Upload
minh-hayat
View
223
Download
1
Embed Size (px)
Citation preview
7/27/2019 6.1 Radioactive Substances
1/26
Chapter 6Nuclear
Energy
7/27/2019 6.1 Radioactive Substances
2/26
7/27/2019 6.1 Radioactive Substances
3/26
6.1 Radioactive substances
7/27/2019 6.1 Radioactive Substances
4/26
Learning Outcomes
State what is radioactive substances
Give the examples of radioactive
Substances
Explain the process of radioactive decay
State the uses of radioactive substances
7/27/2019 6.1 Radioactive Substances
5/26
7/27/2019 6.1 Radioactive Substances
6/26
7/27/2019 6.1 Radioactive Substances
7/26
7/27/2019 6.1 Radioactive Substances
8/26
7/27/2019 6.1 Radioactive Substances
9/26
Radioactive Decay
When the radioactive nuclei break-up ordecay, 3 types of radioactive particle
or radiation is emitted;
i) Alpha()-Positive charge
ii) Beta()-Negative charge
iii) Gamma()-Neutral
Spontaneous process
7/27/2019 6.1 Radioactive Substances
10/26
7/27/2019 6.1 Radioactive Substances
11/26
Types of Radiation
7/27/2019 6.1 Radioactive Substances
12/26
Alpha()
radiation
Beta()
radiation
Gamma() radiation
(a)Nature Helium
nucleus
Electron Electromagnetic wave
(b)Charge Positive ( + ) Negative (-) Neutral
(c)Penetrating
powerLow High Highest
(d)Canstopped by
A sheet ofpaper
5 mmaluminium
25mm lead block orconcrete wall
e) Movement/
Speed
Slowly Very Fast Speed of light
(f)Ionizing
power
High low Very low
(g)Mass Heaviest heavy No mass
(h)Particles
or rays 2 protons &2 neutrons
One atom Ray
7/27/2019 6.1 Radioactive Substances
13/26
Penetrating Power of theRadiation
7/27/2019 6.1 Radioactive Substances
14/26
7/27/2019 6.1 Radioactive Substances
15/26
7/27/2019 6.1 Radioactive Substances
16/26
Uses of radioactive substance
on daily lifeField UsesIndustry Detection of leakage in underground pipes
Detection of thickness of paper, metal and plastics
Agriculture To study the absorption and distribution of elements
Gamma radiation is used to sterilize crop pests (abiological control method)
Medicine As radiotherapy treatment for cancer patientTo sterilize syringes and surgical instruments
Archeology To determine the age of ancient artifacts (carbon
dating)Foodtechnology
To preserve food
7/27/2019 6.1 Radioactive Substances
17/26
The Uses of Radioactive Substances
Agriculture1.Gamma rays are used to- Produce new breeds of quality plants- higher yield,
earlier maturity, better nutritional value, greaterresistance to disease.
- Induce mutation in plant and animal
2. Phosphorus-32 are used as; detectors to study the absorption and use of fertiliser
(phosphate) by plants. Help farmer to determine the amount of fertiliser
need for a crop. Scientist understand how plant use phosphorus to
grow and reproduce.
7/27/2019 6.1 Radioactive Substances
18/26
Medicine1.Gamma rays
from cobalt-60 areused to kill cancercells (radiotherapy)
also used to steriliseinstruments used inan operation
Eg: plastic syringes
7/27/2019 6.1 Radioactive Substances
19/26
iodine-131
Check the function of bodyorgan.
to detect any damage tothe thyroid gland and check
the uptake of iodine bythyroid gland.
Patient drink liquid containiodine-131
Detector measure how fastiodine accumulates in thethyroid gland.
7/27/2019 6.1 Radioactive Substances
20/26
Sodium-24
To detect the locationof blood clot
Inject sodium-24 intoblood stream anddetect where the flowstop.
7/27/2019 6.1 Radioactive Substances
21/26
Industry
Geiger-Mller countercan detected theleaking pipes inunderground.
7/27/2019 6.1 Radioactive Substances
22/26
industry
Beta particles can
be used to control
the thickness of the
paper, plastic oraluminium foil in the
mills and also be
used to ensure that
bottles andcontainers are filled
to correct level.
Figure 6.4 The thickness of paper canbe controlled by measuring how much
beta radiation passes through the
paper to Geiger counter.
( page 139)
7/27/2019 6.1 Radioactive Substances
23/26
Food Preservation
Gamma rays canbe used to kill
bacteria, mould
and insects infood even after it
has been
packaged.
This process calledfood irradiation.
7/27/2019 6.1 Radioactive Substances
24/26
Radioactive Dating When animals and plants
die, they stop takingcarbon, the amount ofcarbon-14 begins to declineat a know rate.
The age of the remains canbe determined bymeasuring the amount ofcarbon-14 that remains.
Method above calledcarbon-14 dating.
Archaeologists use thismethod to estimate the ageof ancient remains such asthe age of a dinosaur.
7/27/2019 6.1 Radioactive Substances
25/26
Exercise 1
1.Give the meaning of radioactivesubstances.
2.Give two examples of radioactivesubstances and two of radioisotopes.
3.State one use of radioactive substances ineach of the following field
i) Medicine
ii) Industry
iii) Agriculture
7/27/2019 6.1 Radioactive Substances
26/26
Production of Nuclear
Energy
Fission of Uranium-235 produce two new nucleus and releases nuclear
energy. This process is called fission of radioactive substance