15.2 Energy Conversion and Conservation Friday, December 4, 2009 Opener #5 1. Complete the following...

15.2 Energy Conversion and Conservation

Friday, December 4, 2009Opener #51. Complete the following questions from sect. 15.2 pg. 459 #1-5, 9-10.

*Pick up computers as you finish your opener.*Have out notes for problem examples with specific heat.*Have out packet from the other day to grade.

CW: Notes - problem examples and Finish computer labCW/HW: Book Assignment due on Monday which is your study guide this time...

*Study for TEST on Tuesday over ch. 14, 15, & 16 (mostly 14.1, 15.1-15.2, & 16.1) - mostly on application of problems using formulas and vocabulary...

CW: CPS problems if time; if not we will use on Monday as part of review.

SKIP THIS PAGE....


Textbook assignment due on Monday. Test Tuesday!ch. 14 study guide & assessment pg. 440 Concept Map “Thinking Visually”, pg. 441 #1-4, 6, 9-12; pg. 442 #28-29, 32-33. (14 problems)

Ch. 15 study guide & assessment pg. 468 “Thinking Visually”pg. 469 # 1-20pg. 470 #23, 25-29, 32-33

ch. 16 assessment pg. 495 #29 AND pg. 478 #9-11

SKIP THIS PAGE...


Opener #6 - Monday, December 7, 2009Have out your power project with your appliance and items at home. Answer the following questions with your items.

Convert all units to watts if you haven’t already. Example 746 Watts = 1 hp.Power = IV (current in amps times voltage) = power in watts...1. Which item used the most power?2. Which item used the least amount of power?3. Which item(s) surprised you when you compared them?4. As a group, who had the item that used the most power? 5. How does power relate to energy?6. Name at least 3 different things you can do to help save energy by cutting back on energy usage.


Opener #7 - Tuesday, December 8, 2009You do not have to use complete sentences today only due to test.1. Answer questions in Sect.16.1 assessment pg. 478 #1-6.

Turn in homework that we graded yesterday with the number missed. If you didn’t have the homework yesterday, you will need to come in and grade during lunch or in the morning before school to get credit. Clearly show the problems you missed.

Turn in computer lab today or tomorrow.

Have out 2 sheets of notebook paper, pick up blue answer sheet, and pick up reference form with formulas and specific heat table...

Turn in egg drop lab essays to me for those who had to make up the lab if you haven’t already turned in.


Electrical power

P = IV

amps * volts = Watts for what we are doing...

Main article: Electric power

[edit]

Instantaneous electrical power

The instantaneous electrical power P delivered to a component is given by

P(t) = I (t) times V(t)

where

P(t) is the instantaneous power, measured in watts (joules over second)

V(t) is the potential difference (or voltage drop) across the component, measured in volts

I(t) is the current through it, measured in amperes

http://en.wikipedia.org/wiki/Electric_power

http://en.wikipedia.org/w/index.php?title=Power_(physics)&action=edit&section=4

http://en.wikipedia.org/wiki/Watt

http://en.wikipedia.org/wiki/Watt

http://en.wikipedia.org/wiki/Joule

http://en.wikipedia.org/wiki/Second

http://en.wikipedia.org/wiki/Potential_difference

http://en.wikipedia.org/wiki/Volt

16.1 Thermal Energy and Matter

Opener #4 Thursday, December 3, 20091. Complete sect. 15.1 pg. 452 #6-9 - Show work for problems including formulas used.

HW: Power Project - 15 items with amount of wattage used...due tomorrow.CW: Notes 16.1CW: Grade packet assignment from yesterday on Friday...

HW: Work on problems assigned out of book - due on Friday by end of period.

CW: Computer Lab (Plan A) Friday - CPS unit activity with problem applications only... (or Plan B)

Test next Tuesday over ch.14-16 (mostly 14.1, 15.1-15.2 & 16.1)

Our final exam has been scheduled for the Monday before break. 1st and 3rd periods..

Larry’s Pizza day will be that Monday if approved by admin. during lunch.

2nd and 4th block classes will be on Tuesday...


Opener #11 - Tuesday - February 23, 2010Show work or write in complete sentences.

1. Complete questions section 15.1 pg. 452 #1-5.

HOMEWORK: Obtain power usage from 10 different applicances, electronics, motors/engines, etc. from home. Remember P = IV if you do not see WATTS on your items, where I is the current in amps and V is voltage in volts. 746 Watts = 1 horsepower... record as both units if listed as horsepower...DUE tomorrow...

Homework: ch.14-15-16 problem handout sheet due on Thursday...

