Watch 5 Videos and Answer Accompanying Questions

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Watch 5 videos and answer accompanying questions.

Watch videos: Characteristics of Waves Light Sound Energy Resources Use & Conservation Potential & Kinetic Energy and answer the following questions about each. Characteristics of Waves

1. What are waves?

2. What is the connection between waves and energy?

3. What do waves carry?

4. How are waves measured?

5. How do waves behave?

6. What are some examples of mechanical waves?

7. What are some examples of electromagnetic waves?

8. In order to be able to travel, what do mechanical waves need that electromagnetic waves do not need?

Explain.

9. How do we know that light is an example of electromagnetic waves, rather than mechanical waves? 10. What are the different parts of a transverse wave?

12. How are longitudinal waves different from transverse waves? 13. Using a slinky, can you demonstrate what compressions and rarefactions look like?

14. What is the difference between wavelength and frequency?

15. What is wave amplitude?

What does it tell us about the energy being carried by the wave?

16. What characteristic of waves is measured in Hertz?

What does that mean?

17. What is the formula for computing the speed of a wave?

18. What is reflection?

19. What is refraction?

20. What is diffraction? 21. What is constructive interference?

22. What is destructive interference?

Program Summary There are many different waves in the universe.

Some are mechanical, like ocean or sound waves, and some are electromagnetic, like visible light.

Waves carry energy from place to place through all sorts of substances, including air, water and the vacuum of space.

Mechanical waves need a medium, or substance,to travel through.

However,electromagnetic waves, like radio waves,microwaves, light and X-rays can travel through space without a medium.

Waves start out as disturbances, or vibrations,that are movements back and forth. When someone jumps into a pool of water,the splash disturbs or vibrates the calmness of the water, causing energy to move in waves across the whole pool. Waves move through matter but they cannot carry the matter itself. For example,a rubber duck in a pool floats up and over a passing wave; the wave does not carry the duck from one end of the pool to the other.

Waves can move in two different ways: Waves that move up and down with high points called crests and low points called troughs are called transverse waves.

Longitudinal waves travel in a back-and-forth vibrating motion, creating compressions where particles are squeezed together, and rarefactions where particles are stretched out.

Three characteristics of waves can be measured: amplitude, wavelength and frequency.

Wave amplitude is basically how big the wave is, telling us how much energy the wave is carrying. Wavelength is the distance between two crests or troughs. Some waves, like radio and TV waves, have long wavelengths; others like X-rays and gamma rays are delivered in short wavelengths. Frequency is the number of waves that pass a given point each second. This is measured using a unit called a Hertz. Humans can hear sounds from 20 Hertz to 20,000 Hertz, and dogs can hear up to 35,000 Hertz.

Light waves travel much faster than sound waves. Though lightning and thunder occur at the exact same time, you always see the lightning before you hear the thunder.

The speed of any wave is computed with the formula: speed = frequency x wavelength.

We also learn that waves can behave in one of three ways: they can be reflected, as in an echo bouncing off a surface; they can be refracted, as in a pencil that appears broken in a glass of water; or they can be diffracted, as in light or sound bending around corners. Waves that meet can combine energy or cancel each other out. This is called interference. Sound

Focus Questions:

1. How is sound defined?

2. How do sound waves travel?

3. Is outer space silent?

4. What are the components of a sound wave?

5. Why do we say that sound travels in longitudinal waves?

6. What is the difference between compression and rarefaction?

7. How do the terms ‘crest’ and ‘trough’ relate to compression and rarefaction?

8. What is amplitude?

How is it measured?

9. Why are sounds with high decibel levels dangerous? 10. What is wavelength?

11. How are the pitch and frequency of a sound related?

Give examples of sounds with high or low pitch.

12. How is sound frequency measured?

13. What is a hertz?

14. How does the human ear hear sounds?

15. Dolphins and bats use echolocation. What is it?

16. What is sonar?

17. What was learned from the “soundless bell” investigation?

18. What does it mean if a jet can fly at supersonic speed?

19. What does the density of a medium have to do with the speed of sound? 20. Can you explain why sound travels faster in stone and water than in air?

