Mystery #3Tier 2-3electricity
How does a glass touchscreen know exactly where your finger taps?
A touchscreen is just a smooth, flat sheet of glass, yet the instant your finger lands on it, it knows exactly where you tapped. Poke it with a plastic pen and often nothing happens at all. How does a plain slab of glass tell where you touched, and even what touched it?
Your guess
What do you reckon lets the screen feel your finger but ignore a plastic pen?
There's no single magic word to type, have a go in your own words, then reveal the answer to see how close you got.
Make a guess to unlock the hints and the answer.