Bellwork 9-24-2014

1. What are 4 components required for a nuclear reactor to power a town (produce electricity)?

**Tests will be returned Thu/Fri

Agenda

Bellwork

Build your own nuclear reactor

Exit slip

Homework

Nuclear ReactorsYou have the following materials at your disposal:

Beaker of waterStrawHot plateAluminum foilWindmill Cork if you need

to stopper your windmill

Build it!

Use your knowledge from the nuclear reactor video to build a nuclear reactor that will power your windmill!

When you are done, answer the following questions about your reactor:1. How did you make your nuclear

reactor work? Give a description of how you built your device.

2. What specific components were needed to maximize efficiency?

Clean UpI will take the beaker off the hot plate with a hot hand

Take out straws and leave on desk

IF you used the tin foil, unwrap it for the next class

Set everything back in the center when your are done

CAUTION – HOT PLATES ARE STILL HOT!

Exit Slip

Stamped questions from nuclear reactor building lab

Homework

Reading on radiationHighlight important informationAnnotate:

Each section – write a mini one sentence summary on the article itself next to the appropriate section 10 sentences total

Example

First paragraph:Radioactivity is the emission of particles or from unstable atoms and can be natural or induced.

Bellwork 9-25-2014

Form your article:

1. What is radioactivity?

2. Describe alpha particle radiation.

3. What two main isotopes are released into the atmosphere from burning coal?

**Pass back tests

Announcements

Points – class monitor

Extra credit drawing

Tutoring Friday is ON!

Why is 36Cl Unstable?

Unstable

Nuclear Strong ForceMysterious force holding nucleus (protons and neutrons) together

Student DemoEveryone up!

4 students start in the center of the desks – this is our NUCLEUS

Question:

• What happened when too many students were added to the “nucleus”

What makes an atom unstable?

Nuclear strong force fails

Too many neutrons or too many protons

Stability is based on a specific ratio of protons to neutrons in the nucleus

In nature, 92 p+ MAX Uranium

Why do we call these atoms unstable?

Atoms like 36Cl are radioactive elements

They break down or DECAY at a specific rate and give off RADIATION

Nuclear RadiationNuclear radiation is the process during which the nucleus of an unstable atom spontaneously breaks down in an attempt to form a morestable nucleus.

This process emits RADIATION

What is radiation?

Waves traveling through space at specific wavelengths

Examples: • Natural radiation from the sun• High energy radiation from space, air or the earth • Background radiation – main source (alpha, beta, gamma)

Share with your neighbor

Write down your answer 1.What is the nuclear strong force?

2.What types of atoms overcome this force?

3.What happens when atoms overcome this force?

Nuclear DecayThe rate at which an element breaks down into a daughter element

This is calculated using half lives

t1/2

Half life: how does it work?

1. What happened after the first half life?2. What happened after the second?

Graphical form

Half LifeThe amount of time it takes for an element to decay to HALF of its original amount

For example: Chlorine-36 will decay to half of its original amount in 301,000 years

How is it measured?

Half life can be determined using any amount of the substance that can be measured:

Mass – gramsProtonsNeutrons

Practice with a neighbor

1.50 grams of Chlorine-36 has a half life of 301,000 years, how much will be left after 1 half life?

2.How much will be left after

2 half lives?

**You will need a calculator!

Half Life Problem 1200 grams of Bismoth-214 has a half life of 20 minutes. Fill in the table to determine how much is left after 4 half lives.

Time passed (min)

Half life Amount remaining (g)

0 0

1

2

3

4

Half Life Problem 2

After 135 days, you have 8 protons of Iron-59 left. This element has a half life of 45 days. How much did you start with?

Time passed (min)

Half life Amount remaining (P+)

0 0

On your own…

Work on the half life problems on your worksheet independently

This is partner work = voice level 2, if you are too chatty you will be moved or asked to leave.

You have 20 minutes to complete this for a stamp

Exit Slip 9-25-2014

Describe WHY elements have half lives and WHAT half life is in your own words using key vocabulary from today:

The WHY: The WHAT:Nuclear strong force - Radioactive elementsRadioactivity - Half Radiation - DecayUnstable - P+, n0, massIsotopes

Work Collection

Bellwork separate

1. Nuclear reactor video questions

2. Exit slip – questions from nuclear reactor lab

3. Radioactivity article

4. Lab sheet from today

5. Exit slip from today

Bellwork 9-30-20141. What types of atoms decay according to their

half lives? What do they give off during this process?

2. If 130 grams of radioactive Carbon-14 has a half life of 5,730 years, how much will be left after 3 half lives? How much time has passed?

Time passed (min)

Half life Amount remaining (g)

0 0123

Homework Answers

1 = 25g left

2 = 25 p+ left

3 = 75 n left

4 = started with 64 g

AnnouncementsVolunteers?

• Class ambassador

• Class monitor

• Class tutors

Test corrections due next Mon/Tue, Oct 6/7Tests have been posted online

If you missed the test you will be required to do test corrections for the whole test in order to raise your 0 to a 3.

