““The World We Create”The World We Create”NATS 101NATS 101Section 6Section 6
New Homework Posted in D2L.
Due on Tuesday at 2 PM.
01/28
Why do some countries use more nuclear energy than others?
Central Questions
What is the difference between producing chemical energy and nuclear energy?
What do we mean by ionizing radiation?
How can we detect the presence of ionizing radiation in our surroundings?
Limited SourcesThe earth’s reserves of fossil fuels are limited:
2007 2020 2030 2040 2050 2300
Gas begins to run out
Oil begins to run out
Coal begins to run out
Because of this we need to: Conserve; Improve efficiency; Develop new chemical fuels; Search for alternative sources of energy.
Country # Nuclear Power Plants
% Electricity from Nuclear Power
U.S. >100 21
France 56 75Japan 40 26
UK 37 20Sweden 12 46
Nuclear Energy Output Different Countries
Different Choices
What factors may have influenced these countries’ choices?
(political, economical, social, environmental, historical, etc.)
Are you for or against the use of Nuclear Energy?
Why?
You have 3-4 minutes
Why are we afraid of Nuclear Energy?
Two different types of processes:
Chemical Reactions Nuclear Reactions
Atoms only rearranged Mass is not “lost” Energy is produced
C(s) + O2(g) CO2(g)235
92U + 10n
14156Ba + 92
36Kr + 3 10n
New atoms form Mass is “lost” Vast amounts of energy is produced
Atomic Structure
Atoms of the same element have the number of protons in the nucleus (Atomic Number)
Atoms of the same element that differ in the number of
neutrons are called ISOTOPES
(they have different mass number)
(Number of protons)
(Number of protons plus neutrons)
Nuclear Fission
23592U + 1
0n 14156Ba + 92
36Kr + 3 n10 + energy
A small amount of mass is transformed into a huge amount of energy. E = mc2
We have developed strategies to split atomic
nuclei apart (fission).
Neutron bombardment
Some mass is lost in the process!
Let’s Calculate
If you induce the fission of 1.0 g of Uraniumyou get 90,000,000,000,000 = 9.0 x 1013 J
During the nuclear fission of Uranium, 0.1% of the mass is transformed into energy.
E = mc2 C= 300,000,000 m/s
Equivalent to the energy
Released by 33,000 tons of TNT
Needed to raise 700,000 cars 6 miles into the sky
Turn 8.7 million gallons of water into steam
Radiation
Most of the energy generated during a nuclear process is released in the form of RADIATION.
Radiation is energy in the form of waves or particles sent out over a distance.
Microwave radiation
Ultraviolet light
X-rays
Infrared radiation
Visible light
Matter InteractionsDifferent types of radiation interact differently
with matter.
You have 8 minutes
Make a drawing that models what you think happens when each type of radiation interacts with molecules
or atoms in your body.
Microwave radiation
Ultraviolet light
X-raysInfrared radiation
Visible light
Non-Ionizing Radiation:
Low energy levels: Strong enough to influence the atoms or molecules it contacts
(translation, rotation, vibration), but not strong enough to affect their structure.
Ionizing Radiation:
Higher energy levels: It has enough energy to affect the structure of the
atoms. Particularly, to remove electrons (ionize).
Radiation
Radioactivity
Some substances, such as uranium and plutonium, emit ionizing radiation spontaneously
(you don’t need to split them).
This property is called Radioactivity
Radioactivity results from changes in the atomic nuclei of the
atoms
How do we detect and measure it?
Geiger CounterThe Geiger Counter measures the number of ionizing events
per unit of time (counts per minute or CPM).
(+)
How would you design/build an instrument like
this?
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