Nuclear Fission and Fusion: Power of the Atom
Nuclear Fission and Fusion: Power of the Atom
Onderdelen in deze les
Nuclear Fission and Fusion: Power of the Atom
What do you already know about nuclear reactions?
Learning Outcome
At the end of the lesson you will be able to: define chain reactions, compare controlled and uncontrolled nuclear reactions, explain the use of control rods, describe nuclear fusion and its conditions, and evaluate the future of atomic energy.
What Is a Chain Reaction?
A chain reaction is a process where one nuclear reaction causes further nuclear reactions, creating a self-sustaining series. This happens when neutrons produced from one fission event trigger others nearby.
Controlled vs Uncontrolled Chain Reactions
Controlled chain reactions (in power stations) use control rods to absorb excess neutrons and regulate the process. Uncontrolled chain reactions (as in nuclear bombs) let the reaction rapidly increase without limits.
Chain Reaction in a Reactor
Not all neutrons from uranium fission cause more fissions because some escape the fuel and enter the reactor vessel, making them unavailable for further reactions.
Mini Whiteboard Activity: Sequence Challenge
If the uranium atom decay sequence is 1, 3, 9, 27, how many atoms are split in the 25th term? Show your calculation.
This is a geometric sequence: 3^(n-1). For the 25th term: 3^24. Write your answer on your mini-whiteboard!
Answer Method
Question
Keeping a Chain Reaction Under Control
Boron control rods absorb neutrons, preventing excess fission. Without them, the chain reaction could become dangerous, as happened at Chernobyl during a safety test gone wrong.
Nuclear Fusion: Stars and the Future
Nuclear fusion joins two light nuclei to form a heavier one, releasing energy. It powers the stars and requires very high temperature and pressure.
Fusion in Stars
Scientists are working on reactors, but controlled fusion for electricity is not yet practical. Fission is still used instead. Cold fusion claims in the 1990s stalled real research.
Fusion on Earth?
Whiteboard Challenge: Fission vs Fusion
On your mini whiteboards, list the differences between nuclear fission and fusion. Which products are made, and why can fusion make heavy elements?
Reflect & Discuss: Safety and the Future
Do you think nuclear power stations are safer now than in the past? What lessons were learned from Chernobyl, and how will future developments in fusion change our energy use?
Write down 3 things you learned in this lesson.
Write down 2 things you want to know more about.
Ask 1 question about something you haven't quite understood yet.
