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clokey43
10-28-2005, 05:54 AM
Ok, so I've got to do a presentation. My topic question is 'What are stars made of? How do we know?'. I'm not interested in astrology or cosmology in the slightest. I wondered if any of you know and websites or usefull books / magazines that can help me do a 7 or 8 slide presentation.

I will be very greatful if you could help.

The_Hombre
10-28-2005, 05:59 AM
Click Me (http://www.cambridge.org/uk/catalogue/catalogue.asp?isbn=0521801052).

If that doesn't work there are loads of other similair resources at Google (http://www.google.com).

clokey43
10-28-2005, 06:02 AM
Excellent, that should get me started, thanks.

The_Hombre
10-28-2005, 06:11 AM
8 slides is easy. Try doing 30+. I've just finished my BSc at Manchester Uni; shortest presentation I had to do was 20 minutes, longest presentation was an hour. Ack!

STAY AT COLLEGE AS LONG AS YOU CAN!!!

clokey43
10-28-2005, 06:13 AM
Yeah i know what you mean. Last year our course work was to prepare a presentation on a material. I did flint. It was 45 mins long, half hour longer than the rest of the class. I got an A grade for it though. Im in my last year not sure if I want to do a degree in physics or law yet though.

sKratch
10-28-2005, 06:23 AM
Spectroscopy.

clokey43
10-28-2005, 06:24 AM
Whats that?

clokey43
10-28-2005, 06:59 AM
Ok so anyway, I have half of it done, what are stars made of. However, I have been googling for like 20mins to find How do we know? I haven't found the answer. Any one got any ideas? What research has been done to find out what stars are made of?

The_Hombre
10-28-2005, 07:05 AM
Try this (http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961112a.html).

If that isn't helpful, just blab on about evolution of science, greater understanding of the universe over the last 300 years, etc...

Also, search for "Timeline of Star Exploration" or the "Big Bang" or something like that.

sKratch
10-28-2005, 07:42 AM
Ok so anyway, I have half of it done, what are stars made of. However, I have been googling for like 20mins to find How do we know? I haven't found the answer. Any one got any ideas? What research has been done to find out what stars are made of?
Let me try that again.

Spectroscopy.

Stars are made up of various elements. These elements emit visible light when excited electrons return to their ground state. Every element has a unique series of spectroscopic lines, and so the composition of stars can be determined by studying these lines. For example, Hg gives off something like this if I remember:
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clokey43
10-28-2005, 07:44 AM
oh ok, now I understand. Thanks

clokey43
10-28-2005, 07:56 AM
Try this (http://imagine.gsfc.nasa.gov/docs/ask_astro/answers/961112a.html).

Thanks for this, it helped me finish my presentation. Thanks

Endymion
10-28-2005, 10:19 AM
as skratch said, if you give an atom energy one or more of its electrons jump to a higher orbital level (look up the bohr atom, i'm not going to explain all of that) and then back down again. since the orbitals are only at particular energy levels, there's a set energy between any two orbitals of the particular atom. each element's orbitals are different. so by looking at the energy spit out of the sun, we can match light frequencies to orbital jumps and find what atoms are up there. in fact, the element helium was first discovered because it was seen in the sun. it's a rather rare element here on earth. there's also some stuff about absorption lines if you want more detail.