Science 10Chapter 7 - Radiation

7.3 EFFECTS OF RADIATION

5 min, in groups,

List as many types of radiation that you can think of

Atoms of radioactive isotopes are everywhere. There is radiation in our body, the earths water, soil and upper atmosphere. This radiation is called natural background radiation.

Short wavelengths have enough energy to knock electrons from the atoms that they hit. This can deform cells and cause them to stop working properly.

Ultra-violet and X-Ray radiation has long-term effects, which include cancer and mutations in cells.

Cancer is caused by a mutation in the cell. This mutation allows the cells to keep on reproducing and never stop. Doctors can also use radiation to slow down the spread of cancerous cells.

Chemotherapy – inject chemicals into your body that slow down the spread of cancer

Radiation therapy – use X-rays and gamma rays to slow down the spread of cancer.

Technological applications of radiation

  • home (e.g. microwave ovens, smoke detectors, TV)
  • medical (e.g. X rays, cancer therapy, nuclear medicine)
  • industry (e.g. structural flaw detection)
  • scientific (e.g. carbon dating)
  • recreational (e.g. tanning machines)

X-Ray image of your lung

X-Ray image of a clavicle, shoulder, that has been broken and fixed with metal screws and pins

Pelvis

Broken arm

A computerized axial tomography scan or CAT scan is a procedure which uses a computer for combining many x-ray images into cross-sectional views of the internal organs of the body, including the brain. CAT scans are used to image both normal and abnormal structures in the body and can also be used to help guide the placement of instruments or treatments.

7.4 NUCLEAR ENERGY

Nuclear Fission

-the process by which a large nucleus splits into pieces, this produces large amounts of energy and causes a chain reaction to occur. The energy comes from the equation, E = mc2.

Nuclear Reactors

-a structure that is designed to control the release of the heat energy from a chain reaction. If too much heat energy is being released then the reactor is said to “meltdown”, which destroys the reactor.

Problems

-isotopes can leak from the reactor

-no good way of disposing of the radioactive byproducts

-the reactors must be destroyed and re-built every 30 years

Nuclear Fusion

-small nuclei are fused together to make a large nuclei. This process produces a lot of heat energy by the conversion of mass to energy.

Example, Hydrogen Fusion

-At a temperature of 100 000 000ºC, hydrogen nuclei move fast enough so that when they collide they fuse together and start a reaction. The hydrogen bomb is a device that is able to produce enough heat to cause hydrogen fusion.

Group 1 Electromagnetic Radiation, pg 134-135

Group 2 Radiation from Atoms, pg 136 , 138

Group 3 Isotopes, pg 139

Group 4 Effects of radiation on Living Organisms

Hazards, Protection Applications, pg 145-149

Group 5 Nuclear Fission and Nuclear Fusion

Group 6 Nuclear Reactors and problems pg 153-154