A pressure cooker bomb

- Cooker uses pressure and steam to cook food faster at a higher temperature

- Air-tight lid keeps steam in pot

- Pressure builds in pot allowing temperature to rise above boiling point of 212 F (100 C)

- TNT or other explosives put in 6.3- qt. (6 liter) pressure cooker along with metal shards, nails, ball bearings to inflict maximum injury

- Blasting cap attached to the top of the cooker

- Can be detonated with a digital watch, cell phone, garage door opener

(1) When primary charge explodes, gases heat up, expand rapidly under pressure
(2) Expansion creates shock waves travelling outward
(3) Blast fragments cooker, sends pieces of shrapnel outwards at high speeds

Heat from explosion causes fire

- Pressure cooker bombs used in India, Afghanistan, Pakistan, Nepal and 2010 Times Square bombing attempt