Light, Spectra & Telescopes
📋 What it is
Splitting starlight into a spectrum reveals a star’s temperature, motion and chemical makeup.
🗣️ Coach says
Light is data. Passing starlight through a prism or grating spreads it into a spectrum, and the pattern of bright and dark lines is a chemical fingerprint — it tells us what a star is made of, how hot it is, and even whether it’s moving toward or away from us.
🧠 Memory hook
Spectrum = a star’s barcode: composition, temperature and motion, all from its light.
😂 Giggle
What did the telescope say to the astronomer?
"I see right through your questions — let me focus!"
😲 Whoa!
Helium was discovered in the Sun’s spectrum in 1868 — 27 years before anyone found it on Earth. It’s even named after Helios, the Sun.
✅ Quick check: What can a star’s spectrum tell us that a plain photo can’t?
Say your answer out loud first — then reveal.
Its chemical makeup, temperature and motion — the spectral line pattern is a fingerprint of the elements in it.
Spectroscopy decodes composition, temperature and velocity.
🧪 Try it! (2 minutes)
Look at light through a CD (a cheap grating) — the rainbow you see is a simple spectrum.