Asked by: Richard O’Neill, Glasgow
In 2011, a 10-year-old girl called Erin Moran was struck by lightning while sitting at the window of her bedroom in Merthyr Tydfil.
Glass is a good insulator, so it is very unlikely that a window pane would ever be struck directly. But a lightning strike on the roof of a house will travel down through the building through the most conductive route available.
The sudden heating of a metal window frame might cause enough expansion to crack the window.
The accompanying thunder is caused by the shock wave from the channel of superheated plasma that the lightning bolt creates between the ground and the cloud. This could also shatter a window if it was close enough.
In Erin’s case, the bolt struck the apex of the attic window, cracked the glass, jumped to her shoulder, passed through her body and out of her foot to the floor. She was left with a snowflake-shaped scar on her arm, but was otherwise unhurt.
Subscribe to BBC Focus magazine for fascinating new Q&As every month and follow @sciencefocusQA on Twitter for your daily dose of fun science facts.