Transcript P.1 Energy for the home

1.The time for half the nuclei in a radioactive sample
to decay.
A. Ionisation
2.These are emitted by the source in a smoke
alarm.
B. Cosmic Rays
3.This happens when nuclear radiation travels
through matter.
C. Proton
4.A nucleus of carbon-14 has eight of these.
D. Gamma Rays
5.This is one cause of background radiation.
E. Geiger-Müller tube
6.During beta decay the nucleus gains one of these.
F. Half life
7.What must be given out by the source used to
locate a blockage in an oil pipeline 2 m below
ground.
G. Alpha particles
8.This can be used to detect radiation.
H. Neutrons
Lesson.8:
Non-medical uses of Radiation
Objectives
Recall and describe the main non-medical
uses of ionising radiation.
Justify the choice of radiation used for a
particular purpose.
Judge the appropriate half-life for a source
used for a given purpose.
Tracers - finding leaks in pipes?
Smoke Alarms
Smoke alarms contain a weak source of alpha radiation.
The alpha particles ionize the air.
If there is smoke present, it
blocks some alpha particles
and ionization is reduced.
smoke
particle
α
This means that less current
is flowing through the air,
which causes the alarm to
sound.
α
Radioactive dating
Radioactive dating
Radiocarbon dating
=
Carbon - 14
14C
1:10,000,000 of the particles in all living things and
the same in the atmosphere
Half-life =
5730 years
Dating igneous rocks
=
Uranium – 238
238U
Eventually decays to Lead
Half-life =
4.5 billion years
Anagrams
bracon
tunco tear
blunt sea
crestar
positoe
heffalli
gantire corks
rutin dorush
Anagrams
carbon
count rate
unstable
tracers
isotope
half-life
granite rocks
turin shroud
Learning Objectives
•
State that radioisotopes are used as tracers in industry. MEDICAL USES ARE
COVERED LATER
•
Recall examples of the use of tracers:
• to track dispersal of waste;
• to find leaks/blockages in underground pipes;
• to find the route of underground pipes.
•
Describe how tracers are used in industry:
• radioactive material put into pipe;
• gamma source used so that it can penetrate to the surface;
• progress tracked with detector above ground;
• leak/blockage shown by reduction/no radioactivity after this point.
•
Describe that alpha sources are used in some smoke detectors.
•
Describe how a smoke detector with an alpha source works.
•
Recall that radioactivity can be used to date rocks.
•
Recall that measurements from radioactive carbon can be used to find the date
of old materials.
•
Explain how the radioactive dating of rocks depends on the calculation of the
uranium/lead ratio.
•
Explain how measurements of the activity of radioactive carbon can lead to an
approximate age for different materials:
• the amount of Carbon 14 in the air has not changed for thousands of years;
• when an object dies (eg wood) gaseous exchange with the air stops;
• as the Carbon 14 in the wood decays the activity of the sample decreases;
• the ratio of current activity from living matter to the activity of the sample leads
to a reasonably accurate date.