Lesson 5: Nuclear fission/ fusion

Question 1

What is nuclear fission?

Answer 1

• Nuclear fission is the splitting of a large and unstable nucleus (ie.uranium/ plutonium) into two smaller nuclei.

Question 2

True or false. Nuclear fission happens on its own without triggering it.

Answer 2

• Spontaneous fission is rare.
• Usually, for fission to occur the unstable nucelus must first absorb a neutron.

Question 3

What happens during nuclear fission?

Answer 3

• Nucleus divides into 2 smaller nuclei.
• Nucleus emitts 2 or 3 neutrons
• Nucelus emits gamma rays

Question 4

True or false

The size of the daughter nuclei after an unstable nucelus has undergone fission are VERY different sizes.

Answer 4

• False.
• They are roughly equal in size.

Question 5

Give an example of a store that the energy released from nuclear fission converted to.

Answer 5

• All the fision products have kinetic energy.

Question 6

Nuclear fission…

What is the difference between chain reactions in nuclear reactors vs in an explosion?

Answer 6

• Chain reaction in nuclear reactor is CONTROLLED to control the energy released.
• The explosion caused by a nuclear weapon is caused by an UNCONTROLLED chain reaction.

Question 7

What is nuclear fusion?

Answer 7

• Nuclear fusion is the joining of two light nuclei to form a heavier nucleus.

Question 8

What happens to some of the mass of the nuclei during nuclear fusion?

Answer 8

• Some of the mass can be converted into the energy of radiation.