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3. Unit 14 Lesson 3 What Is Light?
Light Energy
Light is a form of energy that moves in waves and can travel through space.
Light waves are transverse waves.
As these waves move forward, energy is carried perpendicular to their forward motion, forming an S shape.
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4. Unit 14 Lesson 3 What Is Light?
Light Energy
Light spreads out in all directions, traveling in straight lines from its source.
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5. Unit 14 Lesson 3 What Is Light?
Light Energy
Light can move through a vacuum because it does not need matter to transmit energy.
Light travels faster than anything in the universe, taking only about 8 minutes to travel 149 million kilometers (93 million miles) from the sun to Earth.
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6. Light Energy Unit 14 Lesson 3 What Is Light?
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7. Light Energy Unit 14 Lesson 3 What Is Light?
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8. Light Energy Unit 14 Lesson 3 What Is Light?
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9. Now You See It, Now You Don’t
Unit 14 Lesson 3 What Is Light?
Now You See It, Now You Don’t
The electromagnetic spectrum is a range of light waves organized by frequency and wavelength. It is invisible to the eye.
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10. Now You See It, Now You Don’t
Unit 14 Lesson 3 What Is Light?
Now You See It, Now You Don’t
At one end, waves have long wavelengths and low frequencies, including infrared waves, microwaves, and radio waves.
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11. Now You See It, Now You Don’t
Unit 14 Lesson 3 What Is Light?
Now You See It, Now You Don’t
At the other end, waves have short wavelengths and high frequencies, including ultraviolet rays from the sun and X-rays.
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12. Now You See It, Now You Don’t
Unit 14 Lesson 3 What Is Light?
Now You See It, Now You Don’t
Light that the eye detects is called visible light.
Visible light forms one very narrow section in about the middle of the electromagnetic spectrum.
Visible light looks white to our eyes, but it is actually made up of many colors. Red has the longest wavelength and violet has the shortest.
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13. Now You See It, Now You Don’t
Unit 14 Lesson 3 What Is Light?
Now You See It, Now You Don’t
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14. Now You See It, Now You Don’t
Unit 14 Lesson 3 What Is Light?
Now You See It, Now You Don’t
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15. Laser Light A laser is a beam of light focused in only one direction.
Unit 14 Lesson 3 What Is Light?
Laser Light
A laser is a beam of light focused in only one direction.
Laser beams contain only one wavelength of light. This feature makes a beam of laser light very precise and powerful.
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16. Laser Light Unit 14 Lesson 3 What Is Light?
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17. Unit 14 Lesson 3 What Is Light?
Laser Light
Artists use lasers to make three-dimensional images called holograms.
Doctors use lasers as surgical tools.
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18. Unit 14 Lesson 3 What Is Light?
Laser Light
Lasers can also be used to cut steel in factories and metal shops.
Laser pointers help teachers in classrooms.
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19. Unit 14 Lesson 3 What Is Light?
Laser Light
Lasers must be used safely. Looking into the source of a laser’s light can damage the eyes.
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20. Laser Light Unit 14 Lesson 3 What Is Light?
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21. Laser Light Unit 14 Lesson 3 What Is Light?
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22. Laser Light Unit 14 Lesson 3 What Is Light?
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23. Unit 14 Lesson 3 What Is Light?
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24. Unit 14 Lesson 3 What Is Light?
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25. Unit 14 Lesson 3 What Is Light?
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