The Atom Bomb – a Classroom Demonstration!
Have you ever wanted to smash an egg and see just how far it splatters? This is your chance – and in a good cause. And it’s not just about understanding the power of atomic weapons in 1945 – it will help students understand why the possession of atomic weapons is such an issue in today’s world too. So, over to Ian Luff to describe this activity.
Note – the author and editor will not accept liability for any cleaning bills resulting from this activity!
It is very easy to assume that pupils fully understand the power of an atomic weapon. They do of course understand that an atomic explosion is large: but do they grasp just how large when compared to the power of conventional explosives? Clearly an atomic explosion provides a bigger bang: but how much bigger? Whereas the pupils of the 1950s 60s and 70s grew up with constant footage of atomic explosions on TV, that is no longer the case for current generations of pupils. Even yesterday’s pupils probably could not appreciate the full and relative destructive power of an atomic weapon from TV pictures; how much less chance will the pupils of today have?
Figures are no help. For example:
• World War Two - a medium sized high explosive WW2 bomb weighed 500 kilos.
• 1945 - the A bomb dropped on Hiroshima on 6th August 1945 contained the atomic equivalent of 13 000 tonnes of high explosive.
• 1950s - an early ‘thermo-nuclear’ Hydrogen bomb of the early 1950s would have been approximately 1000 times more powerful than the Hiroshima bomb.
So lots of noughts don’t help. Pupils eyes glaze over [mine too. Ed.]. They need a concrete demonstration.
Why does this matter? I would submit that if any pupil is to grasp the reasons for the Japanese surrender in WW2, the tensions of the Cold War period, the full importance of gaining peace in the Middle East and the vital importance of the security of Pakistani nuclear weapons in the struggle against al-Quaida he or she must have a secure conceptual grasp of the power of atomic and thermo-nuclear weapons. It is as vital a first order concept for the modern historian and modern citizen as that of understanding the military potential of the stone castle is to the mediaevalist.
1. Show the class a photograph of WW2 bomb damage - preferably the corner of a street or four or five destroyed/damaged houses. This is roughly the damage a 500kg high explosive bomb would have caused, a medium-sized World War Two bomb.
2. Now use an OS map or mapping website showing the place bombed in stage 1. The initial size you will use will be one inch to 300 yards for the site’s own map or one inch to 500yards for an OS. Ask a pupil to ring the destruction from the previous photograph on the actual map printout or bring a pupil out to indicate on the projected image.
3. Keep zooming out ‘Match of the Day’ style until the whole of your nearest city can be seen and pupil get the idea that the 500kg bomb would be a pinprick on such a scale. Hold this ‘pinprick’ thought – you’ll come back to it in a minute.
4. Now change focus. Place an A1 sized piece of sugar paper or flip-chart paper on the floor. Ask a pupil to draw an oval as large as possible on that piece of paper using a felt pen. Write your chosen city name across it. Put several other sheets of paper under and around your drawn oval. Place chairs/tables around the paper to keep pupils at a non splash distance!
5. Take an egg from your drawer or other place of concealment whilst pupils are looking at the drawing of the oval. Conceal it in your pocket.
6. Ask a pupil to mark the size of the 500kg bomb’s explosion [from the initial photograph] on this scale. The mark should be no more than a ball point dot – the pinprick from stage 3.
7. Now ask pupils to stand back. Explain that you are now going to demonstrate what a Hiroshima sized A bomb would do to the said city. Drop your egg and compare the result to the pin prick 500kg explosion.
(The Hiroshima bomb destroyed about 5 square miles of the city. Obviously the greater the height from which the egg is dropped the greater the area it will cover of the city you have drawn. Any city of less than 4 square miles in area would be totally destroyed. I suggest you practice dropping an egg beforehand to get the correct height so that you destroy the right amount of the city you have named and drawn. In London for example an Hiroshima sized bomb would destroy an area roughly the size of the City of London and Westminster. Ipswich would be 33% obliterated and so on. Relative areas of cities can be found on the web very easily.)
Why were atomic bombs so frightening? The Hiroshima bomb [simulated by your egg] killed approximately 66,000 people on the day it was dropped and about 33,000 died from the effects of radiation. It was the equivalent of 13000 tonnes of high explosive.
The later ‘thermo-nuclear H bombs were 1000 times more powerful than the Hiroshima bomb. Imagine dropping an egg 1000 times bigger on the paper city – or a real one. The largest hydrogen bombs developed contained the equivalent of 50 million tonnes of high explosive.
Now pupils should have a concrete conceptualisation of the power of atomic weapons relative to conventional explosive. Emphasise that conventional explosive is itself formidably powerful – as the injuries of our troops in recent years show.
If you wish you could now link this demonstration to contemporary concerns about which countries possess nuclear weapons.