Learning Objectives - After this activity, students should be able to:
Describe atomic structure including sub-atomic particles and their
charges
Define fusion reactions
Understand the differences in the isotopes of hydrogen
Model a fusion reaction to understand how nuclei come together and
how that affects energy
Using the mass deficit to understand nuclear energy
Design a project to explain fusion using art and/or media
Introduction:
Fusion is the process that powers the sun and the stars. In one
example of this type of reaction, two atoms of hydrogen combine together
to form an atom of helium. In the process, some of the mass of the hydrogen
is converted into energy. The easiest fusion reaction to make happen
combines deuterium with tritium to make an atom of helium. Nuclear fusion
depends on three things; high density of particles, close proximity of the
particles to one another and a high rate of speed. Since we cannot duplicate
the high gravitational field of the sun (which causes the high density—
specifically atoms being very close together), we can increase the nuclei’s
rate of speed by heating to more than 4 times the temperature of the sun.
The chemical formula for water is H
2
O, so there are 2 hydrogen atoms in
every water molecule. One out of every 6500 atoms of hydrogen in ordinary
water is deuterium, giving a gallon of water the energy potential of 300
gallons of gasoline. In addition, fusion is environmentally friendly because it
produces no combustion products or greenhouse gases.
While fusion is a nuclear process, the products of the fusion reaction (helium
and a neutron) are not intrinsically radioactive. Short-lived radioactivity may
result from interactions of the fusion products with the reactor walls, but
with proper design a fusion power plant would be passively safe, and would
produce no long-lived radioactive waste. Design studies show that electricity
from fusion should eventually be about the same cost as present day
sources.
We’re getting close! While fusion sounds simple, the details are difficult and
exacting. Heating, compressing and confining hydrogen plasmas at 100
million degrees is a significant challenge. A lot of science and engineering
had to be learned to get fusion to where we are today.
Magnetic fusion programs expect to build their next experiments, which will
produce more energy than they consume within the next 15 years. If all goes
well, commercial application should be possible by the middle of the 21st
century, providing humankind a safe, clean, inexhaustible energy source for
the future.
Magnetic Fusion: Magnetic fields affect the flow of electricity, simply by
directing how electrons move. Magnetic fusion uses magnets to fuse
hydrogen particles together to form plasma. The energy released from 1
gram of fused Deuterium equals the energy from about 2400 gallons of oil.
That is a LOT of clean energy to help us answer our energy challenges!
Activities:
Materials:
Copies of Mini-Modeling template
Mini-candies
2 long magnets and iron filings
Copies of A STAR FOR US illustrated science booklet
Props for multimedia presentation
Recording device (a smartphone will suffice)
In the following activities, you will learn about the structure of sub-
atomic particles, specifically the difference in the isotopes of hydrogen.
You will use your knowledge of the atomic structure of hydrogen and its
isotopes to design a multimedia presentation describing what happens
in a fusion reaction. The Power-Up activities that support this lesson will
help you understand the particles that contribute to a fusion reaction as
well as having a basic understanding of the transfer of a loss in mass, to
energy.
Mini-Modeling the Atom: Have you ever wondered what constitutes the
atoms that make up everything we know? This activity will help you
visualize these particles, where they are located in the atom, and the
difference in their charges.
As we talk about sub-atomic particles, what do they look like in an atom
and how are they arranged? Can you model the difference in the three
isotopes of hydrogen?
You will need the attached Mini-
Modeling Map and mini-candies.
You can choose one color of the
candy for protons, a different
color for neutrons, and a third
color for electrons. Can you
model the three different
isotopes of hydrogen on your
modeling map? Can you model
an atom of helium that was
formed by fusion?
Infographic by Department of Energy
Examine your models and compare to the illustration. Refer to the
power-up activity for a more detailed explanation for this activity.