OUTCOME
By the end of the lesson you will be able to describe the mechanism behind the sun's energy source.
The sun has been producing light for about five billion years but where does all its energy come from?
LEARNING TASKS
Explain
Fusion of nuclei releases energy until the the two nuclei have 26 protons.
What is changing as the proton count of the nucleus increases?
What is the force that holds the nucleus together?
What is the force that is pushing the nucleus apart?
How do these forces compare in small atoms (less than Iron)?
How do these forces compare in large atoms?
Why is it that in small atoms, combining the nuclei produces energy and in large atoms it requires energy?
EXPLORE
Write out the fusion equations for the sun.
Draw the proton proton chain
Calculate the energy produced in joules for each step and to complete the chain
If the sun intensity is given as 3.846Ă—1026 W how many
proton-proton chains per second does
this represent?
ELABORATE
Complete the questions 28-30 on the page 361
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