little kid scientist :): RADIOACTIVITY

NUCLEUS OF AN ATOM

THE COMPOSITION OF THE NUCLEUS :

a nucleus consist of the number of protons and neutrons. protons and neutrons are collectively referred to as nucleons because they are found in the nucleus.

PROTONS AND NUCLEON NUMBER :

the protons number,Z, is defined as the number of proto

ns in a nucleus.

the nucleon number,A, is defined as the total number of protons and neutrons in a nucleus.

NUCLIDE

a nuclide is an atom of a particular structure. each element has nucleus with specific number of protons. for example, a helium nucleus always has 2 protons. carbon nucleus always has 6 protons.

ISOTOPES

isotopes are atoms with the same number of protons but difference number in nucleon number.

RADIOACTIVITY DECAY

radioactivity is the spontaneous and random disintegration of an unstable nucleus accompanied by the emission of energetic particles or photons.

after the discovery of radioactivity, scientist soon reliesed that there are more that three different type of radiation emitted from a radioactive n

ucleus, three of these are:

A) alpha

b) beta

C) gamma

DETECTORS OF RADIOACTIVE EMISSIONS

consist of four types :

A) golf leaf electroscope

B) cloud chamber

c) bubble chamber

radioactive is a very sensitive and easily to explode. we can see the nuclear reaction that occur in Chernobyl many years ago .

the story of CHERNOBYL DISASTER:

The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986, at the Chernobyl Nuclear Power Plant in Ukraine(then in the Ukrainian Soviet Socialist Republic, part of the Soviet Union). It is considered the worst nuclear power plant accident in history and is the only level 7 event on the International Nuclear Event Scale.
The disaster occurred on 26 April 1986, at reactor number four at the Chernobyl plant, near the town of Pripyat in the Ukrainian Soviet Socialist Republic (USSR), during an unusual and (as carried out) unsafe systems test at low power. A sudden rapid growth in power output took place, and when an attempt was made for emergency shutdown, an unexpected and more extreme spike in power output occurred which led to a reactor vessel rupture and a series of explosions. This event exposed the graphite moderator components of the reactor to air and they ignited; the resulting fire sent a plume of radioactive fallout into the atmosphere and over an extensive geographical area, including Pripyat. The plume drifted over large parts of the western Soviet Union, Eastern Europe, Western Europe, and Northern Europe. Large areas in Ukraine, Belarus, and Russia had to be evacuated, with over 336,000 people resettled. According to official post-Soviet data, about 60% of the fallout landed in Belarus.
The accident raised concerns about the safety of the Soviet nuclear power industry as well as nuclear power in general, slowing its expansion for a number of years while forcing the Soviet government to become less secretive about its procedures.
The countries of Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination and health care costs of the Chernobyl accident. A 2005 report prepared by the Chernobyl Forum, led by the International Atomic Energy Agency (IAEA) and World Health Organization (WHO), attributed "fewer than 50" direct deaths (including nine children with thyroid cancer) and estimated that there may be up to 4,000 additional cancer deaths over time among the approximately 600,000 most highly exposed people. Although the Chernobyl Exclusion Zone and certain limited areas remain off limits, the majority of affected areas are now considered safe for settlement and economic activity.

Radio-operated bulldozers being tested prior to use

Aerial view of the damaged core. Roof of the turbine hall is damaged (image center). Roof of the adjacent reactor 3 (image lower left) shows minor fire damage.