Nuclear weapons: Which countries have them and how many are there?

 

What are nuclear weapons?

They are extremely powerful explosives.

You might remember the words atoms and isotopes from science lessons - they're involved in the process of triggering a nuclear blast.

The bombs get their energy from either splitting atoms or joining the tiny particles inside the atoms together. That's also why a nuclear bomb is sometimes called an atomic bomb.

IMAGE S

Image caption,

The US dropped an atomic bomb on the Japanese city of Hiroshima on 6 August 1945

Nuclear weapons release huge amounts of radiation - which can cause radiation sickness - so their actual impact lasts longer than the blast.

But they've only ever been used twice in history - against Japan in 1945 during World War Two where they caused huge devastation and enormous loss of life.

The radiation from the bomb dropped on the city of Hiroshima lasted several months and killed an estimated 80,000 people.

And the bomb dropped on Nagasaki killed more than 70,000 people.

They haven't been detonated in war since then.

Nine countries currently have nuclear weapons: the US, UK, Russia, France, China, India, Pakistan, Israel and North Korea.

The nuclear arms race has always centered around the U.S. and Russia.