Hand Out for Optics

8/22/2019 Hand Out for Optics

1/19

Light and geometric Optics?

Shed a Little Light on

J effrey Major Science Department HeadThames Valley District School Board

[email protected]


2/19

laser

waters surface

WHAT DO YOU

T H I N K ?

1 4

2 5

3 6 A luminous object such as a candle radiates lightin all directions.

Agree/disagree?

Microwaves travel at the speed o light.

Agree/disagree?

This diagram accurately shows how an image appears

in a makeup mirror.Agree/disagree?

A ull-length mirror is necessary in order or you to see

your whole body in refection.

Agree/disagree?

This diagram accurately shows a laser beam refecting o

a curved mirror.

Agree/disagree?

This diagram accurately shows light refecting o the

surace o very still water.Agree/disagree?

Many of the ideas you will explore in this chapter are ideas that you have already

encountered. You may have encountered these ideas in school, at home, or in

the world around you. Not all of the following statements are true. Consider each

statement and decide whether you agree or disagree with it.

What Do You Think? 461

NEL


3/19

Using Light Rays to Locate an ImageLight rays and the laws o reection help determine how and where an

image is ormed in a plane mirror. A light source radiates millions o light

rays in all directions, but you are only concerned with the rays that actually

strike the mirror and are reected into your eyes. Tese rays are reected of

the mirror, with the angle o incidence being equal to the angle o reection.

o learn more about producing multiple images o an object in plane

mirrors, try the activity below.

SKILLS MENU: Predicting, Observing, AnalyzingEquipment and Materials: two plane mirrors; two mirror

supports; ruler; protractor; a die; paper; pencil

1. Place the two mirrors at right angles to each other at the

top of the sheet of paper. Place the die directly in front of

the right angle ormed by the mirrors (Figure 3). Record how

many images you see in the mirrors.

2. Gently move one o the mirrors, changing the angle between

the two mirrors, until you see our complete images. Draw

lines on the paper at the base o the two mirrors. Measure

and record the angle between them.

3. Now gently move one o the mirrors until you see fve

images. Again, draw lines on the paper at the base o the two

mirrors. Measure and record the angle between them.

4. Based on your previous results, predict what angle between

the mirrors would produce six images, then seven, eight,nine, and so on.

5. Continue moving the mirrors, counting the total number of

images, and measuring the angle between the mirrors as

long as you are able to.

A. How many images were visible when the mirrors were at

right angles to each other? T/I

B. Use your knowledge o light rays to explain why this number

o images was ormed. K/U T/IC. What was the angle between the mirrors for four images? T/I

D. What was the angle between the mirrors or fve images? T/I

E. Were your angle predictions correct or six, seven, eight, and

nine images? I not, explain why. T/I

F. What was the total number o images that you were able to

count? Why were you not able to exceed this value? T/I

G. A hall o mirrors in an amusement park seems to produce an

infnite number o images when you look into it. This eect is

also commonly seen in elevators that have two plane mirrors

on opposite walls (Figure 4). T/I C A

(a) Suggest a reason why elevator designers use this eect.

(b) On a piece o paper, draw two plane mirrors that are

parallel to each other. Add light rays to show how this

set-up can produce multiple images.

TTRY THIS PRODUCIngIMAgES,AnDMOREIMAgES,AnDMOREIMAgES

Figure 3

Figure 4 Multiple images produced by parallel plane mirrors

11.7 Images in Plane Mirrors 489NEL

SKILLSHANDBOOK

3.B.


4/19

www.PrintablePaper.net


5/19

PERFORM AN ACTIVITY

PurposeTo explore the characteristics o images produced by

converging and diverging lenses.

Equipment and Materials converging lens with support

diverging lens

metre stick with two supports

candle with holder

paper screen and holder

second sheet of paper or a small piece of

cardboard

chalk that can be easily erased

Procedure

Part A: Locating Reference Positions

for a Converging Lens

1. Place the two metre stick supports under the

ends o the ruler.

2. Place the converging lens in the lens support and

place the lens and lens support in the middle o

the ruler (at the 50 cm mark).

3. Aim the metre sticklens assembly at a relatively

distant object that is transmitting external light

in the classroom when the lights have beenturned of. Suitable objects are the slats o an

open window blind, a window rame, or a door

rame in a room with a window. Make sure that

you are as ar away as possible rom this distant

object. Move the sheet o paper back and orth

behind the lens until you see as sharp an image

o the distant object as possible. Mark this

location on the ruler as F(principal ocus). Also,

mark in twice this distance (2F) rom the lens.

4. Mark these same positions on the opposite side

o the lens, but mark them as F (secondary

principal ocus) and 2F respectively.

Part B: Locating Images in a

Converging Lens

5. Place a lit candle at these ve positions:beyond 2F , at 2F , between 2F and F , at F ,

and between F and the lens. Move the paper

screen back and orth until you locate an image.

Figure 1 shows the setup or this procedure.

Describe the characteristics o each image (size,

attitude, location, and type) that you were able

to locate. Use 2F and F as reerence points

when describing the image location. Record your

observations in a table similar to Table 1.

Note that you may need assistance rom your

teacher or the last two object locations: at F

and inside F .

When using a candle, tie back long hair and loose clothing.

Place a piece of paper under the candle to catch any

falling wax.

Be careful when moving the candlethe wax is hot.

SKILLSHANDBOOK

1.B., 3.B.

Locating Images in Lenses

Lenses are used in many optical devices such as cameras and eyeglasses.

In this activity, you will examine the images produced in converging

and diverging lenses. Remember to pay particular attention to the ourcharacteristics o images: size, attitude, location, and type (SALT).

