I feel that since this project requires lasers I should give the warning posted on all laser teasers...
Avoid Direct Eye Exposure
That means don't shine it in anyone's eye (including a cat's)
You will need a laser teaser, water bottles ( I will show some arrangements for up to seven), and a cat.
All you need to do is set the water bottles up in any patteren ( I have included some ideas) and shine the laser through them and move the beam around. this creates a "dancing" display that your cats will watch with great content.
Since I am entering this in the "Make-To-Learn Youth Contest" so here are my answers...
What Did You Make?
I made a cat toy that can be changed just by moving water bottles around. It works by taking the light from the beam and scattering it, making a pattern that cats will chase after. No tools were involved and I only needed some water bottles, a laser beam and a cat.
How Did You Make It?
As I said before, I was playing with a laser teaser and I shined it at a water bottle and decided to make a "toy" on my own. My plan didn't change because it was very straight forward, organize water bottles to make a cool design for my cats.
Where Did You Make It?
I made it a my house one day. There is no specific activity that this fits in with. I just decided to make something for my cats.
What Did You Learn?
My biggest challenge was getting my cat comfortable with the camera so I could take pictures for instructables. My biggest surprise was just how a little bit of light and water can become a toy for a cat. I am proudest of idea to build a better cat teaser. And finally, if I had to do it again I would take off the wrappers of the bottles to let more light through.