Shadow
Objectives
Pupils will be able to
* state that shadow is formed when light is completely or partially blocked by an object.
* infer that an object may cast shadows of different shapes and sizes.
Introduction
What is a Shadow?
Activity 1 - (10 minutes)
Go through your textbook (pages 58 - 61) for some background knowledge of what a shadow is and how it is cast.
Click on the link below to read about the facts about shadow
http://www.suzy.co.nz/SuzysWorld/Factpage.asp?FactSheet=123
Extra Information
Below is a more elaborate explanation but this is optional. It's alright if you do not really understand what the page is trying to say.
http://en.wikipedia.org/wiki/Shadow
Exploring shadows
Activity 2 - (10 minutes)
Shadow in Art
Shadows create fascinating pictures on their own, and they also are beautiful when paired with their parent object.
Look at the pictures taken by some photographers who are particularly interested in focusing shadows as their subject.
http://www.betterphoto.com/gallery/dynoGall2.asp?catID=269
Virtual Shadow (Optional)
Click on the link below and you can explore with the shapes, size and colour of the shadow.
There are two light sources, one red and the other is green. You can shift the object to see how the shadows change. You can also bring the two light source together and see what happens.
http://www.learner.org/teacherslab/science/light/color/shadows/index.html
For explanations click here
http://www.learner.org/teacherslab/science/light/color/shadows/coloredshadowsbackground.html
Experiment Videos
Activity 3 (15 minutes)
Shape Shifting Shadow
Watch the video below and answer the questions below.
1. What happens when the torch
a. is move towards the battery?
b. is move away from the battery?
Casting Multiple Shadows
You learned that a shadow is cast when light is being blocked by an object that does not allow light to pass through.
Watch the video below and see how we change the direction of the shadow and cast more than 1 shadow. Answer the questions below when you have finished watching the video.
1. What happens to the shadow when the position of the light source is shifted?
2. How can we cast two or more shadows with one object?
Recap Activity 4 (5 minutes)
Check your understanding of this lesson with your partner by answering the questions below.
1. What is a shadow?
2. How do you make a shadow of an object shorter?
3. When is the shadow of an object shortest?
Note: All answers will be posted under the comments section next week (26/9/07)
