Teaching the Concept of Half-Life

Teaching the Concept of Half-Life

Lesson 1: Radioactive Decay Bohr-Rutherford model of atom, isotopes – review Alpha, Beta and Gamma Decay

Lesson 2: Measuring the rate of Radioactive Decay Process Half-Life Aplication of Half-Life: Carbon Dating

Lesson 3: Nuclear Fission and Nuclear Power Generation Mass Energy Equivalence Nuclear Fuel Chain Reactions

Lesson 4: Nuclear Fusion Nuclear Stability Stellar Fusion Magnetic Confinement Fusion

Lesson 5: Applications of Nuclear Technology Candu Reactors, Waste disposal Medical applications of Radioisotopes

Lesson 6: Nuclear Energy : Benefits and Hazards

Lesson Sequence

Overall:

D3. demonstrate an understanding of work, efficiency, power, gravitational potential energy, kinetic energy, nuclear energy, and thermal energy and its transfer (heat).

Specific:

D1.2 assess, on the basis of research, how technologies related to nuclear, thermal, or geothermal energy affect society and the environment (e.g., thermal regulating units, radiopharmaceuticals, dry-steam power plants, ground-source heat pumps) [IP, PR, AI, C]

D2.1 use appropriate terminology related to energy transformations, including, but not limited to: mechanical energy, gravitational potential energy, kinetic energy, work, power, fission, fusion, heat, heat capacity, temperature, and latent heat [C]

D2.7 compare and contrast the input energy, useful output energy, and per cent efficiency of selected energy generation methods (e.g., hydroelectric, thermal, geothermal, nuclear fission, nuclear fusion, wind, solar) [AI, C]

D2.8 investigate the relationship between the concepts of conservation of mass and conservation of energy, and solve problems using the mass– energy equivalence [PR, AI]

D3.6 describe and compare nuclear fission and nuclear fusion

D3.9 identify and describe the structure of common nuclear isotopes (e.g., hydrogen, deuterium, tritium)

D3.10 compare the characteristics of (e.g., mass, charge, speed, penetrating power, ionizing ability) and safety precautions related to alpha particles, beta particles, and gamma rays

D3.12 explain the energy transformations that occur within a nuclear power plant, with reference to the laws of thermodynamics (e.g. nuclear fission results in the liberation of energy, which is converted into thermal energy; the thermal energy is converted into electrical energy and waste heat, using a steam turbine)

Curriculum Expectations for Energy and Society Unit

After the earthquake and tsunami hit Japan and its nuclear plants in 2011, the world held its breath

These headlines were almost in all newspapers and television stations

Do you know how to measure the rate of radioactive decay of radiocative elements?

My guess is you do not.

Let us learn today how to do it!

• What is the risk from Caesium-137 and Iodine -131 at Fukushima? • How long does it take for radioactive atoms to decay?

Introduction to Half-Life

• D3.11 explain radioactive half-life for a given radioisotope, and describe its applications and their consequences

Specific Curriculum expectations for the lesson:

• Virtual Lab: Measuring the Rate of Radioactive Decay http://glencoe.mcgraw-hill.com/sites/dl/free/0078693896/280405/E18.html

Students will use an inquiry based approach to investigate the meaning of radioactive half-life

Students interactively learn that radioactive materials decay at different rates

Half- Life: Teaching Strategy 1: Inquiry Based Learning:

The average length of time it takes a radioactive material to decay to half of its original mass

What is Half–Life?

The half-life of any given isotope is actually an average time for a particular parent atom to decay to its daughter atom

The larger the sample size, the more accurately a material decays according to its half-life

Half-Life Equation:

A - massA0 - initial sample masst - timeh – half-life

What is Half–Life?

• While standing, each of students will be flipping a

penny

• Each time they flip, one half-life will have passed

• If a penny lands on heads, the student is regarded as radioactive, has decayed and needs to sit

• If a penny lands on tails, the student have not decayed (remain standing)

• After each half-life , a teacher should count students who stand and plot data on a the overhead

• Students will be asked to predict what will happen to the numbers of remaining parent isotopes

Students will participate in a demonstration that visually illustrates the concept of half-life

Half- Life: Teaching Strategy 2: Demonstration

Students will learn what carbon dating is and why Carbon -14 is a useful isotope for dating fossils and

other archeological objects Carbon 14 Decay: http://www.youtube.com/watch?v=81dWTeregEA

Carbon Dating: http://www.youtube.com/watch?v=31P9pcPStg&feature=related

Short Dicussion: Student will share what they understood from these videos

Half-Life: Teaching Strategy 3: Application of Half-Life: Introduction to Carbon Dating –Videos and Discussion

• Students will find out the age of five different „fossils” a bag represents a fossil and beads inside the bag

–> atoms

• Students need to : use half-life properties of isotopes to determine the

age of different fossils

count the number of parent and daughter isotope atoms in each bag

determine how many half-lives the isotope has gone through

determine the age of the fossil

This hands-on activity allows students to gain a better understanding of how scientists use isotopes to determine the age of fossils and

archeological objects

Half-Life Teaching Strategy 4: Radiometric dating activity – What is the

age of the fossil?

