learning objectives: where do the elements come from? what can we learn from telescopes? how do...
TRANSCRIPT
Learning Objectives:• Where do the elements come from?• What can we learn from telescopes?• How do heavy elements form?
The equation below shows a typical fusion reaction that occurs in stars. It is interesting to note that the overall mass of the reactants is bigger than the overall mass of the products. Drag the labels in the correct place.
Where do the elements come from?
eHeH 01
42
11 24
Helium Ion Positron Hydrogen Ion
What happens to the missing
mass?
Why do you think two anti-electrons
are released?
Is this equation balanced? In what sense is/isn’t it?What happens to the
reactants in this process?
ALT + Click to edit this text, or delete and use INK for PowerPoint (the interactive pen in the bottom left corner) to write your conclusions!
ALT + Click to edit this text, or delete and use INK for PowerPoint (the interactive pen in the bottom left corner) to write your conclusions!
Einstein discovered that:
Where do the elements come from?
2mcE
Reactants mass = 6.69x10-27 kg
Do you think this energy is large or
small? Why?
How many reactions like this one do you think occur in a star every second?
eHeH 01
42
11 24
Use the information below and theabove equation to work out the energy released by the fusion reaction
Products mass = 6.64x10-27 kg
What do E, m and c mean?
What other reactions could occur in a star? Would they produce
more or less energy?
The binding energy per nucleon is a measurement of the energy that holds each particle (nucleon) in the nucleus of an atom.
Aver
age
Bind
ing
Ener
gy p
er
Nuc
leon
(1.6
6 x
10-1
3 J)
What can you notice about the
Binding Energy per Nucleon in different
elements?
Compare the B.E. Per Nucleon of He
and H. What can you notice?
Could you use this graph to predict the energy released by nuclear reactions?
Explain your answer
Which is the most stable element? Why did you choose that
one? Where do the elements come from?
Drag the labels in the correct place on the graph.
Aver
age
Bind
ing
Ener
gy p
er
Nuc
leon
(1.6
6 x
10-1
3 J)
In this region nuclear fusion happens
In this region nuclei are very stable
In this region nuclear fission happens
What can we learn from telescopes?
The next three images show the same region of rapid star formation in the Orion Nebula and the wavelengths emitted by the cosmic gas surrounding these newly born stars.
Use the information in these images to discuss the possible consequences of the presence of these molecules in such regions.
What types of molecules are
these?
What elements can you spot in this
emission spectrum?
What would your Biology teacher associate these molecules with?
What can we learn from telescopes?
Orion Nebula (Herschel Space Observatory)
What would you Chemistry teacher
associate these molecules with?
Do you think Scientists expected
to find these molecules in young
star forming regions? Explain your answer.
Were you expecting to find these
molecules in young star forming regions?
What other elements are
formed in a young star?
Would you expect to find heavier elements like Iron in this region?
Why?What can we learn from telescopes?
What do the sharp peaks in the spectral
graph mean?
Which molecule is most abundant in this star forming region?
Why are these molecules important?
Why are Scientists interested in them?
What can we learn from telescopes?
Orion Nebula (Herschel Space Observatory)
Do you think Scientists are looking at a particular part of
the EM Spectrum here? Why?
What is this type of star called?
In what stage of its life is this
star?
What will happen to this star eventually
according to the theory of evolution
of stars?
What can we learn from telescopes?
VY Canis Majoris (Herschel)
What elements would you expect this star to produce when it comes
to the end of its life?
Why is this called Tycho’s
Supernova?
What elements can you spot in this
emission spectrum?
Compare the elements from this supernova with the
elements surrounding young stars. What can you
notice?
How do heavy elements form?
Tycho's Supernova
Would we be able to see these Supernova remnants, if we used the same instruments
Thyco used? Why?
Complete the postcard below to tell Tycho Brahe how much we have discovered about “his” Supernova and other stars with modern telescopes
Tycho Brahe
Benátky nad Jizerou
Czech Republic
11th November 1572Front of Postcard
Back of Postcard
How do heavy elements form?
• Where do the elements come from? A variety of elements are found in regions surrounding relatively young stars
• What can we learn from telescopes?Modern telescopes (especially space telescopes) allow us to observe all the EM waves emitted by stars, not just visible light
• How do heavy elements form?Heavy elements like Iron are found in remnants of dead stars (Supernovae) and this suggests that such elements form in the last stages of the life of a star
Learning outcomes