This lesson has been designed to help inform third through fifth grade students about radon gas, which has been found at high levels in many homes throughout Delaware. The east coast in general has higher than average levels of radon, although amounts vary from house to house. Knowing your neighbor’s level of radon does not tell you anything about your own level of radon; each house needs to be tested individually to know if it contains higher than acceptable radon gas levels (mitigation is suggested if amounts are above 4 picocuries per liter, written as 4 pCi/l). Because radon is believed to be the second leading cause of lung cancer in the United States, contributing to an estimated 14,000 deaths per year, it is an important topic to include in the elementary science curriculum.

According to the science content standards from New Directions: Delaware First in Education, by the end of third grade students are expected to meet Standard 2: Materials and their Properties, and understand that "materials exist in one of three states—solid, liquid, or gas." Radon gas should be introduced and defined as a radioactive (harmful) gas caused by the natural breakdown of uranium, common in some rocks and soil.

By the end of fifth grade, students should meet Standard 6: Life Processes, and understand that "technological advances in medicine, the development of various safety devices and protective equipment. . . have helped in the diagnosis and treatment of illness and have reduced the number of damaging and life threatening injuries." It is important for students to know that one can easily, and inexpensively, test for radon gas using either short-term or long-term tests. If results come back high (over 4 pCi/l), remediation can take place in the form of sealing cracks in the foundation and floors where radon gas enters the home, and by venting radon gas out of the house through a process known as sub-slab depressurization. The latter process involves the installation of a pipe through the lowest floor (usually hidden between walls), creating a change in pressure whereby the radon gas is "sucked up" through the pipe and vented out through the roof of the house.

By the end of third grade students should also meet Standard 8: Ecology and know that "the earth consists of living and nonliving things. All living things interact with each other and the nonliving parts of their surrounding—air, water, soil, and sun." In this case, human beings interact with the inert gas known as radon, which can cause lung cancer. By the end of fifth grade, students are expected to know that "pollution and human activities can change the environment and adversely affect the health and survival of humans and other species." In this case, the air pollution is naturally caused. This point will need to be stressed to children, who commonly believe that radon is radioactive waste material from nuclear power plants. Students can be reassured that some newer houses in parts of Delaware are now being built with sub-slab depressurization to prevent the build-up of radon gas, and its ensuing health problems. For homes that do not have this built-in device, testing and mitigation are important.

1. Grade Levels: Grades 3 through 5

2. Overview: Students in grades 3 through 5 will learn about radon gas through a single 30-minute lesson, then will draw pictures illustrating their understanding.

3. Purpose: The purposes of this lesson are: 1) to educate children about the health risks of radon, and 2) for students to share this understanding with their families.

4. Objectives: Students will demonstrate their understanding of what radon gas is, where it comes from, why it is a health problem, and how to reduce it.

5. Materials: Balloon; 8 ½ x 11 in. white tag board; markers; written pretest and posttest on knowledge of radon; sample radon-testing kit; "radon stickers"; fact sheet on radon for parents; coupons for ordering test kits; poster of child’s drawing of radon

6. Activities:

1. After a brief pretest (included), show poster or overhead created from Master #1, to outline the discussion to follow. Ask students what, if anything, they know about radon gas. Use overheads or posters created from the provided masters to stimulate discussion on:

1. What radon gas is:

• it is a naturally occurring, radioactive gas that you can’t see, smell, or taste (see master #2)

• inflate a balloon to demonstrate that some gases are invisible, without a scent or taste. The concentration of carbon dioxide is high inside the walls of the balloon, but once the balloon is deflated, the gas disperses, spreading out throughout the air (just as invisible radon gas can accumulate within a house, but disperses to harmless levels when it is outside in nature).

• the term radioactivity can be defined for the earlier grades as simply "deadly, or harmful to one’s health; cancer-causing"; for the fifth graders the term can be defined more scientifically as "emitting harmful rays due to the disintegration of the nuclei of atoms."

1. Where radon gas comes from:

• Radon gas comes from the soil and rocks underneath some homes. Students should understand that this is a natural process of the decay of uranium, present in varying degrees in all rocks. Radon gas is not the waste product of nuclear power plants (as many elementary students believe).

• Ask students to predict how the gas enters the home (primarily through cracks and holes in the lowest floor of the house).

• Using the overhead or poster #3 as a guide, show how a house serves to contain radon gas (much as a balloon contains carbon dioxide). The amount of radon can build up to dangerous levels. The radon gas produced outside in nature is free to disperse, producing negligible risk to humans.

1. Why radon is a health risk:

• Use master #4 to illustrate that breathing radon gas for many years may cause lung cancer (in fact it is believed to be the #2 cause of lung cancer, second only to smoking). Here the lesson can be linked to what students already know about smoking as a cause of lung cancer.

• Radon is estimated to cause 14,000 deaths in the U.S. per year.

• Furthermore, the risks of damage due to radon increase if you smoke (see Questions Commonly Asked by Students for a more in-depth discussion of this topic).

1. How we can reduce the risk of radon (see master #5)

• First, students should become educated about radon, for example through this lesson; they can then take this knowledge home with them, and talk to their families about the known risks of radon gas. Students should be given a fact sheet (provided) to take home to further stimulate discussion.

• In an effort to show students that this is a serious problem that fortunately can be avoided, testing for radon should be thoroughly described. A sample kit circulated around the room will help foster discussion about how to conduct a short-term test. A canister or envelope containing charcoal is suspended about 2 to 6 feet from the middle of the lowest floor that is commonly used in the home. After 4 to 7 days, the kit is mailed in, and results are returned within several weeks. If the results show that the home contains high amounts of radon (above 4 pCi/l), remediation in the form of sealing cracks and venting the gas out of the home is recommended.

• The radon fact sheet has a toll-free number for concerned parents or guardians to call to find out more about radon, and to find out recommended names of mitigators (people who can fix the problem).

• A coupon for ordering an inexpensive testing kit (included) should be handed out to every student.

1. After answering students’ questions about radon, have them "draw a picture for someone who doesn’t know anything about radon what it is, where it comes from, why it is a problem, or how to reduce it." After this project has been completed, show students the poster of the winning drawing of radon, that is included with this packet. During drawing time, circulate and answer any remaining questions.

1. Hand out "radon stickers" that can be worn home to further increase the chances that parents or guardians will discuss the problems of radon with their children.

7. Assessment: The same 8-item true/false quiz as the pretest, in a different random order, will be used as a posttest (included) to assess gains in understanding about radon following instruction. Pilot results on 271 students in 14 classrooms (including 5 classrooms for children with learning differences) indicate average gains of 2 points.

8. Further Experiments: Because many students wonder whether their own schools contain radon gas, the sample testing kit can be used to actually measure the amount of radon gas in the classroom. Students will learn from hands-on experience how simple it is to conduct a radon test. They should be reassured that schools in Delaware have all been tested for radon. If other classrooms use this lesson plan, students can graph the different results, and see if the levels of radon gas vary from classroom to classroom, and from floor to floor (because of the nature of the entry of radon gas, the lowest levels can be expected on the highest floors).

Questions Commonly Asked by Students (and sample answers):

Q: Where should you conduct the test?

Q: What kind of rocks and soil give off radon?