Program Summary Sound is energy that travels through a medium in waves. When an object moves back and forth,or vibrates, the molecules around the object also vibrate. Each molecule moves back and forth only a tiny distance, but it is enough to create areas where there are many molecules pushed close together, called compressions, and areas where molecules are spread far apart, called rarefactions. A compression is also called a wave crest, while a rarefaction is called a wave trough. Scientists measure sound waves in a number of ways. Amplitude is a measure of how loud a sound wave is and is measured in units called decibels (dB). Sounds that are louder than 120 decibels, like jet engines and rock concerts, are at a dangerous level for the human eardrum. Frequency is the number of waves that pass a given point each second and determines the pitch of a sound. As the frequency, or the number of vibrations increases, the pitch of a sound becomes higher.A low frequency sound is a rumble and a high frequency sound is a whistle. Sound wave frequencies are measured in units called hertz, or waves per second. Humans can hear sounds from 20 hertz to 20,000 hertz,while dogs can hear sounds up to 35,000 hertz. Dolphins can hear all the way up to 150,000 hertz! Humans can hear because of the vibration of the eardrum and bones in the inner ear. These vibrations are sent to the brain as nerve impulses where they are interpreted, identified and heard as spe- cific sounds. Sound needs a medium like air, water or stone in order to travel.The reason that outer space is so quiet, even though incredible explosions are constantly happening on the sun and on every other star, is that space is a vacuum. A vacuum has no atoms to vibrate; therefore, outer space is silent. No medium, no sound! An investigation confirms that a medium is necessary for sound energy to be transmitted. Sound travels at different speeds through different mediums. The denser the medium, the faster sound can travel through it. Sound travels almost five times faster in water than air and 20 times faster in solids like rock. The average speed of sound is 340 meters per second; anything faster is described as supersonic. Light

Focus Questions:

1. What is light?

2. What is a medium?

What are some examples in relation to light?

3. What are transverse waves?

How do they move?

4. How does the amplitude of a wave relate to its crest and trough?

5. How is a wavelength measured?

6. What is the electromagnetic spectrum?

7. What are some electromagnetic waves that can be found at a lower frequency than visible light?

8. What are some electromagnetic waves that can be found at a higher frequency than visible light? 9. Why do we often use the term light “rays”to describe light energy?

10. What happens when light energy is reflected?

11. What happens to light energy that is absorbed?

12. How fast does light travel?

Approximately how long does it take light rays from the sun to reach the Earth?

13. What happens to light when it strikes an opaque medium?

14. What happens to light when it strikes a transparent medium?

15. What types of objects are translucent?

16. What is refraction?

17. What colors make up the visible light spectrum?

18. How do we see colors?

Program Summary

We often take light for granted, without reflecting on what life without sunlight would be like here on Earth. Without light energy, we would not only be unable to see anything, but we also would not exist! Because light can move through the vacuum of space, energy from the sun can reach the Earth and be utilized in many ways. Light is moving energy that travels in a straight line via transverse waves through air or another medium. This means the energy moves up and down as it travels forward. A model of a typical transverse wave, showing the crest,t rough and amplitude is examined. Wavelength is shown to be the distance between two consecutive crests or troughs, and the frequency of a wave is defined as how many wavelengths pass a given point in a second. When light strikes a medium, it can be absorbed, reflected or passed through the medium. As light travels through any medium — whether it is a window or the air around you — it creates what scientists call a disturbance. When an object blocks the light, we say that object is opaque (like wood). When the light is only partially blocked, the medium is translucent (like a window curtain). When light is able to completely pass through an object, we say that medium is transparent. Light energy is radiation from the electromagnetic spectrum. This spectrum runs from low-energy waves such as radio, infrared, and microwaves to high-energy waves including ultraviolet, gamma and X- rays.In the middle is a small band of energy we know as the visible light spectrum, which includes only radiation with frequencies that humans can see, including all the colors of the rainbow (red, orange, yellow, green, blue, indigo and violet).

Energy Resources Use & Conservation

Focus Questions:

1. What is energy?

Why is it important for life on Earth?

2. What are energy resources?

3. How have energy resources been used over the past few thousand years?

4. How have humans used water as an energy resource over time?

5. What is biomass energy,and how has it been used throughout history?

6. Why was the Industrial Revolution an important turning point in the history of energy use and consumption?

7. What are fossil fuels?

How are they formed?

8. Why are fossil fuels considered to be a nonrenewable energy resource?

9. What are the positive and negative results of mining?

10. What is energy conservation, and why is it especially necessary now?

11. What is nuclear energy?

Describe fission and fusion.

12. What are the drawbacks to using nuclear energy as alternative to fossil fuels?

13. Compare renewable and nonrenewable energy resources. Provide examples of each.

14. How is wind power harnessed?

15. What is geothermal energy?

Where can it be found?

16. What is solar power?

How can solar power be used as an alternative energy source?