CW: Notes 16.1 start with slide #9CW: Horsepower Lab...CW: Upload movies as Quicktime to your desktop... Then we will see about putting them on the web... with instructions...CW/HW: Finish all other notes in packet by reading sections by FRIDAY...TEST March 3rd on chapters 14-15-16 (14.1, 15.1, 15.2, 16.1 main lessons)....


Opener #13 - Thursday - February 25, 2010Show work or write in complete sentences.DO NOT PICK UP COMPUTERS YET...1. Complete questions section 15.1 pg. 452 #6-9.

CW: LAB - Temperature Probes + Specific Heat Lab... After completing, turn in questions. Return instructions to tray; you may write on data sheet with answers to questions... Turn in when done with lab...Have out HW Problems handout (given out on Monday) to check/turn in...CW/HW: Finish all other notes in packet by reading sections by TOMORROW..TEST WED., March 3rd on chapters 14-15-16 (14.1, 15.1, 15.2, 16.1 main lessons)....

Note that your video should be uploaded no later than Monday to get full credit...Finish Energy and Work Lab on Friday and turn in...Be sure you have turned in recent assignments: Horsepower Lab, Energy & Work Computer Lab, etc. (Check Pinnacle to always keep up with what you still need to do....)Be sure 10 items with power amounts are with opener #12.


Opener #14 - FRIDAY, February 26, 2010Show all work or write in complete sentences.Be sure you did opener #13 from yesterday (3rd block particularly...) pg.452 #6-91. Complete questions in Section 15.2 pg. 459 #1-5, 9-10.

CW: Finish Energy Conservation with Hot/Cold Water & Specific Heat Lab for Food Energy - discussion - turn in box before leaving today...

CW: Study Guide Questions (no answers will be provided for this unit.) TEST will be next Wednesday (March 3rd)... due Monday if not finished in class!CW: Computer Sample Problems online at http://podcast.bryantschools.org/users/dvannCW: Be sure you turn in any previous assignments. Make-up lab today after school for anyone who needs to stay for this new lab, siphon lab, or other make up labs... including computer lab which can be completed here or at home...

Finish & TURN IN Work and Energy Computer Lab in box if not finished on Wednesday.

http://podcast.bryantschools.org/users/dvann


Opener #12 - Wednesday, February 24, 2010Have out your power project with your 10 electronics, appliances and items at home power usage list. Answer the following questions with your items.

Convert all units to watts if you haven’t already. Example 746 Watts = 1 hp.Power = IV (current in amps times voltage) = power in watts...1. Which item used the most power?2. Which item used the least amount of power?3. Which item(s) surprised you when you compared them?4. How does power relate to energy?5. Name at least 3 different things you can do to help save energy by cutting back on energy usage. 6. As a group, who had the item that used the most power?

CW: Work and Energy Computer LabCW: Share imovie as Quicktime then upload to podcast vannstudent blog... (5 groups have been successful so far...)HW: Problems sheet due tomorrow for accuracy!


Count Rumford supervised the drilling of brass cannons in a factory in Bavaria.

From his observations, Rumford concluded that heat is not a form of matter.


In what direction does heat flow spontaneously?Heat is the transfer of thermal energy from one object to another because of a temperature difference.

Work and Heat

Heat flows spontaneously from hot objects to cold objects.


A drill is a machine that does work on the cannon. Remember that no machine is 100% efficient. Some of the work done by the drill is useful, but some energy is lost due to friction.

Heat flows from the cannon to a surrounding water bath because the cannon is at a higher temperature than the water.

Work and Heat

Copyright © by Holt, Rinehart and Winston. All rights reserved.

ResourcesChapter menu

Measuring Temperature

Chapter 16

Click below to watch the Visual Concept ON THE LINK AND THEN CLICK PLAY. THEN COME BACK TO KEY NOTE USING COMMAND AND TAB KEY (OR USING KEYNOTE ICON)

Visual Concept

Section 1 TemperatureDO NOT SKIP VIDEO OR VISUAL CONCEPTS. IT WILL HELP YOU!

http://my.hrw.com/sh/hk6_0030390966/student/ch13/sec01/vc07/hk613_01_v07fs.htm




What is the temperature of an object related to?

Temperature

Temperature is related to the average kinetic energy of the particles in an object due to their random motions through space.


Temperature is a measure of how hot or cold an object is compared to a reference point.

• On the Celsius scale, the reference points are the freezing and boiling points of water.

• On the Kelvin scale, absolute zero is defined as a temperature of 0 kelvins.

Temperature



IF YOU NEED TO REVIEW THE 3 DIFFERENT TEMPERATURE SCALES, YOU CAN WATCH THIS VIDEO. This is one that you may continue if you do not need to review.

