HS - ESS1.A (D) - The Formation of Elements - FINAL (WND 3/14/14)

Module: The Formation of Elements

DCI: ESS1.A (D) Other than the hydrogen and helium formed at the time of the Big Bang, nuclear fusion within stars produces all atomic nuclei lighter than and including iron, and the process releases electromagnetic energy. Heavier elements are produced when certain massive stars achieve a supernova stage and explode.

PE: HS-ESS1-2 Construct an explanation of the Big Bang theory based on astronomical evidence of light spectra, motion of distant galaxies, and composition of matter in the universe.

PE: HS-ESS1-3 Communicate scientific ideas about the way stars, over their life cycle, produce elements.

[Clarification Statement: Emphasis is on the astronomical evidence of the red shift of light from galaxies as an indication that the universe is currently expanding, the cosmic microwave background as the remnant radiation from the Big Bang, and the observed composition of ordinary matter of the universe, primarily found in stars and interstellar gases (from the spectra of electromagnetic radiation from stars), which matches that predicted by the Big Bang theory (3/4 hydrogen and 1/4 helium).]

[Clarification Statement: Emphasis is on the way nucleosynthesis, and therefore the different elements created, varies as a function of the mass of a star and the stage of its lifetime.] [Assessment Boundary: Details of the many different nucleosynthesis pathways for stars of differing masses are not assessed.]

The ideas are: 

- hydrogen and helium were formed at the time of the Big Bang

- all other elements (lighter than and including iron) are formed by stars

- the process that forms these elements is nuclear fusion  

- nuclear fusion releases electromagnetic energy

- heavier elements are produced when supermassive stars reach the supernova stage and explode

Again, we won't focus too much on the BB theory here, as there as an entire batch dedicated just to that one topic.  However, it will be useful to mention that the hydrogen and helium which provide the initial fuel source for stars is leftover from the big bang.  

Aside from that, we can ask general questions about how elements are formed within stars.  When it says communicate scientific ideas, that means that students should be able to select from a list of possible scientific ideas, the best (most accurate) idea.