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presentation on radioactivity
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Radioactivity
Radioactivity- refers to the
spontaneous emission of particles or high-energy electromagnetic radiation from the nuclei of unstable atoms. This occurs due to the disintegration of the atomic nuclei.
Discovery of
RadioactivityIn 1898 a French scientist, Antoine Henri Becquerel discovered the ability for uranium to create a picture when exposed to light. Later, the husband and wife team of Pierre and Marie Curie studied and coined the term 'radioactivity.'
Antoine Henri Bacquerel
Importance of
RadioactivityRadioactivity has an
importance mostly when it comes to medicine, but is important for science in general. In medicine, radiation is used as a way of finding tumors within the body and then it is used to destroy them. However, in the realm of science, radiation can also be used to determine the age of the earth as well as the universe, itself. Unfortunately, as much as radiation can be helpful, in large amounts, it can be harmful or deadly to all living matter.
Dangers of
RadioactivityRadioactivity can damage
cells; can cause burns, diarrhea, vomiting, infertility, migraine and death. A huge amount of radioactivity can destroy many cells that the body cannot replace immediately, because after being inhaled or ingested, the particles settle in certain organs and start damaging the neighbouring cells.
Advantages and Disadvantages of
RadioactivityRadioactivity does have a
medical advantage. It is used for treatment of cancer patients to reduce or deplete tumors. Another advantage is that it kills microbes and permits carbon dating to take place. A disadvantage of radioactivity is that using it as a medical treatment does make the reproductive organs sterile. Over-exposure does have negative affects on your health. A large dose that is experienced all at one time can be fatal and is usually only an issue in the event of an explosion.
Types of RadioactivityThe types of radioactivity are
alpha, beta, and gamma, which are classified according to the charge if the electromagnetic rays they give off.
Alpha rays carry a positive charge, beta rays carry a negative one, and gamma rays are neutral.
Gamma ray
ISOTOPES
• Isotopes are atoms of an element which have the same proton number but different nucleon number.•Some isotopes are referred to as 'stable' and others as 'unstable' or 'radioactive'.
RADIOISOTOPES
• Radioisotopes are unstable isotopes which decay and give out radioactive emissions.• Radioisotopes are naturally occuring or
artificially produced.• Artificial radioisotopes can be produced
when certain nuclides are bombarded by high energy particles.
PROPERTIES OF RADIOISOTOPES• Emits radioactive radiation.
• Radioactive radiations can kill cells.
• Radioactive radiations have different penetrating ability with materials of different
thickness and densities.
• Radioactive radiations can cause cell mutation.
• Radioactive radiations can ionize molecules.
• Its activity decreases with time.
• Radioisotopes have the same chemical properties as non-radioactive isotopes of the
same element.
ARTIFICIAL RADIOISOTOPES
Example :When a nucleus of magnesium-24 is bombarded by a neutron,sodium-24 can be produced.
APPLICATIONS OF RADIOISOTOPES
Industry
Medicine To diagnose of thyroid disease using iodine-123
To treat an overactive thyroid gland and
certain kinds of thyroid cancer by using
sodium iodide labelled with radioactive
iodine
To detect position of blood clots
or thrombosis using Sodium-24
injected in the bloodstream
To detect and treat brain tumor using
phosphorus-32
To study the circulation
of iron in the blood
using iron-59 To sterilize medical
equipments and to destroy
cancer cells in radiotherapy
radioisotope cobalt-60 is
used
AGRICULTURE
To be used as tracers in the
effectiveness of fertilizers using nitrogen-
15 and phosphorus -32
To induce genetic mutation in a
plant in order to produce a better
strain which has higher resistance
against pest and diseases
Pests can be killed using
radioactive rays esp. using
gamma rays
To stop pests from reproducing, induced
mutation by using gamma rays can be
employed. But this has the probability of
producing GMO and resistant pests
ARCHEOLOGY
For determining age of fossils older than 60,000 years one uses
a potassium-argon dating technique. Potassium dating has a half
life of 1.3 billion years, thus allowing the age of rocks several
billions years old to be determined. A more accurate "argon-
argon" dating technique (determining the ratio between argon-39
and argon-40) has also been developed.
C-14 is another radioactive isotope that decays to C-12. This isotope is
found in all living organisms. Once an organism dies, the C-14 begins to
decay. The half-life of C-14, however, is only 5,730 years. Because of its
short half-life, the number of C-14 isotopes in a sample is negligible after
about 50,000 years, making it impossible to use for dating older samples.
C-14 is used often in dating artifacts from humans.
To measure geological time.
During the formation of rocks, some radioisotopes such as uranium-238 are
trapped. As the decay continues, the proportion of uranium-238 decreases slowly
resulting in the equally slow growth of its product lead-206. An estimate of the age
of the rock can be inferred from the relative proportions of lead and uranium in the
rock.
INDUSTRIES
1. The thickness of paper, plastics, clothes and metal sheets need to
be standardized and this is done by placing a radioactive source at
one side of the material and a detector on the other side.
2. For sheets of metal, gamma ray is used. For plastics, clothes and
paper, beta particles are used.
3. The detector will register a higher count if the material is too thin
and lower register if too thick. The computer will make adjustments
according to the thickness of the material.
This mechanism is also used to
ensure that containers such as
cans and food packages are filled
to the specified amount.
Radioisotope is added to engine oil so that
its level of wear and tear can be determined.
In order to kill germs that cause
food to spoil quickly, gamma
rays are used.
If exposed to gamma ray, latex becomes
harder without the need for adding
sulphur.
THANKYOU FOR WATCHINGDONE BY:
RISHITA SINGH