4. Complex Knowledge: demonstrations of learning that go aboveand above and beyond what was explicitly taught. 3. Knowledge: meeting the learning goals and expectations. 2. Foundational knowledge: simpler procedures, isolated details, vocabulary. 1. Limited knowledge: know very little details but working toward a higher level. Don’t spill the beads!!! How do stars differ from moons and planets, and from one another? How does the classification of stars help us understand how they evolve over their lifetimes? What are the different types of stars? What happens when different types of stars die? Why is it important for us to understand stars?

Draw this on your paper Use the whole page

Take 15 Marshmallows out of the cup Each marshmallow represents one proton Each bead represents one gamma particle (photon\energy) Take 15 Marshmallows (protons) out of the cup Put them all in the “Hydrogen” quadrant Write down how many there are Take 10 beads (gamma particle) out of the cup Set them off to the side

Model a main sequence star Your hands are now the core of a star where huge temperatures and pressures exist Use this temperature and pressure to fuse together Hydrogen nuclei (protons) into Helium nuclei For each helium atom created, place one bead next to it Continue this until all your Hydrogen supply is gone Write down how many Helium atoms there are Leave the 7 beads in the Helium quadrant. At this point 5 beads (energy) have been created in your Helium section. These are released in the form of heat.

Model an older star In older stars, much of their hydrogen has been converted into helium. If the temperature gets high enough, the cores of these stars can continue fusion through the triple-alpha process. To model this, take two of your helium nuclei (also called alpha particles) and smash them together. This forms a very unstable beryllium atom. If a third helium nucleus hits it before it disintegrates, a new element with six protons is formed. Smash another of your helium nuclei into your unstable beryllium atom. What element have you created? Place it in the correct quadrant For each carbon atom created, place a bead next to it Write down how many atoms of carbon there are

Once all of the Carbon has been created, you have now created a Red Giant star – with atoms of Hydrogen, Helium, and Carbon along with energy. Make sure you have filled out: Write the number of atoms that were formed for each element Hydrogen- Helium- Beryllium Carbon- How many gamma particles (photons) wre produced?

End Please make sure the beads end up back in the cups Please make sure the marshmallows end up in your belly or the trash!

Analysis on google classroom What is the name of the process by which stars generate energy? Atoms of which element are found at the beginning of this process? By the end of this activity, atoms of which two elements have been created? What is released as a result of this process? What pattern arose during this activity (Hint: look at the numbers) What can be inferred about the formation of heavier elements in stars? Hint: think quantity Large amounts of energy are released when nuclei combine. How many energy-producing reactions did you model? Why are Boron and Lithium generally not fused in a star? What is the atomic mass of Hydrogen?  What is the atomic mass of Helium?   How much total energy was released in this process?

Hydrogen and Nuclear fusion Record (draw, label, write) each step of the process. https://www.youtube.com/watch?v=W1ZQ4JBv3-Y

Change in mass Two 2H atoms can combine to form one 4He. When atoms fuse to form larger atoms, there is often a mass difference between the input atoms and the output atoms. Two 2H atoms can combine to form one 4He. The mass of two 2H atoms is 2x2.01=4.02 The mass of one 4He is 4.o0. The loss (.02) is converted into energy. (EMR)

Conservation of Mass and Energy In nuclear reactions, some mass is always converted to energy, so it seems that mass is lost, but the combination of mass and energy is ALWAYS conserved.

The basic formula for fusion is: 4 1 1 H  4 2 He + energy *Atomic number= protons *Atomic mass= protons + neutrons

How to calculate energy released: 4 1 1 H  4 2 He + energy 1. calculate total mass of the reactants and products 2. calculate the difference in mass to find the deficit 3. convert mass to energy. (E=mc2) 1 1 H = 1.007825 amu 4 2 He = 4.002603 amu

How to calculate energy released: 4 1 1 H  4 2 He + energy 1. calculate total mass of the reactants and products 2. calculate the difference in mass to find the deficit 3. convert mass to energy. (E=mc2) 4 1 1H - 4 2He 4.0313 amu - 4.002603 amu = .028697

4 1 1 H  4 2 He + energy 3. convert mass to energy. (E=mc2) How to calculate energy released: 4 1 1 H  4 2 He + energy 1. calculate total mass of the reactants and products 2. calculate the difference in mass to find the deficit 3. convert mass to energy. (E=mc2) c= 3X 108 m/s Mass 1 amu= 1.66 X 10-27 kg/amu Mass deficit = .028697 amu

E=4.3 X 10-12 Joules Answer: E= mc2 E=.028697 amu (1.66X10-27kg/amu) (3x 108)2 E=4.3 X 10-12 Joules .0000000000043 J

Update your sketch from yesterday… Fusion is when two elementary particles collide and combine or fuse to make -- even temporarily -- a new particle. A form (isotope) of hydrogen - Tritium - collides with another form of hydrogen - Deuterium - to form a new particle. The fused particle is not stable, and quickly decays into a very fast moving (hot) neutron , a helium nucleus , and energy.

Update your sketch

Summing it up… Summarize the equation E= mc2 and describe why it’s important. Also discuss the potential if we were able to convert mass directly to energy.

Homework: Due tomorrow!

http://www.pbs.org/wgbh/nova/einstein/experts.html Listen to 3 scientists describe the importance of E=mc2 Record their name and 1-2 sentences summarizing their thoughts on the equation, how it relates to stars, and why it’s important.