Test Correction Reminder

FOR EACH QUESTION YOU GOT WRONG:

1. EXPLAIN: why you got the question wrong

2. WRITE: the correct answer or solution

3. EXPLAIN: why that answer is correct

Half Life ActivityPeriod 2, 4, 5(graph)

In groups of 4 – you will need a paper plate and a lab sheet

1. Follow the procedures on your lab sheet

2. Graph your data using appropriate graph labels:a. Titleb. X and Y axis labelsc. Appropriate scale

3. You have 20 minutes to complete for a stamp

Honors: Another way…

Half life can also be calculated using an equation:

A = A0(1/2)t/h

A = amount remaining

A0 = initial amount

t = time

h = half life of the isotope

Oder of surgeries… I mean operations…

4 easy steps:

Step 1: Plug in the numbers

Step 2: divide the exponent

**Exponent values must ALWAYS be in the same units

Step 3: raise ½ to the power (quotient of step 1)

Step 4: Multiply

Do it…Example 1:

50 grams of Bismoth-214 has a half life of 20 minutes. Use the equation to determine how much is left after 200 minutes.

A = A0(1/2)t/h

A = 50 (1/2) 200/20

A = 50 (1/2) 10

A = 50 (0.00097)

A = 0.05 g

Honors: Practice Problems

Do the first 2 practice problems from the worksheet on separate sheet of paper (homework).

Objective:

Students will be able to create and write balanced chemical equations for alpha, beta and gamma decay.

http://www.youtube.com/watch?v=Zw0pHT47AAU

What is a balanced equation?

In terms of radioactive decay:

• Both sides of the equation arrow have the same TOTAL mass and number of protons.

Interesting Fact

Alpha, beta and gamma decay are responsible for supplying HALF of the Earth’s natural heat

Alpha Decay

Alpha decay is one of the ways unstable elements emit radiationin an attempt to become more stable

Alpha Decay Simulation

On your worksheet is the website you will visit for this simulation

Complete ONE worksheet per pair

You have 20 minutes

Alpha Decay – Exit Slip

5 minutes: In your notes:

Describe alpha decay. On a half sheet of paper

1. What element is emitted and what subatomic particles does it consist of? Helium – 2p+ and 2n0

2. How do you determine the new element produced? Subtract 2 protons (move two to the left on the periodic table)

3. Give an example: Write the alpha decay of Uranium – 235.

Uranium-235 _____________ + _______________

23592 _________ + _________

U

Thorium – 231 Helium - 4

231

90 Th 4

2 He231

90 Th

Bellwork: Honors 8-1-2014

Use the half life decay equation to solve the following problem:

A = A0(1/2)t/h

1. Thorium-228 has a half life of 1.9 years. How much Thorium did you START with if only 3 grams remain after 38 years?

2. Thorium-234 ___________ + _____________

Th ________ + ________

234 90

Bellwork 8-1-20141. Complete the following equation using alpha decay

in HYPHEN notation and SYMBOL notation

Thorium-234 ___________ + _____________

Th ________ + ________

2. Period 6: Use the product from alpha decay in the pervious reaction and put it through beta decay (Hint: not the helium atom!)

__________ ___________ + ____________

234 90

Announcements

Test corrections due next Mon/Tue

I am allowing everyone to correct the first test but in the future I will not giving credit to students who do test corrects with a formative grade <2.7

Grade are posted on the back wall – check as you leave

I will be holding individual conferences with students today while you work

Homework quizzes

Agenda

Bellwork (10 minutes)

Beta Decay (20 minutes total)

Beta Decay debrief (5 minutes)

Gamma Decay notes (10 minutes)

Exit slip – review all three types of decay (5 minutes)

If time – posters on one form of decay to display in the room (extra credit)

Beta Decay

Beta decay is another way that unstable elements emit radiationin an attempt to become more stable

Beta Decay Simulation

On the backside of your worksheet is the website you will visit for this simulation

Complete ONE worksheet per pair

You have 20 minutes

Beta Decay – Debrief5 minutes: In your notes:

Describe beta decay.

1. What particles are emitted during this type of decay?

2. A _________ changes into a ____________.

3. How do you determine the new element produced?

4. Give an example: Write the beta decay of Uranium – 235.

Uranium-235 _____________ + _______________

23592 _________ + _________

U

Gamma Decay

Gamma decay is the lastForm of decay we will talk about whereunstable atoms emitwaves in an attempt to become more stable.

No simulation Gamma Decay:

https://www.youtube.com/watch?v=5U3YVW8Fk-M

In your notes:

Describe gamma decay. What is given off and how do you determine the stable element produced?

1. Give an example: Write the gamma decay of Uranium – 235.

Uranium-235 _____________ + _______________

23592 _________ + _________

With a partner…

Make a poster of your own rendition of alpha, beta or gamma decay that would be easy to understand by someone who has NEVER learned the subject.

Include: What is emitted and what it consists of

How mass and # of protons change

How you determine the new element produced

An example of the decay used in an equation (HINT: this can be used to hit the other points)

Homework 8-1-2014

Finish the packet on alpha, beta and gamma decay by Thursday/Friday

Homework quiz Thu/Fri – bellwork

Exit Slip 8-1-2014Fill in the blanks:

1. Alpha decay radiation emits an ________ particle that is also called _________. This element consists of ____ protons and ____ neutrons. The daughter element produced has _____ less protons and its mass is reduced by ______.

2. Beta decay radiation emits an ________ with a mass of ______ and a atomic (proton) number of ________. A _______ is changed into a __________ in the process. The daughter element produced has ______ more proton and the ________ mass.

3. Gamma decay radiation emits __________ that have a mass of _____ and _____ protons. The daughter element produced is ______.