy Conversion Excursion What does the Law of Conservation of Energy state? List and review the 7 types of energies discussed in the lesson. Describe chemical, sound and thermal energies in detail. Why is it so important to discover other forms of renewable energy, to replace fossil fuels? 2.09 Collaborative Project 2.10 Oral Exam

11 2.11 Module 2 Exam Students completing the Advanced coursework will complete the 2.11Advanced Exam instead of this exam. ***************** ADVANCED STUDENTS ONLY ***************** 2.04 Advanced: The Doppler Effect How do sound waves change when they are coming from a moving source? Be able to explain: frequency shift, blue shift, and red shift Advanced: What is Heat? What does a heating curve represent?

12 1. walk to your room; pick-up MP3 player, turn it on all represent chemical energy in body cells to mechanical/kenetic energy 2. Turn on the MP3 player stored chemical energy (also potential energy) to converted to electrical energy 3. Electrical energy in the MP3 player is converted to sound energy heard in head phones. 4. Smiling and all the muscles used to dance and sing represent chemical energy in cells to mechanical/kenetic energy 5. getting hot represents the mechanical energy in muscle movement converting to thermal energy 6. Turn on fan electrical energy converted to mechanical energy 7. Singing mechanical energy in muscles is converted to sound energy 8. Umbrella sitting in corner has potential energy that is converted to kenetic (mechanical energy) as it becomes an air guitar. You should be ready to do your assessment for this lesson. If you have any questions, please contact your teacher! There is a small file to help you with this assignment. If you need it, ask your teacher where you can find it!