A few minutes later, and we’re all set up. A beaker of water sits on a tripod, a weighed fragment of the lolly clamped beneath it and, further up the clamp stand, a thermometer held in the water. To one side, the Bunsen burner’s orange flame dances slowly. We worked in silence, Ahmed and I, and it’s clear that he knows his way around the equipment as well as I do. We’re waiting for the rest of the class to get to this stage.

‘Right everyone,’ Mr Walters’ voice booms across the lab. ‘Everyone stop and look at Josh’s table.’

Everyone turns, the flicker of our burner caught in twenty-odd pairs of safety goggles.

‘Look what they’ve done with their thermometer. It’s sat in the middle of the water, not resting at the bottom. Someone please tell me why that’s a good move.’

Silence.

‘Fine. Go on then Josh. Tell us why you did it.’

‘It was Ahmed’s idea, Sir. Not mine.’

Mr Walters seems slightly taken aback.

‘It’s so you take the temperature of the water, rather than the temperature of the glass at the bottom of the beaker, Sir.’ Ahmed’s voice is clear, confident. ‘Otherwise the readings will be artificially high, given that the flame is in direct contact with the Pyrex.’

There’s a short pause before Mr Walters replies. ‘Yes, well. In future, if you can set things up as per the instructions and diagram on the board that would be great, Ahmed. Otherwise you’re going to skew the class’s data. Josh, could you set it right please.’

‘Yes, Sir.’ I adjust the thermometer, dropping it a few centimetres lower in the beaker.

Ahmed fiddles with the Bunsen’s collar, the flame flashing blue, growling, then flicking back orange again. ‘We should be doing this properly,’ he says.

‘Yeah, we need some kind of guard around the flame, right? Otherwise all the heat’s going to spill out the sides.’

‘Exactly.’

‘Gives us something to put in the evaluation I guess.’

We sit in silence again.

‘That was mean, what he did to you just then.’ I readjust the thermometer again, moving it back to the centre of the water.

I feel the tension in Ahmed slacken a little.

‘He’s alright though, Mr Walters. What were your teachers like at home?’ I wonder if ‘home’ is the wrong word. I add, by way of correction, ‘In Halab?’

Ahmed smiles. ‘Hey, you remembered. Not Aleppo. They were fine I guess. Like here. Some want to be your friend, some want to stay as far away as possible. Some good, some bad.’

‘Did they all do the thing where they stand at the classroom door and say hello when you’re coming in?’

‘Sometimes. Some stayed at their desks as we filed in silently. Some met us at the door. There were handshakes as well from some of them.’