According to the Des Moines Register, Peri Sagun had set up a hammock with her 16-year-old sister outside their home in the USA.
They tied one end of the hammock to a tree, and the other end to a 5-foot-tall brick lamppost.
Her older sister climbed into the hammock first, before Peri jumped into it with her.
However the force of Peri’s jump - and the added weight - caused the lamppost to collapse and bricks to fall onto her head.
Peri’s sister ran into the house and screamed for their father, who rushed out to perform CPR on the schoolgirl until an ambulance arrived.
Despite his efforts, Peri was declared dead at Mercy Medical Centre shortly after the accident.
Nancy Dowdle, her head teacher, said: “She was a person who was friendly and happy and always wanted to do her best.”
Another teacher added to KCCI: "She was so rule-bound, I mean you just want a whole class like that that never turns sideways, and that's how she was.”
The school released a statement about Peri, which read: "She dreamed about sunshine, college, and a career as an interior designer.
“The glow from Peri was felt when she entered a room, even to those who didn't know her. But anyone who knew her did and will always love her. Her energy, smile, and caring for those close to her will be what is most remembered.”
Des Moines police do not suspect foul play, and believe the collapsed column was not securely in the ground.
Peri would have graduated from middle school next week as an honours student.
Her school plans to give a diploma to her family, and to honour her at the graduation ceremony.