A hapless teacher caused terrified children to run for cover after be bungled a chemistry experiment – with explosive results.
Egyptian teacher Ahmed Gabr, 38, was trying to demonstrate how to how to produce a mild reaction by producing oxyhydrogen, or bang gas as it is also known.
But he apparently messed up the quantities and sent schoolchildren screaming from the classroom when the tumbler he was using exploded, showering the room with sparks, flying glass and boiling chemicals.
In a video of the accident, the explosion is so huge, some of the terrified children can be heard praying as they scramble to get out of the classroom while others shout out in terror.
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Angry parents flooded the school with complaints as their children came home with chemical splattered clothing.
The video has now gone viral – and has made the teacher a laughing stock.
One - mother Asim Kanika, 36, - said: "That man is a fool. Its amazing nobody lost an eye with all that flying glass."
She added: "He's very lucky that none of the children were really hurt, just very scared and shaken up."
One viewer of the footage on YouTube joked: "A lesson the kids won't forget in a hurry."