Name
Date
Section
http://astro.unl.edu/classaction/animations/sunsolarenergy/fusion01.html
EXPLORATION: Proton-Proton Chain
Visit StudySpace and open the “Proton-Proton Animation” for this chapter. Watch the entire simulation a number of
times and relate what is animated there to the reproduction given here.
1. Two hydrogen nuclei have collided to produce a new nucleus with two particles but only one positive charge. What
kind of particle carried away the other positive charge?
2. What happens to this particle and what results?
3. What is a neutrino? Did the neutrino enter the reaction or was the neutrino produced in the reaction?
4. What is the subsequent particle (neutron + proton) called?
5. Th is particle then collides with a hydrogen nucleus. Was charge conserved in this reaction? Explain.
6. What is a gamma ray? Did the gamma ray enter the reaction, or was it produced by the reaction?
7. What nuclei enter the fi nal collision? What nucleus is produced?
8. Make a list of the outputs from each reaction. Which of the outputs produce energy that leaves the Sun eventually
as light?
9. Which of the outputs is likely to stay in that form for a very long time?
KEY
3
Gamma rays (g)
g
e–
e+
n
1H
Proton
Neutrino (n)
Neutron
Positron (e+)
Electron (e–)
g
6
1H
1H
2
1H
1H
4
5
1H
1H
1
e–
n
e+
1H
g
10. Match the numbered step above with the description of the reaction, fi lling in letters next to the numbers.
a. Two helium-3 nuclei collide and fuse to form the more common form of the element: helium- 4.
b. At the instant the nuclei fuse and create a deuterium nucleus, a positron and a neutrino are created.
c. Two protons (H nuclei) meet under the extreme conditions present in the core of the Sun.
d. Positron + electron = annihilation; masses convert to energy in the form of two gamma-ray photons.
e. Two extra protons are released, available for further nuclear reactions.
f. In about 6 seconds a third proton fuses with deuterium nucleus to form He-3 + gamma ray.