2003 Virginia SOLs
Motivation for Learning
List the answers as given by students to the following questions on the board or a transparency:
How many useful uses of radiation can you name? (x-rays, food irradiation to eliminate bacteria, smoke alarms, oil discovery, radio waves, TV waves, microwaves, light, etc.).
Can radiation exposure be totally avoided? (no, there is radiation coming from outer space and from material all around us. Our radiation exposure is higher when we fly in airplanes.)
What are some unusual sources of radiation? (smoke alarms, concrete walls, microwaves, TVs)
When is radiation exposure a risk worth taking? (for health reasons: x-rays for teeth and tuberculosis, food irradiation)
Every day we are exposed to radiation. Radiation is the process of emitting energy in the form of particles or waves. Some forms of radiation are more energetic (and therefore more potentially harmful) than others. The only difference between different waves of the electromagnetic spectrum is the frequency (or amount of energy) of each wave. X-rays are much more energetic than radio waves. Exposure to energetic waves like x-rays should be limited. However, people permit x-ray radiation exposure in order to locate a broken bone or identify medical problems. Some forms of radiation exposure are unavoidable, such as cosmic radiation from outer space.
The basic unit for measuring radiation received is the rad (roentgen absorbed dose). One rad equals the absorption of 100 ergs (erg--a small but measurable amount of energy) in every gram of tissue exposed to radiation. To show biological risk, rads are converted to rems. The rem (roentgen equivalent man) is adjusted to take into account the type of radiation absorbed and the likelihood of damage from the different types of radiation. Exposures are normally in fractions of a rem, so the commonly used unit of exposure is the millirem (mrem). 1 rem = 1000 millirem. Most scientists estimate that the average person in the United States receives a dose of about 360 millirem of radiation per year.
See the two sites given in the Extensions for considerable additional information about nuclear radiation, reactors, radioactive waste, etc. They have lesson plans for teachers.
To print out the Student Copy only, click here.
To print out the Activity Sheet only, click here.
Every day each of us is exposed to radiation: ultraviolet light from the sun, x-rays, warmth from other people, and a vast spectrum of electromagnetic waves. Some of these are very high energy and potentially dangerous. Exposure to these should be limited. Some radiation exposure is unavoidable, such as the cosmic radiation from space. Some radiation is permitted for medical or health benefits.
Use the information below to calculate your exposure to radiation for the past calendar year. This is only an estimated value.
Students with Special Needs
Each student should be able to participate in this activity.
Click here for further information on laboratories with students with special needs.