CURVED MIRRORSChapter 5, Section 7

HW: p 555 PTG 5.7 #1-6, 8 Learning Objectives

Compare and contrast real and virtual images

Describe focal length Success Criteria

Identify the focal point and the focal length of a curved mirror

Observe virtual images in a convex mirror

Observe real and virtual images in a concave mirror

Measure and graph image distance vs. object distance for a concave mirror

Do Now:Write LO and SC

on new left pagep 548

WDYS/WDYT Agenda:

Do NowLab 5.7 Summary

Investigation 5.7 #1 and #2

#3-9

#10-12

Record observations with concave and convex mirror

Class demo under document camera. Students record responses for #8 and #9

Students complete using same steps as 3-9.

Investigation 5.7 continued #13-15 Teacher

demo with finding image

#16 -17 Students use same process with object that is outside window

Students record observations in data table like the one found in #14

Students record observations in journal and thoughts on convex mirrors

HW: p 555 PTG 5.7 #1-6, 8 Learning Objectives

Compare and contrast real and virtual images

Describe focal length Success Criteria

Identify the focal point and the focal length of a curved mirror

Observe virtual images in a convex mirror

Observe real and virtual images in a concave mirror

Measure and graph image distance vs. object distance for a concave mirror

Do Now:How do the images

of concave and convex mirrors compare? How do you know?

Agenda:Do NowPhysics Talk 5.7Summary

Physics Talk 5.7 What is a real

image?

What is a virtual image?

An image that will project on a screen – it has an actual image location

An image that will not project on a screen – the image only appears to be coming from that location

Physics Talk 5.7 What is a concave

mirror?

What is a convex mirror?

A curved mirror in which the reflecting surface caves in

A curved mirror in which the reflecting surface bulges out

Physics Talk 5.7 What is the

relationship between the angle of incidence and angle of reflection?

The angles are equal. This allows us to draw ray diagrams that illustrate how the light is moving

Studying Ray Diagrams Illustrating light 3 rays

coming toward concave mirror

1. This ray is parallel to principal axis. This same ray reflects through the focal point

2. This ray approaches the center of the mirror and reflects with the same angle

3. This ray goes through focal point first, hits the mirror, and reflects parallel to the principal axis

All 3 rays must be present in ALL ray diagrams!!!

Studying Ray Diagrams The place where all

3 rays meet is the top of the image

The rest of the image is between that point and the principal axis

All 3 rays must be present in ALL ray diagrams!!!

Study the Diagram This is a similar

situation, except the object is farther from the mirror

This demonstrates the different sized images you saw in the lab

Find and name all three rays

Diagram with Virtual Image

If the object is closer to the mirror than the focal length, it will produce a virtual image

Diagram with Virtual Image

1. This ray runs parallel to the principal axis and through the focal point

2. This ray goes from the object in the angel of the focal point and will reflect parallel to the principal axis

3. This ray will leave the object and reflect off the mirror where the principal axis and mirror meet with the same angle

Where do the rays meet?

Physics Talk 5.7 Where did the rays

meet in the diagram?

Where can the image be found?

The rays never met, which means there is no real image!

The virtual image appears to be behind the mirror where the extended rays meet

Physics Talk 5.7 How does this

compare to plane mirrors?

With plane mirrors, the virtual image is identical in size to the object

With curved mirrors, the virtual image can be a different size

Physics Talk 5.7 How does this work

for convex mirrors? Find the rays

What kind of relationship is it? We can tell by

looking at the graph, that it has the shape of a hyperbola.

This shape tells us we have an inverse relationship between object distance and image distance

End of Section Questions Checking Up p 552 What do you think

now? p 554

Practicing Ray DiagramsPTG #7, 9-12 as a class

Ray Diagram Practice Worksheet