Optics

Learning Targets• Sketch light rays based on the Law of Reflection.• Identify the differences between images and objects.• Explain the images in terms of direction (right-side-

up or up-side-down) and size.• Explain the types of images that can be viewed in

plane, concave, and convex mirrors.• Explain what refraction is and how it affects what we

see in lenses.• Explain the types of images that can be viewed in

concave and convex lenses.• Provide examples of applications of mirrors and lenses

in the real world.

Happy Wednesday!

• Learning Target: Explain the Law of Reflection.

• Bell-Ringer: – Give one example when reflection is

bad.– Give one example when reflection is

good.

Happy Tuesday!

• LT: Explain what reflection is.

• Bell-Ringer: How many cats are there?

Agenda

• Notes

• Reflection Stations Lab

• Hand back tests

Law of Reflection

• If light is not absorbed, it bounces. This is called reflection.

Billiards video

Starting θ= Ending θ

Law of Reflection

A different laser demo

WALL

Law of Reflection

In which direction will the laser beam go?

WALL

Fiber Optics

• Draw what happens to a laser as it goes diagonally down the graduated cylinder.

Fiber Optics

• Fiber optics work because:– Light travels in a straight line.– Light reflects off of inner surfaces.

Optics

• Optics is the study of vision and how images are formed. We will study the following:

– MirrorsPlane Convex Concave

– LensesConvex Concave

Objects and ImagesObjects are the real thing.Images are what we see.

ImageObject

Plane Mirrors

Mirrors

• Plane

• Convex

• Concave

Mirrors

• The images produced by curved mirrors depends upon where the object is located.

• Object is far Object is near

Happy Wednesday! 2/22

• Learning Target: Identify images and objects. Explain how light rays form images.

• Bell-Ringer: Why do you think this student wearing aluminum foil over his eyes? (Hint: They have pinholes in them!)

Happy Thursday! 2/23

• Learning Target: Use the Law of Reflection.

• Bell-Ringer: Why does this woman look so crazy in the mirror? (What must be true about the mirror?)

Happy Thursday!

• LT: Explain how convex and concave mirrors change images.

• Bell-Ringer: Why does this woman look so crazy in the mirror? (What must be true about the mirror?)

Happy Friday! 2/24

• Learning Target: Sketch light rays using the Law of Reflection.

• Bell-Ringer: – How do you thinkone-way mirrors work?

Happy Tuesday! 2/28

• LT: Describe images in concave, convex, and plane mirrors.

• BR: Why is thisbuilding in frontof a mirror?

What happens when light enters a different

medium?When light is traveling through air

and enters a different medium, three things can happen.

1. Light can be reflected (mirrors)2. Light can be refracted (lenses) 3. Light can be reflected AND

refracted! (total internal reflection)

Apr 19, 2023 Physics 1 (Garcia) SJSU

Transparent, Reflecting Surfaces

Water and glass are transparent but reflect some of the light striking their surface.

Can see inside the cab through the right window.Strong reflection of the sun on the left window.

Can see some of the riverbed through the water surface.

Apr 19, 2023 Physics 1 (Garcia) SJSU

One Way Mirror

One way mirror is just clear glass window.

Bright Room Dark RoomDiscussionRoom (Bright)

ObservationRoom (Dark)

GLA

SS

Reflected light from bright room masks transmitted light from the

darkened observation room

Law of Refraction

• When a beam of light passes into a new medium, it changes direction. This is called refraction.

• Just like with mirrors, lenses can distort an image so that the object looks different.

Refraction

Refraction

• Light refracts because it goes from one medium (air), which is thinner, to a different medium (water), which is thicker.

• Because light slows down in the water, it bends down.

• Laser Demo

Lenses

• Convex lenses are thicker in the middle than at the edges.

• Concave lenses are thinner in the middle that at the edges.

• What kind of lens is this?

Happy Monday!

• Learning Target: Use the law of reflection to make a laser hit a target.

• Bell-Ringer: The photographer is reflected in some-one’s eye. What kindof mirror is this?Explain how you know.

Happy Wednesday!

• Learning Target: Explain Learning Target: Explain how lenses produce how lenses produce different images.different images.

• Bell-Ringer: What are these raindrops doing the image of the leaf? Explain why you think it is doing this!

Agenda

• Finish Laser Challenge

• Refraction Stations Lab

• Finish Notes

Happy Thursday!

• Learning Target: Identify types of glasses and eye problems.

• Bell-Ringer: This student is lookingthrough a concave lens and his image is smaller.What kind of mirror affects images this way?

Agenda

• Finish Notes

• Lenses Lab

• Optics Reading

Lenses

• How much a lens is curved affects how much it magnifies an image.

Lenses

• When light passes through a convex lens, light focuses to a point. This is called convergence.

• When light passes through a concave lens, light spreads out. This is called divergence.

Lenses

• Some people need lenses to correct their vision.

• People who are far-sighted can only see things clearly if they are far away.

• People who are near-sighted can only see things clearly if they are near.

Happy Thursday!

• Learning Target: Identify the types of lenses and their uses in cameras.

• Bell-Ringer: Besides cameras, glasses, and our eyes, list three other common places that we use lenses.

• Optics Test: Tuesday!

Agenda

• Camera Dissection Lab

• Finish Optics Practice Worksheet

Happy Friday!

• Learning Target: Review for test.

• Bell-Ringer: – Some people cook food

using concave mirrors.Explain how this works.

Agenda

• Finish Optics Practice Worksheet• Convex Lens – go outside to burn paper• Video: How it’s Made – Contact Lenses• Demo: Blind Spot• Binder Organization

• Test Tuesday