Transcript Origin of Chemical Elements

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.
What happens to
the missing mass?
Why do you think two
anti-electrons are
released?
4 H  He  2 e
1
1
What happens to the
Helium
Ionprocess?
reactants
in this
Where do the elements come from?
4
2
Positron
0
1
Is this equation
balanced? In what
sense is/isn’t it?
Hydrogen Ion
Einstein discovered that:
E  mc
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2
What do E, m and
c mean?
Use the information below and the
above equation to work out the energy
released by the fusion reaction
4 H  He  2 e
1
1
4
2
0
1
What other reactions could
Reactants
= Would
Products
occur inmass
a star?
they mass =
produce
more
6.69x10-27
kg or less energy?
6.64x10-27 kg
Where do the elements come from?
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?
What can you notice
about the Binding
Energy per Nucleon in
different elements?
Which is the most stable
element? Why did you
choose that one?
Where do the elements come from?
Average Binding Energy per
Nucleon (1.66 x 10-13 J)
The binding energy per nucleon is a measurement of the energy that holds each
particle (nucleon) in the nucleus of an atom.
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
Average Binding Energy per
Nucleon (1.66 x 10-13 J)
Drag the labels in the correct place on the graph.
In this region nuclear
fission happens
In this region nuclear
fusion happens
In this region nuclei
are very stable
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 can we learn from telescopes?
What types of
molecules are
these?
What would your Biology
teacher associate these
molecules with?
What can we learn from telescopes?
What elements can
you spot in this emission
spectrum?
What would you
Chemistry teacher
associate these
molecules with?
Orion Nebula (Herschel Space Observatory)
Do you think Scientists
expected to find these
molecules in young star
forming regions? Explain
your answer.
Would you expect to find
heavier elements like Iron
in this region? Why?
What can we learn from telescopes?
Were you expecting to
find these molecules in
young star forming
regions?
What other elements
are formed in a young
star?
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?
Do you think Scientists
are looking at a
particular part of the
EM Spectrum here?
Why?
What can we learn from telescopes?
Orion Nebula (Herschel Space Observatory)
What is this type of star
called?
What elements would you
expect this star to produce
when it comes to the end
VY Canisof
Majoris
(Herschel)
its life?
What can we learn from telescopes?
In what stage of its
life is this star?
What will happen to
this star eventually
according to the
theory of evolution of
stars?
Why is this called
Tycho’s Supernova?
Would we be able to see
these Supernova
remnants, if we used the
same instruments Thyco
used?
Why?
Tycho's
Supernova
How do heavy elements form?
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?
Complete the postcard below to tell Tycho Brahe how much we have
discovered about “his” Supernova and other stars with modern
telescopes
Dear Tycho,
You wouldn't believe what we have discovered
about Supernovae and stars with modern
telescopes...
Tycho Brahe
Benátky nad Jizerou
Czech Republic
11th
How do heavy elements form?
November 1572
Back
Front
of of
Postcard
Postcard
• 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