Chapter 16

Click below to watch the Visual Concept.

Visual Concept

Section 1 Temperature






Measuring Temperature

Chapter 16


Visual Concept






As an object heats up, its particles move faster, on average. The average kinetic energy of the particles increases.

• One way that heat flows is by the transfer of energy in collisions.

• On average, high-energy particles lose energy. Low-energy particles gain energy.

• Overall, collisions transfer thermal energy from hot to cold objects.

Temperature


What two variables is thermal energy related to?Thermal energy is the total potential and kinetic energy of all the particles in an object.

Thermal Energy

Thermal energy depends on the mass, temperature, and phase (solid, liquid, or gas) of an object.


Thermal energy depends on mass. A cup of tea and a teapot full of tea can have the same temperature.

• The average kinetic energy of the particles is the same in the cup and the pot.

• There is more thermal energy in the teapot because it contains more particles.

Thermal Energy


Thermal energy depends on temperature. Compare a cup of hot tea with a cup of cold tea.

• In both cups, the tea has the same mass and number of particles.

• The average kinetic energy of particles is higher in the hot tea, so it has greater thermal energy.

Thermal Energy


Thermal energy depends on mass and temperature.

A. The tea is at a higher temperature than the lemonade.

B. The lemonade has more thermal energy because it has many more particles.

Thermal Energy



Temperature and Heat

Chapter 16


Visual Concept







Watch the video on Temperature vs. Heat Differences. Be able to contrast as an essay question.

QuickTime™ and a decompressor

are needed to see this picture.


What causes thermal expansion?Thermal expansion is an increase in the volume of a material due to a temperature increase.

Thermal Contraction and Expansion

Thermal expansion occurs when particles of matter move farther apart as temperature increases.


If you take a balloon outside on a cold winter day, it shrinks in a process of thermal contraction.

• As temperature decreases, the particles that make up the air inside the balloon move more slowly, on average.

• Slower particles collide less often and exert less force.

• Gas pressure decreases and the balloon contracts.

Thermal Energy


If you bring the balloon inside, it expands.

Gases expand more than liquids and liquids usually expand more than solids.

Thermal Energy


As temperature increases, the alcohol in a thermometer expands, and its height increases in proportion to the increase in temperature.

In an oven thermometer, strips of steel and brass expand at different rates as the coil heats up. The coil unwinds, moving the needle on the temperature scale.

Thermal Energy


How is a change in temperature related to specific heat?Specific heat is the amount of heat needed to raise the temperature of one gram of a material by one degree Celsius.

Specific Heat

The lower a material’s specific heat, the more its temperature rises when a given amount of energy is absorbed by a given mass.


When a car is heated by the sun, the temperature of the metal door increases more than the temperature of the plastic bumper.

The iron in the door has a lower specific heat than the plastic in the bumper.

Specific Heat


Specific Heat



Specific Heat Formula

Energy TransferChapter 16


Visual Concepthttp://my.hrw.com/sh/hk6_0030390966/student/ch13/sec02/vc04/hk613_02_v04fs.htm




In this formula, heat is in joules, mass is in grams, specific heat is in J/g•°C, and the temperature change is in degrees Celsius.

Specific Heat


Calculating Specific HeatAn iron skillet has a mass of 500.0 grams. The specific heat of iron is 0.449 J/g•°C. How much heat must be absorbed to raise the skillet’s temperature by 95.0°C?

Specific Heat


Read and UnderstandWhat information are you given?

Specific Heat


Plan and SolveWhat unknown are you trying to calculate?

What formula contains the given quantities and the unknown?

Specific Heat


Plan and SolveReplace each variable with its known value.

Specific Heat


Look Back and CheckIs your answer reasonable?

Specific Heat


Look Back and CheckIs your answer reasonable?

Round off the data to give a quick estimate.

Q = 500 g × 0.5 J/g•°C × 100°C = 25 kJ

This is close to 21.4 kJ, so the answer is reasonable.

Specific Heat


1. How much heat is needed to raise the temperature of 100.0 g of water by 85.0°C?

Answer:

Specific Heat


1. How much heat is needed to raise the temperature of 100.0 g of water by 85.0°C?

Answer:

Q = m * c * ∆T = (100.0 g)(4.18 J/g•°C)(85.0°C)

= 35.5 kJ

Specific Heat


2. How much heat is absorbed by a 750-g iron skillet when its temperature rises from 25°C to 125°C?

Answer:

Specific Heat


2. How much heat is absorbed by a 750-g iron skillet when its temperature rises from 25°C to 125°C?

Answer:

Q = m * c * ∆T = (750 g)(0.449 J/g•°C)(125°C – 25°C)

= (750 g)(0.449 J/g•°C)(100°C)

= 34 kJ

Specific Heat


3. In setting up an aquarium, the heater transfers 1200 kJ of heat to 75,000 g of water. What is the increase in the water’s temperature? (Hint: Rearrange the specific heat formula to solve for ∆T.)

