Up

 

                                                

 

Rogue Physicist.  Free resources for physics education © 2006-2016 Dorian Pascoe.  Email: dorian.pascoe@hotmail.co.uk

Most resources are available under a Creative Commons Licence.  Visit our mirror at www.physicsweb.altervista.org

 

 

 

...wave behaviour...

 

 

 

Objectives:

 

  
 

 

Waves!

  

 

• Know that waves can be reflected and refracted.

 

 

• Be able to recall and use the law of reflection.

 

 

• Be able to describe the circumstances required for refraction to occur.

 

 

• Be able to explain the process of refraction, using scientific ideas about waves.

 

  

 

 

 

 

 

 

 

Task 1 - Starter

 

  
 

 

I know the answer!

 

 

  

 

Find someone who knows:

 

 

1) The seven types of electromagnetic wave, in order.

 

2) Which type of EM wave has the longest wavelength.

 

3) Which type of EM wave has the lowest frequency.

 

4) Which type of EM wave has the highest energy.

 

5) Which type of EM wave travels fastest.

 

 

Your teacher will tell you which questions to discuss.

  

 

 

 

 

 

 

Task 2 - Reflection

 

  
 

 

Lots of waves!

 

 

 

  

 

Waves can be reflected when they hit a shiny surface.  Your teacher will show you a laser being reflected from a plane mirror.

 

 

You will have studied reflection in year 8.  You may already know the law of reflection.  You need to be able to draw accurate diagrams of reflection for your GCSE examination.

 

 

Write the title "Reflection" in your exercise book.  Copy the law of reflection and the diagram below into your book.  You will need to draw the diagram carefully, using a sharp pencil and a ruler.

 

The law of reflection:

"The angle of reflection is always equal to (the same as) the angle of incidence"

 

 

 

 

When you have completed your diagram, draw a second diagram for light reflected with a greater angle of incidence.

 

 

  

 

 

 

 

 

 

 

 

Task 3 - Images formed in a mirror

 

  
 

 

My brain uses electrical waves.

 

 

  

 

When we look in a mirror, it looks as if there is an image inside the mirror - but of course, it is not really there!  We call it a virtual image.  The image formed is upright, but appears to have been flipped horizontally, as if right and left have been reversed.  We say the image is laterally inverted.

The image formed in a mirror is virtual, upright and laterally inverted.

Teacher note: there is a copy of the diagram available here, if required.

 

  

 

 

 

 

 

 

 

Task 4 - Investigating refraction

 

  
 

 

 

 

  

 

Light, and other waves, can also change direction when they encounter a change in medium.  This is known as refraction.

 

Follow the instructions on this sheet to investigate how the path of the light changes as it travels through a glass block.

 

 

 

 

When you have completed the task complete the diagram on this sheet, and fill in the missing words in the text.

 

 

 

  

 

 

 

 

 

 

 

Homework

 

  
 

 

Let's catch some waves!

 

 

 

 

  

 

1) Complete the path of the reflected ray in each of these diagrams.

 

 

Click the image below to download this task as a word document.

• Measure angles carefully, using a protractor.

• Label your diagram to show the normal.

• Label the angle of incidence.

• Label the angle of reflection.

• Draw arrows to show the direction of the incident and reflected rays.

 

 

2) Find out how refraction is used in a lens, and three examples of devices which use lenses.