This is my son with his adopted grandfather, aka my new father-in-law. Josh has lost both grandfathers, and fil has taken on the job beautifully. Josh had a kit in his stocking for making a salt-water powered car, so the pair of them set to and made it, and made sure the chemical reaction at the end, worked enough to drive the car. Dh slept throughout, and just woke to watch the car zipping around the hall. I love how the pair of them are working on this together so intently!