Question 11
We use electric lights in our schools and homes. The electric light bulb was invented by Thomas Edison. Edison tried 1600 different materials inside the electric light bulb to make it work. Some materials were bright and others were not. Some materials lasted longer than others.
Look at the table and answer the question.
| Material | Bright? | How long did it last? |
|:-|:-:|:-|
| Cotton | yes | 8 seconds |
| Wool | no | 0 seconds |
| Hair | yes | 2 seconds |
| Coconut string | yes | 12 seconds |
| Wood | yes | 8 seconds |
| Paper | yes | 6 seconds |
Why are electric lights so good to use?
Look at the table and answer the question.
| Material | Bright? | How long did it last? |
|:-|:-:|:-|
| Cotton | yes | 8 seconds |
| Wool | no | 0 seconds |
| Hair | yes | 2 seconds |
| Coconut string | yes | 12 seconds |
| Wood | yes | 8 seconds |
| Paper | yes | 6 seconds |
Why are electric lights so good to use?