Program Summary

Energy use has changed a great deal since people relied solely on the sun, their own strong bodies or beasts of burden as energy resources. Long ago, people learned how to use water power to turn paddle wheels and wind power for transportation and irrigation. People learned to use the chemical energy stored in materials like wood to cook and heat their homes. Machines and technologies introduced during the Industrial Revolution of the late 18th century required the use of other energy resources, especially fossil fuels. Fossil fuels like coal, oil and natural gas are considered to be nonrenewable energy resources. Fossil fuel reserves have formed over millions of years from decaying plants and animals. The energy from the sun is the ultimate source of the chemical energy in fossil fuels. With the modern world depending upon coal, oil and gas for a majority of its energy needs and the prediction that the world will nearly double its need for energy resources in several decades, it is important to conserve energy and to investigate alternative energy resources. There are many renewable energy sources that are alternatives to fossil fuels. Nuclear energy is released when the nucleus of an atom is split by a process called fission ,or when atoms are combined through a process called fusion. Nuclear power is used to generate about 25% of the world’s electricity, but it has inherent risks , especially in the disposal of radioactive waste . Hydroelectric plants use running water to generate electricity. However, dams can flood nearby lands and can disrupt the normal flow of water, both of which negatively affect the environment . Wind power is increasingly being used as a clean source of renewable energy. Turbines harvest wind on wind- farms and generate electricity. Solar power is a promising, renewable energy resource that can be turned into electricity, and it is used in many tools, toys and even in home heating. Many other alternative energy sources like geothermal power, which draws upon the Earth’s natural heat, and biomass, which produces an alternative to gasoline, are being considered in the movement away from fossil fuel dependence. In our everyday lives, we can also work to conserve energy. Insulating, turning off lights and only using appliances like dishwashers when they are full are just some of the many ways people can limit energy use in their homes. Also, carpooling, bicycling and taking public transportation are effective energy - saving ideas. The Earth’s inhabitants must take a serious look at energy resources, use and conservation!

Potential & Kinetic Energy

Focus Questions: 1. What is matter?

2. How are energy and work related? 3. What is kinetic energy?

Give some examples.

4. What is potential energy?

How is it different from kinetic energy?

5. How can the kinetic energy of an object change if the total mechanical energy of the system remains constant?

6. Would you rather have a water balloon dropped on you from 1 meter above you or from 3 meters above you? Explain the role of potential and kinetic energy in dropping water balloons.

7. What is an energy transfer?

8. How is potential energy transformed into kinetic energy?

9. Why can a yo-yo be called an “energy transfer machine”?

10. Why is it true that as an object’s kinetic energy increases, its potential energy decreases?

Give an example.

11. How can you increase gravitational potential energy?

12. What is the formula for computing the gravitational potential energy of an object?

13. What factors are involved in determining the kinetic energy of a moving object?

14. What are joules?

15. What is the formula for computing the kinetic energy of an object?

16. If you roll two marbles down ramps, will they always travel at the same speed?

Why or why not?

Program Summary

Everything that moves — cars driving, kids on skateboards, waves crashing on the shore — uses mechanical energy in one of two states: kinetic or potential. Kinetic energy is active or moving energy. Potential energy is stored energy, or e n e rgy waiting to be tra n s fe r red into kinetic energy. If work is done on an object without any outside force involved, the total mechanical energy — the sum of the kinetic and potential energy — remains constant. When using a bow and arrow, the more you pull back on the bow, the greater the potential energy. When the arrow is released, the distance it travels will depend upon the amount of work that was done on the bowstring; in other words, the potential energy it was given by your pull. The greater the pull on the bow, the greater the kinetic energy of the moving arrow and the distance the arrow can travel. The higher and heavier an object is, the greater its potential energy. This is called gravitational potential energy, calculated by multiplying an object’s weight by its height of position. If two objects of different weights are about to be dropped from the same height, the heavier one has greater potential energy. Accordingly, when they are dropped, the heavier one has greater kinetic energy. If two marbles are rolled down a ramp from the same height toward a container, the heavier marble will move the container farther than the lighter one. However, raise the lighter marble higher on the ramp, and it will move the container just as far. Kinetic energy is measured in units called joules and can be calculated by multiplying an object’s mass by the square of its velocity, then dividing that number by two. Once you examine this formula, you will realize than in order to go twice as fast, you need four times the kinetic energy! Since potential energy is transformed into kinetic energy, an increase in mass or height of position will translate to greater kinetic energy. Understanding the relation–ship between potential and kinetic energy helps us to gather information about the world around us.