We can explain how convex and concave lenses work.

Slides:



Advertisements
Similar presentations
Ray Diagrams.
Advertisements

(c) McGraw Hill Ryerson Using Lenses to Form Images A lens is a piece of transparent material that can bend, or refract, light rays in useful.
All visible objects emit or reflect light rays in all directions.
Light = straight path An atom: emits light when an electron moves from a high to a low energy level. absorbs energy as its electrons move from a low.
LENSES. Lenses Lenses REFRACT light and are usually used to form IMAGES 2 types convexconcave bi-convex plano-concave plano-convex bi-concave.
Welcome to Optics JEOPARDY PHysics Final Jeopardy Question Reflection Mirrors 100 Lens refraction Special topics.
Chapter 16.3 – Reflection and Color
Refraction (bending light) Refraction is when light bends as it passes from one medium into another. When light traveling through air passes into the glass.
Convex and Concave Lenses
Thin Lenses.
Compare and Contrast convex and concave Lenses (order jumbled) Convex lenses are wider in the middle than they are at the edges and concave lenses are.
Textbook Chp 12.4 Pg 237 to 247.  Converging and Diverging Lenses  Focal Length of a Converging Lens  Ray Diagrams for Converging Lens.
21/04/2017 KS3 Light.
A. can be focused on a screen. B. can be projected on a wall.
LIGHT CH. 18. What is Light? Light is an electromagnetic wave that travels through space requiring no medium.
1.What is the fundamental difference between a real image and a virtual one? 2.Parallel light rays are focused on the focal point of a concave mirror.
Curved Lenses SNC2P – Optics. Lenses Lenses are thin pieces of glass or plastic that have at least one curved side. There are two basic types of lenses:
13-3 and Notes Mirrors. Concave Mirror – An inwardly curved, mirrored surface that is a portion of a sphere and that converges incoming light. Concave.
Predicting Images in Convex and Concave Lenses. When the object is located at twice the focal length (2F)
SEEING THROUGH A LENS.  We see the world through lenses.  Eye glasses = lenses. Contact lenses = lenses.  Magnifying glasses = lenses. Microscopes.
Ray Diagrams Noadswood Science, 2013.
Copyright © 2010 McGraw-Hill Ryerson Ltd. What are lenses and what are some of their applications? Topic4.6 (Pages )
Converging Lenses Section 4.6 Lesson 13. Lenses A lens is a thin transparent piece of glass or plastic that has at least one curved side –The sides can.
CONVERGING LENSES. Lenses Lenses REFRACT light and are usually used to form IMAGES 2 types convexconcave bi-convex plano-concave plano-convex bi-concave.
HOW DO LENS’S HELP US SEE?. Aims  Revisit the idea that light can be bent (refracted).  Know how light bends in a convex (converging lens) and a concave.
LENSES AND THE FORMATION OF IMAGES. Lenses We see the world through lenses… Eye glasses = lenses Contacts = lenses Magnifying glasses = lenses Microscopes.
Lenses Convex lenses converge rays of light. Parallel rays converge a fixed distance away from the lens. This is known as the focal length.
Refraction The bending of waves as they pass from one medium to another.
Image Formation. Flat Mirrors  p is called the object distance  q is called the image distance  θ 1 = θ 2 Virtual Image: formed when light rays do.
Light In this unit: 1)Properties of light 2)Reflection 3)Colours 4)Refraction.
Images Formed by Lenses Ray Diagrams for Lenses Ray diagrams can be used to predict characteristics of images using 3 rays, just like for concave.
 A lens is a transparent object with at least one curved side that causes light to refract  Like mirrors, lenses have surfaces that are described as.
LENSES Write down anything like this!.  Different types of lenses play an important part in our lives. They are used in cameras, telescopes, microscopes,
Mirrors.
It’s amazing!…Can you imagine life without it?
Lenses Lenses _______ light and are usually used to form ________ There are two types: In practice, light is refracted at both surfaces of the lens but.
Refraction & Lenses Sections 11.7 and 11.8.
Ray Box Lab Debrief Tahoma Jr. High 8 th Grade Science Maple Valley, WA.
AP Physics Mr. Jean February 10 th, The plan: Diverging Mirrors Lenses.
SEEING THROUGH A LENS.  We see the world through lenses.  Eye glasses = lenses. Contact lenses = lenses.  Magnifying glasses = lenses. Microscopes.
Mirrors. Types of mirror There are two types of mirror Plane (flat) Curved Concave (curves in) Convex (curves out)
Optics. dispersion Shorter wavelengths refract more than longer wavelengths – Violet light bent the most Color.
Mav Mark What are forms of the electromagnetic spectrum?
Lights, Mirrors, and Lenses Light is another type of wave that carries energy. A light ray is a narrow beam of light that travels in a straight line. Light.
Revision Revision of ray diagrams Quiz How does the eye work video:
Refraction. Refraction of Light When light waves pass from one medium to the next, its speed changes, causing it to bend. Going from lower to higher index.
Light and Optics Part Three: Optics and Reflection.
Lenses Converging and Diverging Lenses.
Locating the image for lenses
While you are watching the video think about why this is happening.
Ch. 30 Lenses.
Answer the “4 big questions”.
Notes 23.3: Lenses and Images
Thin Lenses 1/p + 1/q = 1/f 1/f = (n -1) (1/R1 - 1/R2)
Geometric Optics.
What Happens When… Light is transmitted through a glass shaped like a triangle? Light is transmitted straight toward a glass shaped like a square?
Introduction to Lenses
Lenses and Ray Diagrams.
14-2 Thin lenses.
5.3 Using Lenses to Form Images
5.3 Using Lenses to Form Images
LENSES A lens is defined as - A ground or molded piece of glass, plastic, or other transparent material with opposite surfaces either or both of which.
Lenses.
5.3 Using Lenses to Form Images
5.3: Using Lenses to Form Images
Using Lenses to Form Images
5.3: Using Lenses to Form Images
(c) McGraw Hill Ryerson 2007
5.3 Using Lenses to Form Images
Presentation transcript:

