# Reflection

OP38 investigate the reflection of light by plane mirrors, and illustrate this using ray diagrams; demonstrate and explain the operation of a simple periscope

The following link shows you what you can prove in the following investigation, well worth a look

http://www.acoustics.salford.ac.uk/feschools/waves/reflect.htm#reflect

Reflection occurs at object that have a smooth surface. Often these surfaces are made of glass or metal.

Lateral Inversion

Title

OP38 To Investigate reflection

Apparatus

A mirror

4 pins

A page

A pen

Method

1. Place a page on some thick card or polystyrene
2. Set up a Mirror to stand upright on a page,
3. Trace the outline of the mirror on to the page
4. Place 2 pins so they make a line to the mirror at an angle.
5. Make sure this line is at an angle to the mirror
6. Look through the 1st pin as so the other pin is blocked from view

Now look into the mirror, and witness the reflection of the 2nd pin obstructing your view of the 1st pin

Take another pin and place it in the page along a line that obstructs the view of the other two pins in the relection of the mirror

Do this again so all other pins maybe blocked from view in one line.

Remove the pins and the mirror, and join up the dots using a ruler, continue the lines Through to the other side of the mirror.

Draw in the normal (a line at right angles to the mirror, that also starts at the point the other 2 lines cross.

Safety Concerns

Results / Observations

Your drawing of the lines (and labelled angles) is your results in this investigation

Maths

examine the angles

Conclusions

What can you say about the angles of each ray

The angle of the ray going into the mirror is equal to the angle coming out of the mirror

http://www.freezeray.com/flashFiles/Reflection1.htm

Periscope

Title

To build a periscope

Apparatus

2 prisms (90o) or mirrors, a poster tube, Scissors or knife, sellotape

Method

1. Cut 2 holes, 1 at either end but on opposite sides of the tube
2. place mirrors or prisms in the tube opposite the holes.
3. Ensure the mirrors or prisms are at 45o to the view hole.
4. Seal both ends.
5. Look through it.

Safety Concerns

Get an Adult to cut the holes

Results / Observations

.................

Conclusions

A periscope .....