Transcript Chapter 25.4 Radiation in your life
Chapter 25 Nuclear Chemistry 25.4 Radiation in Your Life
Chemistry
Today we are learning to:-
1. Identify 3 devices used to detect radiation 2. Describe how radioisotopes are used in medicine
25.4
Radiation in Your Life
In a smoke detector, radiation from the Americium nuclei ionizes the nitrogen and oxygen in smoke-free air, allowing a current to flow. When smoke particles get in the way, a drop in current is detected by an electronic circuit, causing it to sound an alarm. You will learn about some of the other practical uses of radiation.
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Radiation in your life
Detecting Radiation Radiation emitted by radioisotopes is called
ionizing radiation
It has enough energy to knock electrons off some atoms of the bombarded substance to produce ions. Geiger counters , scintillation counters , and film badges are commonly used to detect radiation.
25.4
Detecting Radiation
Detecting Radiation
Radiation in your life
Radiation can produce ions, which can then be detected, or it can expose a photographic plate and produce images.
25.4
Detecting Radiation
Detecting Radiation
Radiation in your life
1. Geiger Counter : uses a gas-filled metal tube to detect radiation. It is usually used for detecting beta radiation
25.4
Detecting Radiation
Detecting Radiation
Radiation in your life
2. Scintillation Counter : uses a phosphor-coated surface to detect radiation. It can detect all types of ionizing radiation
25.4
Detecting Radiation
Detecting Radiation
Radiation in your life
3. Film Badge : consists of several layers of photographic film covered with black lightproof paper, all encased in a plastic or metal holder.
25.4
Using Radiation
Detecting Radiation Radiation in your life
Neutron activation analysis
is a procedure used to detect trace amounts of elements in samples.
Neutron activation analysis is used by museums to detect art forgeries, and by crime laboratories to analyze gunpowder residues.
25.4
Using Radiation
Detecting Radiation Radiation in your life
Radioisotopes in medicine Radioisotopes can be used to diagnose medical problems and, in some cases, to treat diseases.
Iodine-131 is used to detect thyroid gland problems
25.4 Section Quiz.
1. Ionizing radiation can remove _______ from atoms.
a. protons b. neutrons c. positrons d. electrons.
25.4 Section Quiz.
2. Which of the following is NOT a device used to detect radiation?
a. Geiger counter b. scintillation counter c. film badge d. radioisotope
25.4 Section Quiz.
3. Choose the correct words for the space. When a tumor is treated by radiation, more cancer cells than normal cells are killed because cancer cells ____________ than normal cells. a. are more susceptible to damage because they grow faster b. absorb more radiation because they are larger c. grow slower d. are smaller
25.4 Section Quiz.
– 4.
How do scientists detect thyroid problems?
• with teletherapy • by neutron activation analysis • using an iodine-131 tracer • using a radioisotope sealed in a gold tube
• • • •
2.3 Vocabulary
25.3 Vocabulary
Fission:
the splitting of a nucleus into smaller fragments
Neutron moderation:
process of slowing down neutrons do they will be absorbed by nuclei.
Neutron absorption:
process of decreasing the number of slow moving neutrons by using control rods
Fusion:
when light nuclei fuse together to form a single nuclei • • • • • 25.4 Vocabulary
Ionizing Radiation:
knocks electrons of atoms to produce ions
Geiger Counter Scintillation Counter Film badge Neutron activation analysis:
used to detect trace amounts of elements in a sample