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NUCLEAR CONCEPTS in EARTH SCIENCE & PHYSICAL SCIENCE KENTUCKY CORE CONTENT for ASSESSMENT in High School Science BIG IDEA: EARTH AND THE UNIVERSE (Earth/Space Science ) SC-HS-2.3.3 Students will explain the origin of heavy elements in planetary objects (planets & stars)
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NUCLEAR CONCEPTS in EARTH SCIENCE & PHYSICAL SCIENCE
SC-HS-2.3.3 Students will explain the origin of heavy elements in planetary objects (planets & stars)
SC-HS-2.3.4 Students will understand that stars generate energy from nuclear fusion reactions that create successively heavier chemical elements.
SC-HS-2.3.6 Students will compare the limitations/ benefits of various techniques for estimating geologic time (radioactive dating, observing rock sequences, and comparing fossils).
SC-HS-4.6.11 Students will: • explain the difference between alpha and beta decay, fission, and fusion; • identify the relationship between nuclear reactions and energy.
SC-HS-4.6.12 Students will understand that the forces that hold the nucleus together, at nuclear distances, are usually stronger than the forces that would make it fly apart.
Objective 1 Describe the structure and use of the : • electroscope • Geiger counter • cloud chamber • photographic film
KEY TERMS • electroscope • Geiger counter • cloud chamber • radioisotope • tracer
The Gold Leaf Electroscope • When an electroscope is charged, the gold leaf sticks out, because the charges on the gold repel like charges on the metal rod. • When a radioactive source comes near, the air is ionized, and starts to conduct electricity. This means that the charge can "leak" away, the electroscope discharges and the gold leaf falls.
Geiger Counter • This is actually a Geiger-Müller tube with some form of counter attached, which usually tells us the number of particles detected per minute ("counts per minute"). • GM tubes work using the ionizing effect of radioactivity.
Cloud Chamber • The chamber contains a supersaturated vapor which condenses into droplets when disturbed and ionized by the passage of a particle. • The droplets form a trail in the chamber.
Photographic Film • In 1896, Henri Becquerel discovered that uranium compounds would darken a photographic plate, even if the plate were wrapped up so that no light could get in. • The amount of “fogging” or darkening is determined by how much radiation strikes the film.
Photographic Film • Workers in the nuclear industry wear "film badges" which are then developed. • This allows for the measurement of the dose that each worker has received.
Objective 2 Describe the use of radioisotopes in: • studying organisms • diagnosing and treating disease • sterilizing food • monitoring industrial processes
Radioactive Dating • Animals and plants have a known proportion of carbon-14 in their tissues. • When they die, the amount of C-14 goes down at a known rate. • Since C-14 has a half-life of about 5700 years, the age of ancient organic materials can be found by measuring the amount of C-14 that is left.
Radioactive Tracers • Radioisotopes are frequently used as tracers whose pathways through the steps of chemical reactions may be traced. • These may be used for medical purposes such as checking for blockages or circulatory problems.
Cancer Treatments • Because gamma rays can kill living cells, they are used to kill cancer cells without having to resort to difficult surgery. • This is called radiation therapy and works because cancer cells cannot repair themselves when damaged as healthy cells can.
Sterilizing • Even after it has been packaged, gamma rays can be used to kill bacteria, mould and insects in food. • This process prolongs the shelf-life of the food. • Gamma rays are also used to sterilize hospital equipment, especially plastic syringes that would be damaged if heated
Industrial Processes • Radioisotopes may be used in industry to detect leaking pipes. To do this, a small amount is injected into the pipe. It is then detected with a GM counter above ground. • Checking welds: a gamma source is placed on one side of the welded metal and a photographic film on the other side. Weak points or air bubbles will show up on the film, like an X-ray.
WORKSHEETS • Estimate Your Personal Radiation Dose • Atomic Crossword (NRC website) • Test Your Nuclear Knowledge Quiz (NRC website)
LAB ACTIVITY • Radiation and Shielding
RESEARCH • Nuclear Weapons • Nuclear Power Plants
MEDIA ITEMS • Videos: A Look at Radiation and Managing Radiation ( a free kit from The National Safety Council: http://www.nsc.org/issues/radisafe.htm) • Website of Nuclear Regulatory Commission: http://www.nrc.gov/reading-rm/basic-ref/students.html (student activities)
GOING FURTHER • Obtain a radon test kit and test your home for the presence of radon gas. (These may be obtained free-of-charge from some local health departments.)
GOING FURTHER • Observe radiation flashes by looking at a Fiestaware plate through a magnifying glass in a totally dark room. (First allow a few minutes for your eyes to adjust to the darkness.)