Question

How can scientists use the spectrum of a star to determine what it is made of?

Answer 1

There is a known way to determinate that

Explanation:

Each element have an a electromagnetic spectrum of emision and absorption, each code for each element has been experimentally determined, by zooming the light of a star and throwing it through a prisma the light will be suitable to determinate his electromagnetic spectrum

The following is the spectrum of the sun

These are the light spectrum of emision of differents kinds of elements