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