We can explain how convex and concave lenses work. We know when the first lenses were made and what the simplest lens in the world is.

Recap Answer these questions on your white board: What colour do you get: - if you shine red and green lights at a white surface? - if you shine blue and red lights at a white surface? - if you mix cyan and magenta inks? How do you make these colours from a printer? red? green? What colour will they look, - if you look at blue trousers in red light? if you look at blue trousers in magenta light? if you look at yellow trousers in green light?

Quick quiz 1. Name three things that we use lenses for. Microscopes, glasses, telescopes, magnifying glasses 2. How old is the oldest lens that we have? About 2700 years old 3. How old is the oldest picture we have which shows a lens? About 2800 years old (ancient Egypt) 4. What is the simplest magnifying glass there is? A drop of water. 5. When did people first wear glasses? In the 13th century. 6. What property of light do lenses use? Refraction. 7. What kind of lenses do you know? Convex, concave.

Make notes We use lenses in microscopes, telescopes, glasses and magnifying glasses. The oldest lenses are over 2800 years old. They were made our of a natural crystal. People have worn glasses since the 13th Century. Lenses use the phenomenon of refraction. They refract the light to give an image. There are two main forms of lens:

What‘s this? It‘s the Nimrud lens. When was it made? About 750 BC. What did they use it for? Maybe to start fires.

Refraction What do you remember? http://www.neok12.com/php/watch.php?v=zX0a6a7b01014b4e727a7f7b&t=Light-Optics  

Do the questions So what happens when light hits and goes through these lenses? Draw it on the board.

Now do the experiment Set up the ray box so that you can see three or five rays of light. Make sure that the middle ray goes straight through the middle of the lens. It should pass straight through. Draw on your diagrams what happens to the light when it goes through the different lenses. Draw round the lenses and put dots on the rays of light before and after the lenses. Do the rays of light meet anywhere?

Convex FOCUS F PARALLEL rays from distant object focal length axis F PARALLEL rays from distant object focal length Convex lenses bring the rays together (‘converge’) at a focus. Convex lenses are CONVERGING LENSES

Concave PARALLEL rays from distant object F F FOCUS (‘Virtual’) focal length Concave lenses spread the rays out (‘diverge’). The rays seem to come from a ‘virtual focus’ on the other side. Concave lenses are DIVERGING LENSES Jump back to ray diagrams Next

Recap. What is a convex lens? Where do parallel rays meet? Can you think of any uses of convex lenses? What is a concave lens? Can you think of any uses of concave lenses?