13.2

Object

location

Size of

image

Attitude

of image

Location

of image

Type of

image

beyond 2F

at 2F

between2F and F

at F

inside F

Table 1 Image Characteristics in Lenses

Questioning

Hypothesizing

Predicting

Planning

Controlling Variables

Performing

Observing

Analyzing

Evaluating

Communicating

SKILLS MENU

554 Chapter 13 Lenses and Optical Devices NEL


6/19

6. Move the candle back to its original position

beyond 2F . Now cover hal o the lens with the

second piece o paper or cardboard. Locate and

describe the image.

7. Move the second piece o paper or cardboard to

cover hal o the flame. Locate and describe the

image.

Part C: Locating Images ina Diverging Lens

8. Replace the converging lens with a diverging

lens. Attempt to nd an image on the screen.

Now lookinto the diverging lens, locate

the image o the candle, and describe its

characteristics. Move the lens back and

orth to see i there is any change in image

characteristics. Record your observations.

Analyze and Evaluate(a) Where must an object be located or a

converging lens to produce a real image? T/I

(b) What happened to the size o the real image as

the object was slowly moved toward the lens

rom its original position beyond 2F ? T/I

(c) What was the only location where the

converging lens did not produce an image? T/I

(d) Where must an object be located or a

converging lens to produce a virtual image? T/I

(e) What were the characteristics o the image in the

diverging lens or all object locations? T/I

() Why did you not have to ollow the same

procedure or the diverging lens as you did or

the converging lens? T/I

(g) Why were you still able to see the object whenhal o the lens was covered? Why was the

brightness o the image reduced? T/I

(h) Why did you lose hal o the image when you

covered hal o the object? T/I

Apply and Extend(i) List some optical devices that use a lens to

produce a real image. A

(j) Name an optical device that uses a lens to

produce a larger, virtual image. A

(k) Suppose For a converging lens is 23 cm,

and a luminous source is placed at diferent

positions in ront o the lens. Predict the image

characteristics or each position. T/I

64 cm from the lens

40 cm from the lens

10 cm from the lens

paper screen

lens

image

source

Figure 1

13.2 Perform an Activity 555NEL


7/19




[email protected]

Shed a Little Light on the Grade 10 Optics Unit (SNC2D & SNC2P)Time:12:30 PM - 1:30 PMLocation: International C

Are you new to optics? Explore how light interacts with mirrors andlenses. Use ray diagrams to predict image characteristics and test yourpredictions through hands-on inquiry. Computer simulations will be used

to aid conceptual understanding. Support material will be provided.Presenter: Jeff Major

Session Number: 2313

Hands-On: Students are actually allowed to perform science as theyconstruct meaning and acquire understanding.


How do we engage students in


8/19

Minds-On:Activities focus on core concepts, allowing students todevelop thinking processes and encouraging them to question and seek

answers that enhance their knowledge and thereby acquire anunderstanding of the physical universe in which they live.



Authenti c: Students are presented withproblem-solving activities that incorporateauthentic, real-life questions and issues in aformat that encourages collaborative effort,dialogue with informed expert sources, andgeneralization to broader ideas andapplication.



simply "studying the content of science" is not the same as

learning science.knowledge of facts is important, facts must be learned within thecontext of authentic experience




9/19




[email protected]

Rationale for Connecting to Outside World

Scientific literacy is achieved when studentsuse their knowledge

and skills to purposefully plan and take action in the communities

aimed at enhancing personal we llbeing and promoting the betterment

of society and the environment.

Science Education: A Summary of

Research, Theories, and Practice


10/19

The science curriculum has a crucial role to play in teaching them

[students] how to exercise the enormous power of technology

responsibly, carefully and compassionately, and in the interest of all

living creatures.

D. Hodson

Rationale for Connecting to Outside World


11/19

Predict, Explain, Observe, Explain

YES NOJeffSteve Jen Mark MikeAmy Sue


12/19

http://www.uvm.edu/~mfuris/INTRO_PHY SLETS/contents/optics/applications/illustration36_1.html

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=373

Producing images

with two plane

mirrors.


13/19

How Large Does A Mirror Need To Be

To Show Your Entire Body?


14/19

The following diagram illustrates that the minimumlength of a plane mirror required for someone to view

their entire image equals half their height. Note that thetop of the mirror should be placed at eye level.

http://www.batesville.k12.in.us/Physics/PhyNet/Optics/Reflection/Mirror_Size.html


15/19

http://www.nelson.com/onsciencepd/


16/19

http://pages.physics.cornell.edu/courses/p101-102/p102/14/java/concave/index.html

http://pages.physics.cornell.edu/courses/p101-102/p102/14/java/convex/index.html

http://www.phys.ufl.edu/~phy3054/light/lens/applets/convlens/Welcome.html

http://www.phys.ufl.edu/~phy3054/light/mirror/applets/cavemir/Welcome.html

http://www.phys.ufl.edu/~phy3054/light/mirror/applets/convmir/Welcome.html

http://www.phys.ufl.edu/~phy3054/light/lens/applets/divlens/Welcome.html


17/19

http://webphysics.davidson.edu/Applets/optics4/default.html

The Optics

Bench

from

Physlets

does it all:

plane

mirrors,

curved

mirrors,

and lenses.

Where is

the

filament in

a car

headlight

really

located?

The Optics Bench at Physlets lets us answer this:http://webphysics.davidson.edu/Applets/optics4/default.html


18/19

http://www.physics.uoguelph.ca/applets/Intro_physics/kisalev/

Other good optics simulations:

http://www.explorelearning.com/

Gizmos also

has optics

simulations.

http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=39.0

Add it ive

and

subtractivecolour

theory.


19/19

http://javaboutique.internet.com/ColorFinder/

Addit ivecolour

theory:

producing

any colour

Hand Out for Optics

Documents

Transcript of Hand Out for Optics