Encourage your child or teen to experiment with different time lapse photography.
If they are using a smartphone, you could also consider downloading a time-lapse app e.g. Lapse It Pro, PicPac Stop Motion & TimeLapse or Lapse It.
If they are using a camera, some cameras have time lapse settings. If not, then just go with the same spot and same time, or same spot and different times to take your time-lapsed photos.
This might even lead your child or teen onto doing a Stop Motion film next.