- Not yet done - Coming Term 2 2018

REVISION: With reference to the ST3T1 ELECTRICITY wiki page, What do you think is the difference between 'Light' and 'Electricity'?

A student:

Electrical circuits

Energy from a variety of sources

Light from a source

• Source: NESA Science K-10 Syllabus - Stage 3 2018

FLIPPED CLASSROOM is a form of blended learning in which students learn content online by watching video lectures, usually at home. What used to be called 'homework' is now done in class with teachers and students collaborating, discussing and solving questions.

In a 'flipped' project, teacher interaction with students is more personalised. The emphasis is on guidance and mutual discovery rather than lecturing. More information and resources are available for teachers in the WPS Teacher WIKI.

The starting point for this particular 'flipped' activity is an on-line science QUIZ:

Have you ever thrown a rubber ball at something?

If you have, you know that when the ball hits most things, it bounces off them.

Like a rubber ball, light bounces off most things it hits - Light is made up of lots of things that bounce.

1. When light falls on something, mostly, it is like a hand-full of rubber balls being thrown - not just one ball.
2. When light travels to something opaque, some of this light stops there - BUT, some of this light bounces off.
3. When light travels to something translucent or transparent, most of the light passes through - BUT, some of this light bounces off.
4. When light bounces off things and travels to your eyes, this information is passed to your brain and you are able to see. ¹⁾

When light bounces off of things, scientists call this reflection

To explain how light travels and bounces off of things, scientists use 'ray diagrams'.

A ray diagram is a drawing with arrows that shows where the light is coming from, what it is hitting, and where it travels after it bounces off of something - detailed science resources from lightandmatter - Read more...

This experiment will show what happens when light shines through a small hole onto a wall.

• You will need two pieces of card - each about 70mm or larger and something to make small , round hole in the centre of each card.
• Make a guess (your 'hypothesis') about what you will see on the wall when you hold the cards close to the wall so that light can pass through the hole (write down what you think you will see)?

• Make a small hole (the size of a 5cent piece or smaller) in a piece of card
• Hold the card close to a wall so that the card makes a shadow on the wall and light shining through the hole makes a bright spot on the wall.

• First try the card with the smaller hole and write down what you see.

• Repeat the experiment using using the card whose hole is twice as large as the first card.
• What do you see (write down what you see)?
• Also, write down any differences (you may not notice any), between using a card with a small or a larger hole?

Draw a ray diagram showing how the light travels from a torch, through a small hole and onto a wall.

Below the ray diagram, draw what you saw for each size hole and add labels to show what you saw.

Q 1. How can you find out where the light that falls on the wall is coming from?

• Write down what you think

Q 2. Can you think of an experiment to show that light bounces off something in the same way that a ball would bounce off the same thing?

• Write down what you think

Is there any difference between what you see on the wall when you compare when light shines through the small hole compared with when light shines through the larger hole (write down what you think)?

• IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY: Viewpure Light from the sun

Video 2. Opaque Objects & Shadows

• IF YOUTUBE FAILS, TRY VIEWPURE:Opaque Objects & Shadows

If you have time, cut out your own animal shapes using cardboard and find a dim room. Use a torch to make shadows of your cardboard cut-outs and see what happens to the shadows when you move things around. If you have a dark room and a lamp, you can even put on a shadow play using your hands, or make your own shadow puppets

If you were to turn off the room lights for a moment and then cover all the windows with black paper so that absolutely no light can enter, do you think that you would still be able to see anything in the room?

• There would still be objects present that could normally be seen.
• Your eyes would still be capable of detecting light from those objects.
• Your brain would still be capable of making sense of the information sent to it.
• But there would be no light! The room and everything in it would look black.

And so, what do we see when we see black?

When we see 'black', we are not seeing a colour, it is simply the absence of light - Do you 'see' what that means?!

To put it another way: When a room full of objects (or a table, a shirt, a chair or a sky) looks black, then it is because those objects are not generating and/or reflecting light into your eyes.

So, without light, do you think you would you be able to see anything?

Source: ²⁾

• Light waves and colour
• Reflection and the ray model of light Reflection interactive
• Refraction and the ray model of light Refraction interactive

• IF UNABLE TO ACCESS YOUTUBE VIDEO (requires Flash) TRY: Viewpure Refraction & Colours Explained

CLASSROOM ACTIVITY: Complete a 'marching soldier analogy' experiment

• Link to OLD Electricity Quiz
• Niel Turock - Light & The Origin of Quantum Mechanics

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