# Arithmetic and Stoichiometry

Two summers ago, four men tried to “top” the terrorist attacks on the London Tube but failed, for a reason any science educator can appreciate:

The explosives would have caused carnage on the transport network, but the plot mastermind, Ibrahim, miscalculated the ratios of ingredients when making the bombs, Britain’s Daily Mail newspaper has reported.

The court heard Ibrahim personally bought the bleach and chapati flour used to make the devices in his flat, which was also booby-trapped. Police said the highly volatile triacetone triperoxide, known as “mother of Satan” was used as a detonator.

But Ibrahim, who failed maths at school, got his sums wrong when mixing the recipe, making the bombs — which were packed with nails and screws — harmless.

This story doesn’t make explicit that the “bleach” was actually hair bleach, which the plotters tried to distill to get hydrogen peroxide.

The jury was told that, using two saucepans and a frying pan on the flat’s small cooker, the men set up a seven-day rota involving Ibrahim, Asiedu and Omar to oversee the process of boiling it down to the required concentration. Some was re-bottled with labels suggesting it had reached the required strength. Subsequent test firings by forensic scientists suggested that one reason why the bombs had not fully exploded could have been that the chemical had not been sufficiently reduced.

Triacetone triperoxide (TATP) was also used in the 7 July 2005 attack on the London Underground, and many people speculated that the terrorists responsible for the “War on Liquids” were also trying to make TATP in airplane lavatories.

(Via John Armstrong.)

## 2 thoughts on “Arithmetic and Stoichiometry”

1. If only we could count on the wicked failing their maths more often than the just.

2. manigen says:

Maybe we can. The Glasgow airport attack seems to have been planned and executed by a group with an understanding of the physics of glass and petrol that they picked up from watching Die Hard. They thought the glass would shatter like sugar glass and the petrol would automatically make a huge firebomb.