Transcript How does a smoke detector work?

How does a smoke detector
work?
Theme: Stability and Change
A review of what we’ve learned
about the nucleus so far!
Material for a smoke detector:
• Americanium-241
– Is a decay product of Pu-241
– What type of decay would that be?
– Write a balanced nuclear equation!
Where does radioactive plutonium come from?
What type of decay does Am-241
undergo?
• Alpha and gamma:
– Write a balanced nuclear equation:
Discuss in terms of conservation of energy and
matter!
What do alpha particles do?
• Ionize nitrogen
and oxygen in
air.
• This runs a
current.
• What does
smoke do to
the current?
How is this technology similar to a
photoelectric smoke alarm?
• What does the photoelectric effect tell us
about light?
What else do smoke alarms need to
run a current?
Public Service
Announcement:
What should you do
as you turn back your
clocks this
weekend?!?
What else do I need to know for my
test?
• Fission vs. Fusion…or both?
• Atomic Scientists…what understanding of
atomic structure did they give us and how?
• How to symbolize atoms, ions, and isotopes
• Themes: Structure Meets Function; Stability
and Change
– What did we learn in this unit to build on our
knowledge of these ideas?
Next long block…
• We will investigate a
radioactive decay
curve and connect
to the idea of a half
life.
• What does this
graph tell us about
carbon-14?
• Do all radioactive
elements have the
same half-life?
Homework Quiz
1) Be able to determine # protons, neutrons,
and electrons from a symbol of an ion, and be
able to write a symbol given information
about the atom/ion.
2) Using your notes, be able to write and
balance a specific type of nuclear equation.
3) Given data, determine the average atomic
mass of a sample.