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Search>Learning Exercise Results> Radioactive Decay Lesson

Title:
Material:
Description:
This lesson attempts to teach how radioactive decay works. A two question warm-up will be ready for students as class begins. A web demo showing radioactive decay will be given and transition into an overhead lecture on decay.
Next, a lab will model the rate of decay of radioactive isotopes using a penny model. Students will work in groups to complete the lab and then present their findings to the class on a white board.
Students will be given a short quiz on the events in the lesson which will be used for individual assessment.
Course: Nuclear Processes

Submitted by:
David Ureno
June 30, 2006

Exercise

Sequence of Activities:

1) After bell Rings, lights go off, video plays:
http://www.jpl.nasa.gov/videos/mars/viking-062206/viking-062206.mp4
Announce beginning of Nuclear Processes unit, Talk about energy briefly and
place the two-question prompt on the over head.
(questions should be generic math problems that are relevant to half life
concept e.g what is half of half of half of half of 800?)

Students: Will be attempting to solve the two items on the overhead and asking
questions
have finished with the two questions, finally announcing the outline of the days
events.

2) PowerPoint and Web demonstration of radioactive decay
Students: actively listening to the web demo and asking question as well as
Teacher: Making transition from the two-question prompt to the lecture, and
explaining how decay half life proceeds with time

(should be specific to your class's achievement level - include vocabulary and
definitions, possibly alpha, beta, and gamma radiation and even decay equations
Students: Taking notes in composition book, asking questions.
Teacher: presenting new material, monitoring students for participation and
attention.

4) Lab instructions/ pass out group hand outs
Students: Receiving hand-out and asking lab questions if confused
Teacher: Providing instruction on the lab, asking for questions, putting
students in groups, moving seats to such that they are conducive to group work,

5) Penny lab
Students: Working in groups on the penny lab
keeping them involved.

6) Group presentations

Students: Showing their graph and presenting their ideas and/or solution to an
assigned problem
Teacher: giving positive feedback, offering encouragement, using the
presentation to facilitatereview of the material.

7) Final assessment quiz (please tailor the quiz to your students - rewrite if
necessary)
Students: going back to their seats, and taking the quiz
Teacher: quietly observing

Each question is ½ point

Part 1Instructions: fill in the blank with the best fitting term from todays
lesson.
1. The time required for one-half of a radioactive isotope to decay into its
products is _______________.

2. A series of nuclear reactions that begins with an unstable nucleus and
results in the formation of a stable nucleus is _______________.

3. A radioactive isotope is also known as an unstable ____________ atom.

4. The final decayed atom is called the stable _____________ atom.

5. If a sample of radioactive isotope had half of its atoms decay in 200 years,
how long would it take for 100 atoms of the same radioactive isotope to decay to
25 atoms? Show work

6. A sample of 800 Carbon-14 atoms, a radioactive isotope, has decayed to 200
atoms over a given period of time. If each time a half-life occurs ½ of the
atoms decay, how many half-life periods have occurred?

7. What is the half life of carbon-14 if it took 17,190 years for 800 atoms to
decay to 200 atoms?

8. A Radioactive isotope has a half life of 10 seconds. How many atoms will
remain after 40 seconds of a sample of 400 atoms?

• High School

Topics

CA- California K-12 Academic Content Standards

 Chemistry, 9-12, Nuclear Processes

 Concept 11: Nuclear processes are those in which an atomic nucleus changes, including radioactive decay of naturally occurring and human-made isotopes, nuclear fission, and nuclear fusion. As a basis for understanding this concept:

Standard f: Students know how to calculate the amount of a radioactive substance remaining after an integral number of half lives have passed.

CA- CCTC Level II Technology Standards
Standard 16: Using Technology to Support Student Learning

Element: 16(a) Each participating teacher communicates through a variety of electronic media.
Element : 16(e) Each participating teacher uses technology in lessons to increase students ability to plan, locate, evaluate, select, and use information to solve problems and draw conclusions. He/she creates or makes use of learning environments that promote effective use of technology aligned with the curriculum inside the classroo

Learning Objectives

Objective(s):
Students will be able to

1) Describe how radioactive isotopes decay with time

2) Calculate the amount of a radioactive substance remaining after an integral number of half lives have passed

• Individual
• Student-centered
• Teacher-centered
• Team

Technical Notes

Instructional Materials: