1. 11/3 - 8th Grade Agenda Learning Objective: Learn about Half Life
Collect Hw: Reading & Notetaking p.84 & 85
Class Reading p.160 – 163
Hw: Reading & Notetaking: p.86 – 87
Reminder: Chap 4 Test on 11/4
Reminder: Elemental Super Hero Project Due:11/13 (15 Points)

2. Daily Reflection
Prompt: Write 3 facts that you know about Radioactive Elements.

3. What is Nuclear Fusion?
Atomic Nuclei combine to form a larger nucleus, releasing huge amounts of energy in the process

4. What is Nuclear Fusion?
Inside of a star, hydrogen combine to from helium
Also used in Hydrogen Bombs
E = mc2

5. What is a Supernova?
Elements heavier than iron is produced when the most massive star explode in a supernova explosion
Everything in the universe including yourself is made from star dust

6. What is Radioactive Decay?
The process of atomic nuclei of unstable isotopes releasing fast moving particles and energy.
Particles and energy produce during radioactive decay are forms of nuclear radiation

7. Alpha Decay
2 protons and 2 neutrons are lost

8. Beta Decay Neutrons breaks up into a electron and proton.
Electron (Beta Particle) is given off by a nucleus during radioactive decay

9. Gamma Decay
Most energetic form of light (Invisible to us) is given off during radioactive decay

10. What is the length of time needed for half the atoms of a sample of isotope to decay called?
Half Life
Sodium – 24’s half life is 15 hours
Carbon -14’s half life is 5,730 years
Chlorine – 36’s half life is 400,000 years
Uranium-238’s half life is 4.5 billion years.

11. How can scientists use Carbon-14 to date fossils?
By seeing how much carbon-14 is present in the fossil, scientists can determine how old the fossil is (up to 60,000 years).
Carbon-14 has a half life of 5,730 years.
Question: If a fossil has only half the normal amount of Carbon-14, how old will it be?
Answer: 5,730 years old.

12. Atoms with the same number of protons and different numbers of neutrons are called……
Isotopes

13. What is a Mass Number of an Isotope?
Mass Number is the sum of the protons and Neutrons in the nucleus of an atom.

14. Carbon – 12 vs Carbon - 14
Carbon normally has 6 protons and 6 neutrons. Questions: What is it’s mass number?
Answer: 12. Known as Carbon - 12
An Isotope of Carbon (one out of every trillion carbon atoms) has 6 protons and 8 neutrons. Questions: What is it’s mass number?
Answer: 14. Known as Carbon - 14

15. How can Radioactive Tracer be used in Medicine?
Scientists inject radioactive tracers into the body to see the organ and other structures to detect and treat medical problems.