Question

What physical properties of an explosive compound could be used to detect a bomb before it detonates?

Answer 1

1- Smell - Dogs are trained to detect explosive by there scent . This is the most traditional way. Nowadays honeybees are also known to have better sensitivity than dogs towards smell.

2- Density - X-rays are used to find density of many materials. Explosives inside bags are detected using X-rays by finding density of different materials inside bag.

3-Ionization - Ion mobility spectrometer is used to collect data of mass to charge ratio for different compounds. Same technique can also be applied to exolosive. This is similar to mass spectroscopy technique but under atmospheric pressure.

4-Reflectivity -  Explosive material reflect visible, infrared and ultraviolet radiations and the amount reflected is used to ensure existence of explosive and its amount.

5- Gamma radiation decay - When an explosive material is bombarded with neutrons gamma radiations decays from the explosive material which is used to detect explosive in suspected area.