2. Radioactivity

4. 1896 Henri Becquerel was experimenting with a uranium compound to determine whether it gave off X-rays. 1896 Henri Becquerel was experimenting with a uranium compound to determine whether it gave off X-rays. He did prove their existence as well as the existence of other particles.He did prove their existence as well as the existence of other particles. Eventually these particles were called nuclear radiation.Eventually these particles were called nuclear radiation.

5. Marie Curie (Marya Sklodowska), a Polish scientist (former student of Becquerel) discovered a new radioactive element with her husband Pierre Curie and she named it Polonium after Poland.Marie Curie (Marya Sklodowska), a Polish scientist (former student of Becquerel) discovered a new radioactive element with her husband Pierre Curie and she named it Polonium after Poland. Later, they discovered Radium meaning “shining element” which was also radioactive.Later, they discovered Radium meaning “shining element” which was also radioactive. 1934 Marie Curie would die from radiation sickness due to the exposure. Her husband died from cancer in 1901.1934 Marie Curie would die from radiation sickness due to the exposure. Her husband died from cancer in 1901.

6. The Curies… 1934 1901

8. Nuclear Stability Binding energy is needed for the stability of a nucleus (associated with the nuclear strong forceBinding energy is needed for the stability of a nucleus (associated with the nuclear strong force High: stableHigh: stable Low: unstableLow: unstable Many elements have radioactive isotopes.Many elements have radioactive isotopes. Ex. Carbon 12: non-radioactive (coal, diamond, graphite) Carbon 14: radioactive (used for carbon dating) *a nucleus that is unstable can become stable by undergoing a nuclear reaction or change

9. Radioactivity The release of nuclear radiation in the form of particles and rays from a radioactive element

10. Alpha Particles Nucleus of He atom.Nucleus of He atom. WeakestWeakest Positive chargePositive charge Can burn flesh but stopped by paperCan burn flesh but stopped by paper

11. Beta Particles Electron formed in the nucleus when a neutron breaks apartElectron formed in the nucleus when a neutron breaks apart 10x stronger than alpha10x stronger than alpha Can pass through 3 mm of aluminumCan pass through 3 mm of aluminum

12. Gamma Rays Electromagnetic wave of high frequency and short wave lengthElectromagnetic wave of high frequency and short wave length StrongestStrongest Can pass through several cm of leadCan pass through several cm of lead

14. Radioactive Decay The spontaneous breakdown of an unstable atomic nucleusThe spontaneous breakdown of an unstable atomic nucleus Emits particles/rays to become lighter and more stableEmits particles/rays to become lighter and more stable

15. Alpha Decay Occurs when a nucleus releases an alpha particleOccurs when a nucleus releases an alpha particle

16. Beta Decay Loses a beta particle causing the # of protons to go up by 1.Loses a beta particle causing the # of protons to go up by 1.

17. Gamma Decay Release of gamma rayRelease of gamma ray Nucleus is not changed only lowered to a different energy levelNucleus is not changed only lowered to a different energy level

18. Radioactive Half-Life

19. The amount of time it takes the atoms in a given sample of an element to decayThe amount of time it takes the atoms in a given sample of an element to decay Helps determine the age of rocks and fossilsHelps determine the age of rocks and fossils Some are only seconds, others are billions of years of half-lifeSome are only seconds, others are billions of years of half-life Ex: 5,730 yrs. Carbon 14Ex: 5,730 yrs. Carbon 14 30 sec. Rhodium 106 30 sec. Rhodium 106 4.5 billion yrs. Uranium 238 4.5 billion yrs. Uranium 238

20. Half-Life

21. Terminology of Radioactivity Decay series – the series of steps by which a radioactive nucleus decays into a non-radioactive nucleus.Decay series – the series of steps by which a radioactive nucleus decays into a non-radioactive nucleus. Transmutation – the changing from one element into another after a nuclear reaction has taken place.Transmutation – the changing from one element into another after a nuclear reaction has taken place. Artificial transmutation – the changing from one type of element into another through science (man).Artificial transmutation – the changing from one type of element into another through science (man).

22. Decay Series

23. Transmutation Where one element changes into another as a result of changes in the nucleus (beta decay) Where one element changes into another as a result of changes in the nucleus (beta decay)

24. Ernest Rutherford Produced the first artificial transmutationProduced the first artificial transmutation A particle accelerator uses magnets and electric fields to speed up particlesA particle accelerator uses magnets and electric fields to speed up particles

26. Now the fun begins!!

27. Nuclear Fission Splitting of an atomic nucleus into 2 smaller nuclei of approximately equal massSplitting of an atomic nucleus into 2 smaller nuclei of approximately equal mass

28. Chain Reaction Nuclear Chain Reaction – billions of fissions reactions take place every second. The energy produced is extreme and causes a nuclear explosion (the atom bomb).

