A health and safety investigation has been launched after two pupils fell through the window of a school bus.
The boys, aged 14 and 15, were travelling from Dayncourt School in Radcliffe on Trent to Cotgrave last Friday when the accident happened.
The bus - operated by Premiere Travel - took a left-hand turn around a corner in Stragglethorpe. The boys fell through a window near the back seat.
The 15-year-old was taken to hospital by ambulance with minor injuries.
Premiere Travel said the bus driver had told pupils not to move around on the back seat of the single-decker bus during the journey.
A spokesman said: "Something like this is extremely rare. A lot of school buses can be rowdy but other ones are fine and we have no problems.
"Windows don't fall out of buses when we're taking commuters home...but they do fall out when there's seven or eight kids all putting pressure against a window that's held into a bus body with rubber."
Nottinghamshire Police said the bus was examined and the case has been passed to the Health and Safety Executive. No-one has been charged in relation to the incident.