Unit: Matter, Energy, and Ecosystems

Harvard-Westlake School

Show all pertinent measurements, conversion factors and calculations if you would like to earn full credit for this assignment

1. The heat in one cubic foot of gas is 1,021 BTUs. How much heat was purchased?

2. A British Thermal Unit (BTU) is the amount of energy required to heat one pound of water 1°F. Also, it is equivalent to 252 calories. One calorie is the amount of energy required to heat 1 gram of water 1°C. The Harvard-Westlake pool holds 325,000 gallons of water. One gallon of water weighs 8 pounds. Determine the number of pounds of water in the Harvard-Westlake pool.

3. If the conversion of natural gas to heat in the pool were 100% efficient, what change in temperature would be produced?

4. The pool is kept at 80°F and the average temperature during January is 58°F. How much energy is needed to raise the temperature of the pool?

5. How much heat is lost in the conversion from chemical energy to heat in the pool?

6. What is the efficiency of heating the pool?

7. The gas furnace is 80% efficient at converting gas energy to thermal energy in the water. How much energy is initially absorbed by the water?__________

8. Heat is lost from the water to the air, despite the fact that the pool cover is employed most of the day. What is the efficiency of the pool cover? Hint: if the cover was 100% efficient, all of the energy initially absorbed by the water would be retained, but it’s not….

R Area(ft²) t(F) time (hour) Heat (BTU)

Using the same formula, you can determine the amount of heat that has passed through a barrier by

R

BTUs in various fuels

1 gallon of fuel oil: 145,000

1 gallon of gasoline: 125,000

1 cubic foot of natural gas; 1031

1 ton of coal: 25,000,000

1 cord of wood: 20,000,000

1kWh = 3413 BTU

2. This apparatus is used again, but this time a 4.0 ft² piece of 1” thick Styrofoam is used. Since it was lunch hour, the trial ran for two hours, during which .72 BTUs of energy moved across the Styrofoam. What is the R-value for 1” thick Styrofoam? Show your work!

3. Except for the small countries of Luxembourg, Bahrain, Qatar, and Oman, North America uses more energy per person than all other parts of the world. This is true because historically we have always had abundant energy in the form of wood, coal, and oil. Because we have had a large supply, there has been less interest in developing ways to use energy more efficiently. There are several categories of personal energy consumption that we all have some control over: heating and air conditions, heating water, lighting, transportation, and the purchase and use of efficient electrical appliances.

b. How many BTUs would be saved if the thermostat was set for 60 degrees?

c. In the summer season the average valley day-time temperature is 80 degrees. If the air conditioner were set for 65 degrees, how many BTUs would be drawn into the house (and need to be “removed”) in one 12 hour day?

d. ...in the 100 days that average this temperature?

e. Compare to a similar house with double pane glass (R-value of 1.85). How many BTUs would be saved (in the 100 days)by installing this glass in the house?

f. How many kWh of electricity (assuming 100% efficiency)

Energy Review Problems Worksheet

show all calculations with units

area (ft²)time (hr)∆T(°F)

1 kWh = 3413 BTU 1 ton of coal contains 2.5 x 10⁷ BTUs

1 MW (megawatt) = 1000 kW (kilowatts)
1. How many kWhs of energy could be generated by a coal burning power plant that burned 250 tons of coal and was 40% efficient?

2. How much natural gas must be burned in order to produce 52 MWhs of electricity if the power plant was 65% efficient?

3. How many pounds of water could raise in temperature 20°F by the 90% efficient burning of 30.0 cubic feet of natural gas?

4. a. The R-value of a hot water heater insulation blanket is 6.7 and covers an area of 25 square feet. How many BTUs will it save for every hour that it prevents 1°F of temperature change?__________

b. How many cubic feet of gas will that save in one year?

5. What is the efficiency of a gas-burning furnace that heats 5,000 lbs of water 25°F by burning 210 cubic feet of natural gas?

a. How many kWhs of energy would you save in one day?

8. a. How much power is produced by a solar cell that produces 0.06 amps of current and has a voltage of 0.75 volts?

b. if the solar cell had an area of 20 cm² and collected sunlight when the solar constant (the amount of energy available per cubic centimeter) was 0.08 watts/cm², what was the efficiency of the solar cell?
c. How many solar cells would it take to run a 60-watt bulb?
9. If the efficiency of a coal-burning power plant is 65% and the efficiency of energy transmission is 95%, and the efficiency of an electric stove is 85%, how many BTUs of heat could be produced by an electric stove after 0.50 tons of coal have been burned?

10. How many cubic feet of gas must be burned in a 80% efficient pool heater in order to increase the temperature of a 200,000 gallon pool from 60°F to 75°F?

Chapter 15 Text

Section 15-1 through 15-7

Chapter 16 Text

Section 16-1 through 16-7
ONLINE READING QUIZ DUE DATE:__________

Labs:

Examining Evidence for Climate Change Lab

Ozone Lab (optional)

CO₂ Lab

Carbon Dioxide Diet Exercise

Kyoto Protocol Questions

Clean Air Act Worksheet

Global Warming and Sea Level Worksheet

Simple Math for Geniuses

• 
  Greenhouse Effect (how does it work)
  
• 
  Greenhouse Gases (what are they, how are they produced)
  
• 
  Types of Evidence
  
• 
  Forcings and Feedbacks (solar output, albedo, volcanic ash, melting tundra, etc.)
  
