Add to table of contents: Color the Spectra Pg. 8 Electromagnetic spectrum Pg. 9

Herztsprung-Russell Diagram Attach to the top of page 9.

Herztsprung-Russell Diagram Use the H-R diagram to answer the following questions: What is meant by the word “magnitude”? What color are cooler stars? What color are hot stars? What are main sequence stars? What category of star is our sun? Using the diagram, how would you describe our sun?

Luminosity = Magnitude = brightness

Electromagnetic spectrum Stars emit all forms of electromagnetic energy. We can only see a very small part of it = visible light = colors.

Draw on page 9 Short wavelength Long wavelength

Visible light questions: What colors are on the visible light spectrum? What units are the wavelengths of light measured in? µm = micrometers or nm=nanometers What is the range of wavelengths of visible light? Which color has the longest wavelength? Which color has the shortest wavelength? What color would you expect to see at a wavelength of 0.45 micrometers? What color would you expect to see at 0.7 micrometers?

Every element, when illuminated, gives off an unique set of spectral lines called a “spectral fingerprint”.

A spectral fingerprint tells us: what gases(elements) are in a star how hot it is If it is moving towards us or away (blue shift/red shift)

Assignment:Color spectral fingerprints Color each line indicated on the spectral fingerprint worksheet.

1. Hydrogen 410 433 486 656

2. Helium 667 587 501 492 471 447 402

3. Carbon 412 470 488 500 509 510 538 567 569 592 605 659 680

4. Oxygen 410,413,423,440,442-450, 478,480 –blues red-640,650,668,672 Green-520, 533, 550 yellow-593,599, 604 orange-610,618,630

Combine H and He for #5 Copy lines from #1 H and # 2 He onto the line for #5. This is what happens when we are seeing more than 1 element’s light at the same time.