1. Learning Objectives: Where do the elements come from? What can we learn from telescopes? How do heavy elements form?

2. 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? Helium IonPositronHydrogen 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?

3. 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? 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? Use the information below and the above 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?

4. The binding energy per nucleon is a measurement of the energy that holds each particle (nucleon) in the nucleus of an atom. Average Binding Energy per Nucleon (1.66 x 10 -13 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?

5. Drag the labels in the correct place on the graph. Average Binding Energy per Nucleon (1.66 x 10 -13 J) In this region nuclear fusion happens In this region nuclei are very stable In this region nuclear fission happens

6. 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.

7. 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?

8. 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?

9. 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?

10. 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?

11. 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?

12. 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 11 th November 1572 Front of Postcard Back of Postcard How do heavy elements form?

13. 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