Science Buddies: "Ask an Expert"

I have a student who wishes to build a circuit that detects rain water and shuts off a sprinkler system. This is more of an engineering project and we would like ideas on how to convert it to a scientific method process. Any suggestions?

Hello. Designing and building a device to solve a problem follows the engineering design process. It is different from the scientific method process, and you can read more about it here.

https://www.sciencebuddies.org/engineer ... ignprocess

This is an excellent science fair project and sounds very interesting. Are there other reasons why you want to change it to a scientific method process? Read through the process and write back if you have any questions.

Good luck!

Hi,

Do you know if your student got the idea from this project on our site?

https://www.sciencebuddies.org/science- ... p066.shtml

That project gives a simple design for a circuit that will detect whether a sponge is wet or dry (and just lights up an LED as an indicator - it does not turn a real sprinkler system on or off, which is much more complicated). I can think of a couple different examples of how you could do a scientific method project using that device, by changing some independent variable:

- The circuit has a handful of resistors in it - what happens if you change one of the resistor values?
- The project has you soak a sponge directly in tap water to get it wet. What happens if you try to simulate "rain" better (like with a watering can) - how long does it take for the sponge to get wet enough to trigger the circuit? How long does it take the sponge to dry out?