This is a writing exercise for the student, and answers will vary.
Work Step by Step
Sample answer: Hi Grandpa, the next time a lightning storm develops, you probably already know not to take shelter near tall objects such as trees or flagpoles. What you may not know is that you'd be pretty safe inside your car, whose metal surface acts as a "Faraday cage". Inside of a conductor, the electric field remains zero because charges on the surface re-arrange themselves to make it so. Grandma's Pontiac Fiero has plastic body panels, so you might want to avoid taking shelter in that.