Potential Student Difficulty Solution

Show your students a demonstration with popping popcorn

Explain that when popcorn kernels are poured into popcorn popper, it is impossible to predict which kernel pops first

When they are removed from the

popper they are not kernels any more. They have been transformed and changed forever

Understanding that radioactive decay is a

spontaneous process that involves irreversible

transformation of one element into another

Potential Student Difficulty

Realizing the difference between radioactivity and radioactive decay

Solution

Radioactivity

refers to the particles which are emitted from nuclei as a result of nuclear instability

Radioactive decay

the process by which a radioactive atom’s nucleus breaks apart and forms different atoms

Show your student the following poster and explain using pictures what the difference is

Potential Student Difficulty Solution

Understanding that nuclei do not disappear when they decay

Show students an animationhttp://www.youtube.com/watch?v=o-9yt7OAYmE

Potential Student Difficulty Solution

Wrongly interpreting half-

life as half the time for the

radioactivity to disappear

Use demonstrations such as a coin toss or M&M’s to help students understand the concept

Depict the results of these demonstrations as a curve of an exponential decay function

Analyze with student the shape and changes in number of isotopes

Major safety concern should be an appropriate Internet conduct as the virtual lab is done on-line

Enough space in the classroom should be provided for students when they do their radiometric dating activity

The classroom should be free from clutter when students circulate between stations while doing radiometric dating activity

Safety Considerations

Practical Applications of Radioactive Decay

• MEDICINEdiagnostic medical imaging to detect tumors, bone fracture

(medical and dental X-ray images, SPECT, PET, MRI)

radionuclide therapy (RNT – bombarding dividing harmful cell with radiation)• EARTH SCIENCES – using C-14 for dating of geological

specimens • NUCLEAR PHYSICS – nuclear energy production

Differentiated Assesment

Assssment will be ongoing

Multiple intelligences will be taken into account while assessing students

Students will be assessed based on:

Written laboratory reports (formative and summative) Classroom discussions / small group discussions Oral responses and presentations Tests/ quizzes Problem solving assignments (numerical and non-numerical) Research assignments on applications of nucelar technology - students will be

given a chance to choose a topic and a method they would like to prepare the concept: poster, newspaper article, song, Power Point Presentation, drama, podcast, game, photo journal, demonstration, jigsaw, oral presentation

Exit tickets will be taken to check students’ understanding of delivered material

Keeping in mind a lesson on Half-Life- assessment will be based on: written lab report (formative) and classroom discussion

Students with IEP• Activities, assignments, laboratory practice, tests, quizzes

will be modified and designed to meet specific learning needs

ELL students• Will be given more time to finish their assignments• Will be provided with teacher assistance whenever possible• Will be given a chance to seat beside someone who speaks

their first language/ who speaks English but is eager to provide support

• Students will receive (in advance) a lesson outline with important words essential to do a classroom activity, lab reports

Accomodations for students with special needs

• Virtual Lab on radioactive decay (alpha decay)• http://phet.colorado.edu/en/simulation/alpha-decay

• Radioactive Dating: Looking at Half-Lives Using M&Ms• http://serc.carleton.edu/sp/mnstep/activities/34884.html

• Using Popcorn to Simulate Radioactive Decay• http://serc.carleton.edu/quantskills/activities/popcorn.html

• Activities for teaching fundamental concepts of nuclear energy and related topics (a variety of activities)• http://www.uraweb.org/reports/skoog.pdf

• Radioactive Dating Game:• http://phet.colorado.edu/en/simulation/radioactive-dating-game

• Nuclear Fission Simulation:• http://phet.colorado.edu/en/simulation/nuclear-fission

• Class as an Artifact: A Radioisotope Dating Activity:• http://www.acad.carleton.edu/curricular/BIOL/classes/bio302/pages/ClassFossil.ht

ml

Suggestions for other student labs/activities related to nucelar reactions

Students misconceptions: http://www.furryelephant.com/content/radioactivity/teaching-learning/radioactivity-misconceptions/http://serc.carleton.edu/quantskills/methods/quantlit/RadDecay.html

Demonstration of radioactive decay using pennieshttp://serc.carleton.edu/quantskills/activities/PennyDecay.html

Radiometric Dating Activityhttp://www.acad.carleton.edu/curricular/BIOL/classes/bio302/pages/half-life.html

Information about half-life - half-lives for various radioisotopes:http://theenergylibrary.com/node/11798

Physics 11 - textbook – definition and explanation of half-life, definition of radioactive decay

DiGiuseppe M., Howes Ch. , Speijer J., Stewart Ch., Bemmel H. , Vucic R., Wraight V. Physics 11. Nelson Thompson Learning

Ontario Science Curriculum Grades 11-12http://www.edu.gov.on.ca/eng/curriculum/secondary/2009science11_12.pdf

Resources

Virtual Lab: Measuring the Rate of Radioactive Decay http://glencoe.mcgraw-hill.com/sites/dl/free/0078693896/280405/E18.html

Worksheet on Half- Lifehttp://mysite.cherokee.k12.ga.us/personal/brenda_priest/site/Subject%202%20Notes/1/Virtual%20Half%20Life%20Lab.pdf

Radioactive Decay – picture:http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/earth_origin_lecture.html

Radioactivity -definition and picture:http://hyperphysics.phy-astr.gsu.edu/hbase/nuclear/radact.html

Half-Life – picture on the main site:http://hendrix2.uoregon.edu/~imamura/121/lecture-9/lecture-9.html

Explaining Radioactivityhttp://www.youtube.com/watch?v=o-9yt7OAYmE

Resources

Carbon Dating:http://www.youtube.com/watch?v=31P9pcPStg&feature=related

Carbon 14 Decayhttp://www.youtube.com/watch?v=81dWTeregEA

Using Popcorn to Simulate Radioactive Decayhttp://serc.carleton.edu/quantskills/activities/popcorn.html

Half-Life Graph:http://web.princeton.edu/sites/ehs/osradtraining/radiationproperties/radiationproperties.htm

Resources