Science Buddies: "Ask an Expert"

Hey,
i am having some trouble filling out the scientific method for my project, for example,
how do i explain what the control variable is? the method doesn't seem to apply for creating new products.
Thanks for any help,
Dinesh

The way you'd probably best apply the scientific method to project like the one in the title would be to create your stylus and then test its effectiveness on a couple of different brands of touchscreen if you can get ahold of them (or vary parameters, like the diameter of the tip, and see what the most effective size is).

Luckily, I can help if you run into problems... I work at a major vendor of capacitive touchscreens .