We’ve reached the end our our learning this school year. Appropriate, perhaps, that we end where we began: in the stars. Way back in Unit 1, you learned that stars fuse lighter elements like hydrogen and helium to form heavier elements up through iron. Elements with more protons than iron are created when stars go supernova. Plants and animals (yep – humans are animals) are made of star stuff – we are quite literally the product of exploding stars.
We also conducted flame tests, showing that metal cations are responsible for producing specific colors of flame when ionic compounds are burned. Now we understand that our perception of color is a result of photoreceptors in our eyes being capable of detecting specific wavelengths of electromagnetic radiation. When those receptors are activated, they send information to our brain which then decodes the signal into our perception of light and color.
When we look up at the stars, we are looking back in time, as it takes time for light to travel from its source to our eyes here on Earth. The more distant the object, the further back in time we see. It’s not too hard to imagine there might be organisms billions of light-years away that witnessed the supernova (singular) or supernovae (plural) that launched the atoms within you and me toward our remote location within the Milky Way galaxy. The force of gravity eventually caused those atoms to coalesce to form our Sun and the planets that orbit it, including the Earth. After 4.5 billion years, here we are, studying the stars:
Anyone who would like to invest further in their understanding of the stars should email me for a copy of the handout that goes along with the Star Spectra Gizmo. This activity is purely optional and available for your own personal growth. It will not be entered in the grade book.
Return to Week 38 – Light and Color and continue working.