Taking a group of rowdy inner-city eight-year-olds to the Natural History Museum was a daunting task for a trainee teacher. Our journey there was an event: two hair-raising trips on London's Underground with commuters to bother.
Little did I know, as I led my mob into the museum behind blazer-wearing, politely-spoken little angels, that the appeal of a dinosaur skeleton would prove too much for one of my party.
As quick as I could say: "Oh look, children, a stegosaurus!" one of them had scaled the million-year-old exhibit and was riding bareback on the tail for all to see.
Avoiding the disapproving looks from my other teachers, I lifted the offender off and promptly took him and his entourage to the Earth Zone.
In the hydro-electric section my motley crew worked the water pumps until little beads of sweat began to coat their foreheads.
You could experience a simulated earthquake, the build-up to which stirred great excitement among the children. We passed relentless video footage of earthquakes in action and even a car submerged in lava, which drew several gasps. Then, as we stood in a replica Kobe shop, the jovial mood of the youngsters turned ominous.
The lights flickered and as the rocking motions began, my children's survival instincts abandoned them and in unison they proclaimed: "Shit! We're all going to die."
My first science lesson with Year 1. Never my strongest subject, I struggled for ages with the concept of explaining forces. Quite how I thought placing a variety of toys on each table would encourage five-year-olds to ponder this is beyond me now.
I read and re-read the books meticulously prior to the lesson, which was to be observed by the head, yet I still couldn't shake the nagging feeling of doubt that kept creeping into my mind.
As soon as the lesson began, there was chaos. My plan was to circulate around the tables, posing open-ended questions to elicit learning.
What actually happened was the classroom equivalent of the assault on Omaha beach. Balls were whizzing through the air, some precariously close to bringing down the washing line.
Kamikaze dolls were sent into freefall to "determine gravity", while outside, motorcross stunts were being performed on tricycles behind my back with blatant disregard for the risk assessment.
A rope I had laid down for a tug of war was being strung around the waist of one girl, pulled by another shouting, "horsey!"
As I surveyed the carnage I felt a small tug on my sleeve. "Miss Tyrrel, please may I go to the toilet?" inquired a serious-looking young chap.
"Of course, but quickly," I replied. He pondered this for a minute before adding: "I think I should warn you, I might be a long time with this poo."
Hannah Tyrrel is a teacher in Middlesex