Answer:

Specific Heat


3. In setting up an aquarium, the heater transfers 1200 kJ of heat to 75,000 g of water. What is the increase in the water’s temperature? (Hint: Rearrange the specific heat formula to solve for ∆T.)

Answer: ∆T = Q / (m x c)= 1,200,000 J/(75,000 g × 4.18 J/g•°C)

= 3.8°C

Specific Heat


4. To release a diamond from its setting, a jeweler heats a 10.0-g silver ring by adding 23.5 J of heat. How much does the temperature of the silver increase?

Answer:

Specific Heat


4. To release a diamond from its setting, a jeweler heats a 10.0-g silver ring by adding 23.5 J of heat. How much does the temperature of the silver increase?

Answer: ∆T = Q / (m x c)= 23.5 J/(10.0 g × 0.235 J/g•°C)

= 10.0°C

Specific Heat


5. What mass of water will change its temperature by 3.0°C when 525 J of heat is added to it?

Answer:

Specific Heat


5. What mass of water will change its temperature by 3.0°C when 525 J of heat is added to it?

Answer: m = Q / (∆T x c)= 525 J/(3.0°C × 4.18 J/g•°C)

= 42 g

Specific Heat


On what principle does a calorimeter operate?A calorimeter is an instrument used to measure changes in thermal energy.

Specific Heat

The lower a material’s specific heat, the more its temperature rises when a given amount of energy is absorbed by a given mass.


According to the law of conservation of energy, the thermal energy released by a test sample is equal to the thermal energy absorbed by its surroundings.

The calorimeter is sealed to prevent thermal energy from escaping.

Specific Heat


A calorimeter is used to measure specific heat. A sample is heated and placed in the calorimeter. The temperature change is observed.

Specific Heat


Assessment Questions - answer these to see what you remember1. What is the thermal energy of an object?

a. the total number of atoms or molecules

b. the total kinetic energy of the atoms or molecules

c. the average kinetic energy of the atoms or molecules

d. the average mechanical energy of the atoms or molecules


Assessment Questions

1. What is the thermal energy of an object? a. the total number of atoms or molecules

b. the total kinetic energy of the atoms or molecules

c. the average kinetic energy of the atoms or molecules

d. the average mechanical energy of the atoms or molecules

ANS: B



2. What causes a gas to expand when its temperature is increased?a. The number of particles increases as temperature

increases.b. Each particle expands as its temperature increases, so

the total volume increases.c. As temperature increases, more electrons leave atoms

and move separately.d. As gas particles move faster, they overcome some

forces of attraction.



2. What causes a gas to expand when its temperature is increased?a. The number of particles increases as temperature

increases.b. Each particle expands as its temperature increases, so

the total volume increases.c. As temperature increases, more electrons leave atoms

and move separately.d. As gas particles move faster, they overcome some

forces of attraction.

ANS: D



3. The specific heat of water is 4.18 J/g•°C. How much heat is required to raise the temperature of 1,000 grams of water by 50°C? a. 83.6 J

b. 83.6 kJ

c. 209 J

d. 209 kJ



3. The specific heat of water is 4.18 J/g•°C. How much heat is required to raise the temperature of 1,000 grams of water by 50°C? a. 83.6 J

b. 83.6 kJ

c. 209 J

d. 209 kJ

ANS: D



4. What property of matter can be measured using a calorimeter? a. temperature

b. thermal expansion

c. specific heat

d. mass



4. What property of matter can be measured using a calorimeter? a. temperature

b. thermal expansion

c. specific heat

d. mass

ANS: C



1. Temperature is the transfer of thermal energy from one object to another.

TrueFalse



1. Temperature is the transfer of thermal energy from one object to another.

TrueFalse

ANS: F, Heat


When you are finished with today’s notes, be working on your homework problems handout which is due on THURSDAY!

Tomorrow, your mini-project with your power usage of electronics, appliances, and/or motors is to be brought to class tomorrow.

LAB: Horsepower lab today...

Share iMovie by converting with QuickTime to your desktop; I need to see you when you are ready to do this. Afterwards, we will attempt to upload to the student blog.

The student blog is going to be at http://podcast.bryantschools.org/users/vannstudent

I will need to show you how to upload to this NEW blog. (Keep our fingers crossed that all will work out.)

15.2 Energy Conversion and Conservation Friday, December 4, 2009 Opener #5 1. Complete the following...

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