- Light is needed before we can see anything (See reflections)
- Light is given out from a luminous source eg the Sun or a projector lamp.
Remember that it is dangerous to look straight at the Sun because the light is too bright.
If you wish to look towards the Sun (eg during a Solar Eclipse) then it is very important that you look through a special dark filter (sun glasses are NOT dark enough)
Luminous sources in a room
The Moon does NOT give out light
We see the moon because light from the sun is reflected from the Moon towards the Earth.
Light travels in straight lines which can be drawn as a straight line with an arrow in the middle.
In order to see anything light has to be reflected off of it and enter our eye.
Rays of light will reflect of a smooth surface like a mirror.
When they do the angle that they leave the mirror will be the same as the angle that they hit the mirror
Using reflection 1
Using reflection 2
An opaque object (like a stick) forms the best shadow
A translucent object forms a slight shadow
A transparent object may not form any shadow
In this diagram light is shining on a white screen.
An orange ball is blocking the light, forming a shadow on the screen.
This experiment shows us that light travels in straight lines.
In the experiment above there are three things we can change:
We can move the ball towards the screen
We can move the light towards the ball
or we can move the screen towards the ball
It is important that we change only one of these at a time or it will not be a fair test
If the ball moves towards the screen the shadow will get Larger or smaller?
If the ball moves nearer to the light the shadow will get Larger or smaller?
Name the main source of light we use to see things outside ? Answer
If a light bulb is moved nearer to an object, the shadow from the object would get larger or smaller ? Answer
The Moon is a luminous object and gives out light. True or False? Answer
A solid object that blocks out light is transparent, translucent or opaque? Answer
Complete this sentence: Light always travels in ………….. Answer
When light is blocked it formes a ………………………. ? Answer