Australian Biography – Sir Marcus Oliphant (1991)

Video Clip Synopsis:
The first atomic bomb was dropped on Hiroshima. Sir Mark Oliphant helped to create the bomb, but even though it ended the war he can never reconcile himself to the loss of civilian life.

Duration:
1min 35sec

Sir Marcus Oliphant and The Atomic Bomb consists of excerpts from the program Sir Marcus Oliphant (26 mins), an episode of Australian Biography Series 1 (7 x 26 mins), produced in 1991.

Sir Marcus Oliphant: Sir Marcus Oliphant is a founding father of the Australian National University in Canberra and a former Governor of South Australia. While at Adelaide University in 1927, he was accepted by Cambridge University, where he became part of a team whose task was to split the atom. During World War Two, he developed the centimetre wave radar. After the bomb was used against civilians in Hiroshima, he went on to devote his considerable scientific talent and energies to finding peaceful uses for atomic power.

Australian Biography Series 1: The Australian Biography series profiles some of the most extraordinary Australians of our time. Many have had a major impact on the nation’s cultural, political and social life. All are remarkable and inspiring people who have reached a stage in their lives where they can look back and reflect. Through revealing in-depth interviews, they share their stories - of beginnings and challenges, landmarks and turning points. In so doing, they provide us with an invaluable archival record and a unique perspective on the roads we, as a country, have travelled.

Australian Biography Series 1 is a Film Australia National Interest Program.

Curriculum Focus: Science
Year: 11-12
Theme: Science Work

The Structure of the Atom; Nuclear energy

There are many kinds of energy in the world such as heat, sound, light, movement, chemical and electrical energy. Energy is the ability to do work. Energy cannot be created or destroyed, but it can be changed from one kind into another.

Nuclear energy involves atoms and energy is produced when the nucleus of an atom changes.

Isotopes of an element are atoms that have the same number of protons in their nuclei, but they have different numbers of neutrons. Many isotopes are unstable or radioactive. They give off radiation and if they are very unstable they also split into two smaller atoms.

When a nucleus splits to form two new smaller nuclei, it will usually release two or three neutrons. These neutrons can go on to be grabbed by other nuclei that will then split, releasing more neutrons. These neutrons can also cause more atoms to split. This process is called a chain reaction.

The critical mass is the smallest amount of material that will allow a chain reaction to keep going by itself. For uranium-235 the critical mass is between 10 and 35 kilograms. The size of the piece of uranium metal used in the atom bombs dropped on Japan in 1945 was about the size of a grapefruit.

An atom bomb has a number of pieces of nearly pure uranium-235 or plutonium-239. These are all less than the critical mass. When the bomb is detonated, ordinary explosives drive the pieces together to make one piece that is above the critical mass. This causes an uncontrolled chain reaction and the bomb explodes.

South Australian Sir Marcus Oliphant was a nuclear physicist who worked at the Cavendish Laboratories in England. At the onset of World War 2, he was in charge of a team that successfully developed microwave radar.

During World War 2, Oliphant travelled back and forth between the USA and the UK, leading a team of British physicists who were collaborating with American scientists on the development of the first atomic bomb.

Discuss what students know about Japanese involvement in WW2 and the dropping of the bombs on Hiroshima and Nagasaki. What were the short term and long term effects if these bombs on the human population?

What happened in the nuclear weapons industry after WW2? Discuss the cold war. What are the issues surrounding nuclear weapons today?

Brainstorm famous Australian scientists and what they achieved. Why are scientists less well known than famous sports people or actors?

1. Before watching the video clip, students brainstorm all they know about nuclear energy and how nuclear bombs are fuelled.
2. Look up the meanings of the following words: nuclear, radioactive, atomic, fission, fusion, isotope, infidel, fall-out, radiation sickness.
3. Looking at the structure of the atom explain the following:
   • The difference between a non-radioactive isotope and a radioactive isotope?
   • The difference between alpha, beta and gamma radiation
   • Nuclear fission reactions. Give an example of a fission reaction of an isotope of uranium.
   • Nuclear fusion reactions using hydrogen as an example.
   • The link between a hydrogen bomb and the Sun.
4. Find out more about what effect the atomic bombs had on the Japanese population as well as the rest of the world. What is Hiroshima Day and when is it celebrated?
5. Debate the pros and cons of using the atomic bomb to end WW2.

Science Year 11-12, SOSE/HSIE Year 9-10, English Year 11-12