ww2 + great power race for nukes

radioactivity coined by

marie curie 1898

in 1914,

nukes sci-fi by leo szilard

where it all began

einstein sends letter to fdr concerned about atomic bomb, worried germans will get it first

in 1942

manhattan project formed

2 types of atomic bomb

uranium (u-235) little boy & plutonium (pu-239) fatman

stages of nuke production

1. get fissile material (U-235, Pu-239)

2. learn how to blow it up

3. build delivery system

making fissile material

uranium has to be enriched, turn ore into gas and spin to increase concentration (centrifuge); plutonium must be made in reactor and separated in reprocessing facility

2 types of weapon design

gun type and implosion type

gun type nuke

fissile material kept in 2 subcritical separate masses (uranium only)

implosion type nuke

carefully arranged sequence of explosives focused onto exploding the fissile core 

july 1945

first trinity test

nuclear explosion unit of measurement

kilotons (1k tons) or megatons (1M tons)

nuclear explosion effect

expands rapidly outward, fireball, leads to overpressure and extreme winds, fires

nuclear explosion radiation types

initial and delayed

initial radiaton

• gamma rays and neutrons

• acute exposure can kill within days

delayed radiation

• energy not counted in yield

• longer term potential health effects

nuclear explosion above earth can cause

electromagnetic pulse (EMP) to fry all electronics

build a delivery system

hard to drop from airplanes because less survivable