• 
  Possible Consequences
  
• 
  Sources and Sinks for CO₂
  
• 
  Carbon Sequestration and Carbon Credits
  
• 
  Relative Temperature Increases throughout History
  
• 
  Thermohaline Circulation
  
• 
  Possible Responses by Humans
  

• 
  Sources (Natural and Anthropogenic)
  
• 
  Types of Pollutants (Primary and Secondary)
  
• 
  NOx Reactions
  
• 
  Factors Which Increase Air Pollution
  
• 
  Thermal Inversions
  
• 
  Photochemical vs. Gray (Industrial) Smog
  
• 
  LA and Smog
  
• 
  Acid Deposition (dry vs. wet)
  

• 
  Types and Locations of Ozone (what is its purpose)
  
• 
  Natural Formation and Destruction of ozone
  
• 
  Anthropogenic destruction of ozone
  
  • 
    CFC’s, halons, furans, and SF₆, CCl₄
    
• 
  Effects of Thinning Ozone
  
• 
  Details of Ozone “Hole” (characteristics, location, changes)
  
• 
  Government Regulations of CFC’s (Montreal, London, Copenhagen)
  

• 
  Keratoses
  
• 
  Carcinomas
  
• 
  Melanomas
  
• 
  ABCD’s of Melanoma
  

• 
  Comparison with Outdoor Air Pollution
  
• 
  Top Three Indoor Air Pollutants
  
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  Where Indoor Air Pollutants can Lurk
  
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  What to do about Indoor Air Pollution
  

• 
  Control vs. Prevention Solutions
  
• 
  Industrial Control Options
  
• 
  Catalytic Converters (and other options to reduce automobile emissions)
  
• 
  Control of Acid Deposition
  
• 
  Government Regulations of Pollution (Energy Policy Conservation Act, Clean Air Act, Kyoto Protocol)
  

• 
  Lessons from CO₂ Diet and Global Warming Problems
  

1. 
   Select the ‘Statewide’ Button. Realize that the data can also be analyzed on different scales (national, regional, etc.)
   
2. 
   Choose any state by clicking on it or the list at the bottom of the window.
   
3. 
   First select the ‘Mean Temperature’. Eventually we will also look at precipitation data for the same state and time period.
   
4. 
   Also be sure to select ‘Annual’ in the Period Menu.
   
5. 
   Leave all of the other settings as they are and click the ‘Submit’ button. It can take a while for the graph and information to load when many people are accessing the site simultaneously so be patient.
   
6. 
   When the information appears, record below the ‘Annual Trend’ for the time period shown. Remember, we want the Trend not the average temperature.
   
7. 
   Go back to the last page and select ‘Precipitation’. Then click on the ‘Submit’ button to display the precipitation information.
   
8. 
   When the information appears, record below the ‘Annual Trend’ for the period shown. Remember, we want the Trend not the average precipitation.
   
9. 
   Now repeat the above process for three more states. Choose states from a variety of areas/regions.
   

According to your results, what is happening to the climate (temp. and precip.) in the United States?

What do the data suggest about the climate trends for the entire country? Don’t forget to look at both temperature and precipitation data.

Does this analysis agree or disagree with the data you collected on a state level. Why or why not?

In the end, do the data prove, disprove, or support the assertion that global warming is occurring? EXPLAIN why or why not in specific detail?
Measuring and Interpreting

Tropospheric Ozone
Background:

There are two types of ozone (O₃). Stratospheric ozone is found high up in earth’s atmosphere and does the vitally important job of absorbing ultraviolet (UV) radiation before it reaches earth’s surface. It’s the ‘good’ ozone. Without stratospheric ozone, biological molecules would be “cooked” by the penetrating UV radiation and living organisms would suffer as a result. This lab focuses on the other kind of ozone- tropospheric ozone.

Tropospheric ozone is a potential human health threat because of its highly reactive nature and ability to form other tertiary pollutants. This ground-level ozone or 'bad' ozone is formed when nitrogen oxides (NO_x) and volatile organic compounds (VOC), collectively called 'ozone precursors', react with sunlight. Emissions from car exhausts, power plants and industrial facilities are the major sources of NO_x and VOC. Another key component in ozone formation is the presence of sunlight. Given the right conditions, this tropospheric ozone can ultimately react to form photochemical smog- the brown air we’ve come to know in Los Angeles.
Procedure:

In this lab we will monitor tropospheric ozone concentrations over the period of several days to determine if any patterns develop. We will be using “badges” that change color when exposed to ozone and a device (called a Zikua ozone meter) that interprets that color change. Badges will be exposed to ambient air for periods of one hour after which they will be evaluated using the Zikua ozone meter. When one badge has been measured, another badge will be exposed to the ambient air for the next hour. This will continue throughout an 8 hour day for three days. We will also leave one badge exposed for all 8 hours of the day to determine the total daily exposure of ozone. All ozone levels will be recorded on an excel spreadsheet for later anaylsis.

Once we have collected the ozone measurements for three days, you should be able to complete the following.

1. 
   Construct a graph that charts ozone levels for each 8 hour day. Put all three or four days on the same graph and label it accordingly (axes and legend). Each data point should be an average of the two readings taken at each time.
   

1. 
   Are there any patterns to ozone formation over the period of a day? If so, what are they?
   

2. 
   Is there any discrepancy between the data for the 3 different days? How well do the data from each day agree with the other days?
   

2. 
   Calculate the average hourly ozone concentration for the 3 days. That means, find the average 0800 reading, the 0900 reading, etc.. Plot these averages on a graph so you can see how the average ozone levels changed over time. Include a ‘best fit’ curve.
   
   1. 
      Does this graph change your interpretation of ozone fluctuations over an 8 hour day? If so, why? If not, why not?
      

2. 
   Which graph is better at illustrating the fluctuations in ozone levels? Explain why you believe the graph to be ‘better’.
   

3. 
   How do the 8 hour total measurements help us understand ozone formation patterns?
   

4. 
   Compare our results to your original hypothesis. Does the data support your hypothesis? Explain.
   

5. 
   How do our result compare with the Air Quality Index Chart that your teacher gave you?