29. Nuclear Power Plants In a nuclear chain reaction billions of fission reactions may take place each second Ex: current operating nuclear plants use fission to create energy in the form of heat and then transferred into electricity

30. Atom Bomb Einstein hated that people used his discovery for this…

32. Nuclear Fusion Joining of 2 atomic nuclei of smaller mass to form a single nucleus of a larger massJoining of 2 atomic nuclei of smaller mass to form a single nucleus of a larger mass Temperature must be well over a million degrees CelsiusTemperature must be well over a million degrees Celsius Fusion produces less radioactive wasteFusion produces less radioactive waste Ex: the sunEx: the sun

34. Tools used to detect radiation Electroscope – a simple device that consists of a metal rod with two thin metal leaves at one end.Electroscope – a simple device that consists of a metal rod with two thin metal leaves at one end. Geiger counter – developed in 1928. Consists of a tube filled with a gas such as argon at reduced pressure. Makes a clicking noise each time the nucleus releases a particle or energy.Geiger counter – developed in 1928. Consists of a tube filled with a gas such as argon at reduced pressure. Makes a clicking noise each time the nucleus releases a particle or energy.

35. Pictures of the tools used… Bubble chamber electroscope Cloud chamber Geiger counter

36. Radioactivity uses Radioisotopes – can be used to find leaks or weak spots in metal pipes. Can also be used as a tracer in humans to track blood flow.Radioisotopes – can be used to find leaks or weak spots in metal pipes. Can also be used as a tracer in humans to track blood flow. Radiation – can also be used to destroy unhealthy cells that cause cancer. This treatment is called radiation therapy.Radiation – can also be used to destroy unhealthy cells that cause cancer. This treatment is called radiation therapy.

37. Dangers of radiation The same radiation that kills cancer can also cause cancer.The same radiation that kills cancer can also cause cancer. Radiation sickness – reddening of skin, drop in white blood cells, nausea, fatigue, and loss of hair.Radiation sickness – reddening of skin, drop in white blood cells, nausea, fatigue, and loss of hair. We are constantly exposed to some radiation through cosmic rays, microwaves, cell phones, x- rays, etc…We are constantly exposed to some radiation through cosmic rays, microwaves, cell phones, x- rays, etc…

38. Radiation Sickness NauseaNausea FatigueFatigue Loss of hairLoss of hair Cause of Marie Curie’s death!Cause of Marie Curie’s death!

39. Radioactive comics. Sooo…that’s how Rudolph got his red nose.

42. Chernobyl http://www.youtube.com/watch?v=3u _8frR0IpE

43. What caused the Chernobyl Disaster? In the early morning of 26 April 1986, one of the four reactors at the Chernobyl nuclear power station ran out of control while engineers were running safety tests. Within four seconds, a power surge of 100 times normal output led to a violent explosion and fire. The 1,000 tonne concrete top of the reactor building was blown off and huge chunks of blazing, radioactive material were blasted into the air like a volcanic explosion. The reactor burned furiously and highly radioactive debris was scattered around and inside the reactor building.

45. What caused the Chernobyl Disaster? The reactor burned for a week, spewing out radiation, and was eventually put out by helicopters dumping tonnes of sand, and fire fighters and site works fighting the blaze. Hundreds of thousands of people, many of them soldiers, were drafted in to clean up the site. They had very little in the way of protective clothing and were only allowed into the reactor building for 90 seconds at a time. They were called the ‘liquidators’. The clean-up work continued for two years as the entire reactor building was sealed in a huge concrete tomb-like structure known as the Sarcophagus.

46. The monument to the “Liquidators ” who lost their lives putting out the fires

48. Where is Chernobyl? Chernobyl is about 1,500 miles from Britain, 60 miles north of Kiev, capital of the Ukraine in Eastern Europe. Now an independent country, in 1986 the Ukraine was part of the Soviet Union. Just to the north is the international border with Belarus, then also part of the Soviet Union. Belarus was to be the country worst affected by the disaster. The nuclear power station was Soviet designed and built.

50. What happened to those nearby? Direct casualties of the explosion were rushed off to hospitals as far away as Moscow. Then it became clear that because of the intense radioactive fallout, all the surrounding population would have to be evacuated – 14,000 people. Police surrounded Pripyat, the nearest town (2.5km away), set up road blocks and prepared to deal with any panic.

51. On Sunday 27 April, at 1.50pm, local radio announced the start of a mass evacuation. At 2pm, 1,100 buses began to pick up the 40,000 residents. Almost all belongings had to be left behind. Sunday lunches were left on tables, pets and livestock abandoned. By 4.20pm the town was empty. In all, more than 110,000 men, women and children were evacuated from surrounding areas.

52. Illnesses and deaths Immediately after the accident about 30 people died but this was just the beginning of the deaths, illnesses and changes to DNA Although it is impossible to say with certainty that a particular cancer has a particular cause, statistics imply that the accident at Chernobyl has had a catastrophic effect on the populations of nearby areas. There had been up to the year 2002 about 4,000 cases of thyroid cancer reported in children and adolescents who were exposed at the time of the accident, and more cases can be expected during the next decades.