Where does light come from?

Common sources of light include the sun, light bulbs and lasers.

Is light necessary for us to see objects? Why or why not?

Yes. For our eyes to see objects, light must reflect off the objects and enter our eyes. Without light, we cannot see.

How does light travel from place to place?

Light travels in straight lines and is reflected off things (bounces off them).

A laser is a very narrow and concentrated beam of light.

Why does fog help us see laser beams?

Fog is made up of tiny particles that the laser light reflects off of. That reflected light is detected by our eyes.

What does the camera obscura model?

The camera obscura models a human eye.

Why is the image the camera obscura produces upside down?

This happens because light always travels in a straight line. BERT appears upside down because if you trace the path of light of his feet through the camera obscura, the feet end up on top. If you trace the straight path of light reflected off his head, it ends up at the bottom of the camera obscura. The same thing happens in our eyes!

If the image produced by the camera obscura is not in focus, what can be done to focus it?

Another lens can help focus the image, just like glasses that help people read.

Are other materials, besides a mirror, reflective? How do you know?

Yes, any object you can see must reflect light. If it did not reflect light you wouldn't be able to see it.

How do CDs, DVDs and Blu-Ray discs use light reflection to work?

CDs, DVDs and Blu-Ray discs are all read by small lasers that are found in the disc player. A laser shines on the disc and reflects off of it allowing the laser to “read” the information on the disc, which is translated electronically to music or movies.

Light Reflection & Vision

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What you will learn from this videoWhat you will learn

Light travels in a straight line and reflects off of things.
We can see because light reflects off objects and enters our eyes.
Our eyes do not produce light, they only detect it.

Discussion Questions
- Before Video
  Where does light come from?ANSWER
  - Common sources of light include the sun, light bulbs and lasers.
  Is light necessary for us to see objects? Why or why not?ANSWER
  - Yes. For our eyes to see objects, light must reflect off the objects and enter our eyes. Without light, we cannot see.
  How does light travel from place to place?ANSWER
  - Light travels in straight lines and is reflected off things (bounces off them).
- After Video
  What is a laser?ANSWER
  - A laser is a very narrow and concentrated beam of light.
  Why does fog help us see laser beams?ANSWER
  - Fog is made up of tiny particles that the laser light reflects off of. That reflected light is detected by our eyes.
  What does the camera obscura model?ANSWER
  - The camera obscura models a human eye.
  Why is the image the camera obscura produces upside down?ANSWER
  - This happens because light always travels in a straight line. BERT appears upside down because if you trace the path of light of his feet through the camera obscura, the feet end up on top. If you trace the straight path of light reflected off his head, it ends up at the bottom of the camera obscura. The same thing happens in our eyes!
  If the image produced by the camera obscura is not in focus, what can be done to focus it? ANSWER
  - Another lens can help focus the image, just like glasses that help people read.
  Are other materials, besides a mirror, reflective? How do you know?ANSWER
  - Yes, any object you can see must reflect light. If it did not reflect light you wouldn't be able to see it.
  How do CDs, DVDs and Blu-Ray discs use light reflection to work?ANSWER
  - CDs, DVDs and Blu-Ray discs are all read by small lasers that are found in the disc player. A laser shines on the disc and reflects off of it allowing the laser to “read” the information on the disc, which is translated electronically to music or movies.
Vocabulary
- Light DEFINE
- Light Reflection DEFINE
- Light Source DEFINE
- Reflecting Surface DEFINE
- Camera Obscura DEFINE
- Lens DEFINE
- Vision DEFINE
- Internal Reflection DEFINE
Reading Material
DIY Activity Guide
Lesson Plan
Lesson Plan
Teacher Guide
Assessment
Google Forms Online Quiz Game Quiz PDF Exit Ticket