1. Half - Life

2. Rubric for Pros/Cons of Nuclear Power Presentation
Nuclear Unit Syllabus
The final rubric for presentations contains the expectations for the end product – what areas will be included and a scoring range for each area
Rubric for Pros/Cons of Nuclear Power Presentation
Needs Improvement
Minimal Expectation
Exceeds Expectations
Points 1 2 3
Time
Less than 5 min
5 min
› 5 min but ‹ 10 min
Research
No outside research
1 additional source
2 additional sources
Material
No equations
Equations from lecture
Equations from lecture and outside sources
Pros/Cons
Polarized opinions only
Pros/Cons but not balanced
Balanced with final viewpoint and one additional question.

3. Rubric for Team Debates
Nuclear Unit Syllabus
The final rubric for debates contains the expectations for the end product – what areas will be included and a scoring range for each area
Rubric for Team Debates
Needs Improvement
Minimal Expectation
Exceeds Expectations
Points 1 2 3
Valid /convincing mutual arguments
Skeptical response from listeners
Makes valid points
Makes valid and convincing points, convinced others
Research
No research
1 source worked into comments
2 or more sources worked into comments
Presenting /Listening
Distracting
Good presentation, poor listening
Presented well and listened to other team
Debate/ Counter
Polarized opinions /arguments only
Good arguments but not able to counter other team
Good balanced arguments with well thought out counter to other team

4. Presentation and Debate Teams
Tyler/Patrick – Con side in debate
Aaron/Jason – Pro side in debate
Danielle/Tim – Pro side in debate
Jessica/Josh – Con side in debate
Nick/Raquel – Con side in debate
Kristin/Cortney – Pro side in debate
Sean B./Zack – Pro side in debate
Cameron/Sean P. – Con side in debate

5. GLE
Describe radioactivity
Work with real life examples of half-life to discuss problem with nuclear waste storage
Define half-life and come up with half-life equation
Objective
Student will use half-life activity to come up with an equation for half-life, use half-life information to determine the amount of a radioisotope remaining at a given time, and discuss the consequences of storing nuclear waste from a half-life point of view.

6. Radioactivity
In nuclear reactions, the nuclei of unstable isotopes, called radioisotopes, gain stability by undergoing changes accompanied by the emission of large amounts of energy.
The process by which materials give off such energy, in the form of waves (rays), is called radioactivity.
Waves and particles emitted are called radiation.

7. Half-Life Activity
Each table pick up a bag of popcorn, worksheet packet, and 3X5 card.
Follow the instructions on the first page of the worksheet package.
Be prepared to discuss your findings with the rest of the class.
As part of those findings each team will come up with their definition for half-life

8. Half-Life
Every radioisotope has a characteristic rate of decay measured by its half-life
A half-life is the time required for one-half of the nuclei of a radioisotope sample to decay to products.
After one half-life, half of the original radioactive atoms have decayed into atoms of a new element.
How many are left after two half-lives?
What value is never reached?

9. Half-Life Equation
As a class, come up with a working half-life equation.
Activity final = Activity initial (1/2) time passed/half-life

10. Half-Life
Half-lives may be as short as a fraction of a second or as long as billions of years.
Many artificially produced radioisotopes have very short half-lives, a feature that is a great advantage in nuclear medicine.
The rapidly decaying isotopes do not pose long-term biological radiation hazards to patients.

11. Radioactive Intermediates
When radioisotopes decay, they may decay to another element that is also unstable
These elements that are unstable have half-lives of their own.
Elements that are unstable and undergo further decay until a stable nucleus configuration is reached are called radioactive intermediates.

12. Homework
Page 851, # 6 and # 10.