| Light travels in straight lines. | A pinhole camera made from a cardboard box has a lighted candle placed in front of it. |
 |
An inverted image on the screen shows the light rays travel from the candle in straight lines. | ||||
| Motor car headlamps give straight beams of light. |
 |
||||||
| Light travels very fast indeed. | Light travels much more quickly than sound. |
 |
Think of a thunder storm. You see the flash of lightning before you hear the crash of thunder. | ||||
|
The speed of light is about 300 000 km per second. |
The currently accepted value is 299 792 km/s based on several measurements. |
Sometimes we write the speed as 300 000 000 m/s |
|||||
| Light doesn't usually go round things. | If something is in the way of light like this: |
 |
Then you get a shadow. |
||||
about shadows.
