"I didn't know you were born in black and white times, Mr Eddison," Amy says after we have established that the fat, blurry baby in the battered photograph is me aged four months. I am grinning (or it could be wind) out of a 1950s Silver Cross pram. The children think the pram looks more ridiculous than the baby until I point out that if it was still around today I could expect to get a small fortune for it on eBay. Ryan, who is always on the lookout for the chance to make several fast bucks, wants to know where it is now.
"Is it in a museum, Mr Eddison?" asks Amy, which is where I suspect the children think I should be.
"I doubt it," I reply. "The last time I saw those wheels they were an integral part of a soapbox cart."
"What's a soapbox cart?" Ryan asks. I sigh wearily and click the next slide up.
On screen now is a full colour photograph of a beautiful baby girl. She has a familiar grin, no teeth and a big pink bow on the top of her bald head. "Now who could this be?" I ask. Everybody points at Chloe but I am not convinced. "Wait a minute, I know. It's you isn't it, Ryan?" I say and everyone falls about laughing.
The only child who hasn't brought in a baby photo is Regan. She says she will bring one in tomorrow, only she won't because she doesn't have one. If there were any pictures taken in those first few months of her life they somehow got lost in transit. A lot of things can go missing on that short journey from birth to 5. Especially when the route winds through various forms of neglect and several short-term foster carers.
In 1839, Robert Cornelius produced a daguerreotype of himself. It is one of the earliest photographic portraits and it changed things for ever. So astounded was the world by this development that cultures not grounded in a scientific method didn't trust it. Some believed the camera could steal the soul and hold it prisoner. The odd thing is that they were right.
While flicking through old albums the other day I found a me I don't remember being. A child whose innocence contains the blueprint for all my deficiencies and a genetic code preset to deliver haemorrhoids and arthritis. Gathered around him are the architects of who he would become.
There is something reassuring about family albums. The fact that they chart our existence from chubby-cheeked cherub to wrinkled old git gives us a unique sense of who we are and where we came from. It is vaguely magical to think that in this collection of old images I am bound to those who went before me and to those who came after.
Two days later, Regan brings in her baby photograph and shows it round. "Don't say anything but it's an old one of me," whispers her adoptive mum. "Do you think the children will be able to tell it's not her?"
"I doubt it," I reply. "They're more interested in the pram." It's a circa 1982 Silver Cross and would fetch a small fortune on eBay.
Steve Eddison teaches children aged 7-11 at Arbourthorne Community Primary School in Sheffield, England.