Unit 18 Transmutations, Fission, and Fusion
-
Upload
olympus-high-school-jeff-taylor -
Category
Technology
-
view
3.316 -
download
2
Transcript of Unit 18 Transmutations, Fission, and Fusion
Unit 18
Transmutation, Fission, and Fusion
Fusion• The combination of two smaller
atoms into one larger one.
Hydrogen
HydrogenHelium
Lithium
Beryllium
Fusion Makes Larger Elements
Fusion is Hard!• Because the protons repel each other, getting two
atoms close enough to fuse is hard.• It takes temperatures approaching 10 million degrees
to have them travel fast enough to overcome the electrostatic repulsion
Strong Nuclear Force
• The strong nuclear force is the force that holds the nucleus together.
• All Nucleons are attracted to each other.• Because + protons repel each other
(electromagnetic force), the presence of neutrons helps bind the nucleus together.
++
Electromagnetic Force
Strong Nuclear Force
+N
Strong Nuclear Force
NN
Strong Nuclear Force
Strong Nuclear Force• It only acts within the nucleus• Fusion can only occur if protons are brought
within the nucleus.• One approach is to shoot particles at each
other at near the speed of light.
Fusion Releases Energy• When fusion occurs, some of the matter is
converted to energy and that energy is released as heat.
Stars are Element Makers• Medium stars like our sun mostly convert Hydrogen to Helium.
• Later, it will convert Helium to Carbon.
• Giant stars can fuse higher atoms to larger elements.
The Interior of a Giant Star
Super Nova
• Brighter than a galaxy!• Shockwave spreads heavier
elements across galaxy• Those heavy elements
condense into planets
Human Induced Fusion
• Hydrogen Bomb
Fission
• When an atom splits into two smaller atoms.
• The release of the strong nuclear force releases energy in the form of heat.
Nuclear Power
• Controlled fission reactions can generate heat to boil water to energy electricity.
Atomic Bomb
• Uncontrolled fission reactions
Critical Mass
• Fission can only occur as a chain reaction, if you have the critical mass.
• Otherwise, the neutrons simply run out of material to split.
How to Make The Bomb
• Have two uncritical masses separated from each other.
• Using dynamite, you can launch the masses together beginning the nuclear reaction.
Nuclear Transmutation• New elements or isotopes can be created by
adding particles to elements or splitting atoms.• These are generally done using particle
accelerators.• These speed particles at each other near the
speed of light to overcome electrostatic repulsion.
Nuclear Transmutation• Most of the “artificial elements” have been
created by adding particles to large atoms.
Cf249
98
C12
6
Rf257
104
4NCalifornium Carbon Rutherfordium
Particle Accelerators
Magnets Are Used to Move Particles
Particle Collider
Collision of Gold Particles