Suitable For
Grade 7
Difficulty
3
Time Required
<1 Week
Supervision
Advised
What’s it about?
Many electrical devices are used as early warning systems such as burglar alarms, electric fencing systems and many more. Don’t you think it will be useful to have an early warning system for rain to warn you to close the windows and bring in the clothes from the clothesline? In the following science experiment you will build a device that can detect rain as soon as the first drops start to fall:
Topics covered
Electrical current, Buzzer
What will I need?
- 9-VOLT BATTERY
- PLASTIC COATED COPPER WIRE
- 9-VOLT BUZZER / BELL
- CLOTHESPIN
- EFFERVESCENT TABLETS
- WIRE CUTTERS
- RUBBER CEMENT
Procedure (Method)
Unfortunately, this section is only available in the e-book version of the project.
How does it work?
Unfortunately, this section is only available in the e-book version of the project.
The power or ‘electrical energy’ stored in a battery can only be released and allowed to flow when a complete circuit is made out of wires or other ‘conductors’ that conduct electricity. In the above experiment, the electrical circuit is not complete until the prongs of the clothes pins with the wires wrapped around it are pressed together.
When the rain drops degenerate and melt the effervescent tablet, the prongs with the wire contact pieces are pressed together, making a circular path between the battery and the bell. The current flows in a complete ‘loop’ from the battery through the ‘rain detector’ on the window sill to the buzzer and battery in your room. When the circuit is complete and the current is flowing, the buzzer sounds to warn you of the rain that started to fall!
Like the sound of it?
Why not check out the full worksheet in one of our popular e-books?
This particular science project can be found in any of the following Experiland e-books:
Experiland e-books contain detailed steps, including illustrations, to complete the science projects from start to finish.
