When the wind changes direction, there are those who build walls and those who build

windmills…. ancient Chinese Proverb

2010 NYS Coaches Workshop

Physical Science Lab- Wind Power

DESCRIPTION

Teams will build a rotor blade assembly (similar to a propeller) attached to a compact disc (CD).

They will also participate in an activity testing their knowledge about wind and power generation.

The team whose device score combined with the activity score is the highest wins.

EVENT PARAMETERS/CONSTRUCTION

Each team will bring two pre-constructed rotor blade assemblies attached to a standard CD. These must be placed in a box and all parts should be labeled with team name and number …including the box.

Eye protection must be worn during the event.

Resource materials may be used. Materials such as pencils, pens, protractors, rulers, nonprogrammable calculators, and any other similar tools may also be used during the activity.

A multispeed box fan will be used to supply the wind. Support stand, clamps and motor/generator will be supplied by supervisor.

The CD must fit on the mount found in a standard CD player. Modification of the CD IS allowed. No part of the blade assembly may have a radial diameter greater than 14 cm.

In addition the blade made not extend more than 3 cm beyond the mounting plane of the CD. Beyond a radial distance of 3 cm it must also not extend more than 2 cm beyond the mounting plane.

The blade may be made of any nonmetallic substance.

THE BLADE ASSEMBLY

No commercially available blades either modified or unmodified are permitted.

Labeled blade assemblies must be placed in a box also labeled with the team number for impound.

THE COMPETITION

Two mounting areas (High and Low speed) may be prepared by the event supervisor.

The areas will consist of a fan and generator (from a portable CD player. Consult www.soinc.org for setup) with a voltmeter/multi-meter. The motor from the CD player can be mounted with a ring clamp.

Load resistors with a resistance of between 5 and 7.5 ohms will be supplied. The resistance will not be announced until after impounding.

For each fan speed, when the students are ready they will tell the event supervisor to start recording the average voltage during a one-minute interval. Students may use either blade assembly in front of either fan. However, once mounted, they cannot be switched.

The fan used must have a fixed position whose bottom is at least 15 cm above the table.

Students may orient their blade assembly in any direction or position in space.

During set-up students may ask for the fans to be turned on or off to aid them in positioning their blades.

Blades may be modified during set-up, but not during the actual test.

CD mounts must be removed from the CD player before being used as the motor/generator.

Teams may give their blade a single tap to start it moving during the test.

Teams have 8 minutes for both runs. If two stations are set up each station will be 4 minutes.

Teams will indicate when the one minute data gathering should begin during the testing period.

If a computer is not used to gather data during the run then the maximum voltage for that run will be recorded.

Part II Written Questions

These will be taken from a number of subject areas emphasizing alternative energy sources, but particularly wind energy.

Suggested Areas of Renewable Energy

• General information about renewable energy including: – Solar– Wind– Hydroelectric– Tidal– Oceanic tidal energy currents (OTEC)– Geothermal

Suggested Areas of Conservation Practices

General information about energy conservation practices

Recycling

Reusing

Reducing consumption by using materials with greater efficiency.

Suggested Areas of Math formulae

Mathematical relationships and equations used in determining

Heat lostHeat gainedSpecific heat Heat transfer. PowerEfficiencyIntensity (power per area)

SCORING

The final score will be determined adding both the device scores and the activity score. The final score will be determined by the following equation:

50 X Part I Raw Score

Highest Part I Score

The total number of points for Part II is 50.

+ + Part II Score = Final Score( )

If the device fails during a run or stops turning during a period of 15 seconds, the score at that speed will be zero.

Ties will be broken by the best high-speed performance.

Tiers

Tier 1 - all teams whose devices meet all specifications.

Tier 2 - all teams whose devices do not meet specifications listed in section 3.

Tier 3 - All teams who missed impound.

Wind WisdomThere are probably two main reasons for the increasing

interest in wind power. First, most electricity generated today uses non-renewable fuels such as coal, oil and gas. These contribute vast quantities of carbon dioxide to the atmosphere, which many scientists think cause an enhanced greenhouse effect, leading to a warming of the Earth's atmosphere.

The second reason is that advances in wind power science and technology are reducing the cost of wind power to a point at which it is becoming competitive with many other energy sources (at about 8 cents per kilowatt hour). The world has long been searching for a non-polluting, renewable source of energy that is as cheap as coal and oil.

A doubling of wind speed results in as much as an eight-fold increase in power.

The length of the rotor blades is also important – doubling the diameter of the circle made by the blades produces a four-fold increase in power

Since the wind is slowed by friction with the land surface. Modern wind turbines are mounted on towers 40-60 metres high to expose the blades to a higher wind speed.

Infrasound decibel levels are about 15 to 45 db. Scientists continue to work to “cancel out” unwanted sound.

Sample Test Items and NotesThe following are a hodgepodge of questions and notes

used over the years.

2. A piece of metal has several tacks attached to it with wax. After being held over the candle the tacks begin to fall. First the closest one falls, then the next closest, and so on until all eventually fall.

2. A piece of metal has several tacks attached to it with wax. After being held over the candle the tacks begin to fall. First the closest one falls, then the next closest, and so on until all eventually fall.

Is this an example of conduction, convection, or

radiation?

A modern windmill under construction

STATION 1

TURBINE DESIGN

In designing your blade assembly you had to take many factors into consideration. Answer each of the following using the knowledge you had to employ in constructing your rotors.1. Name 6 factors that you should have taken into account when constructing your blade assembly.2. Which of these factors will be the same for engineers constructing the massive turbines that are used in wind farms? 3. How will any of these factors be different? Why?4. The blades on the tall wind turbines look very different from the blades on older traditional windmills. Why? Name at least two reasons and explain.

Use the diagram of the United States showing wind speeds and your knowledge of wind speed to answer the following questions.

6. In what general locations would you find the best wind speeds for powering wind turbines? 7. From what direction do the winds generally blow across the United States? 8. What name is given to the wind belt in which we are located? 9. In a recent article written about wind power the United States was referred to as the Saudi Arabia of wind. What were they trying to say with this phrase? 10. What causes the movement of air that we call wind?

Wind Speeds in US

• How much we affect climate with our use of fossil fuels is called your carbon foot print. Carbon offsetting is then examining our footprint and devising alternative sources of energy that offset our original footprint.

1. What word is defined as the ability to do work?2. How much carbon is released into the air by flying an airplane

5000 miles?• A. 1 pound B. 100 pounds C. 1000 pounds D. 1 ton.3. How much carbon is released by driving 2500 miles in a car?• A. 1 pound B. 100 pounds C. 1000 pounds D. 1 ton4. How much carbon is released by cutting down and burning a 40

foot tree approximately 1 foot in diameter?• A. 1 pound B. 100 pounds C. 1000 pounds D. 1 ton

Carbon Offsetting

5. What are the five largest portions of this graph6. How could you reduce your footprint in the area of food and drink?7. List four things that you can do to offset your carbon footprint.

Conduction, Convection, and Radiation

Heat, Temperature and Energy

• Equations used for this station include but are not limited to:

• Q = mcΔT specific heat water is 1cal/g ｰ C• Q = mHf specific heat of ice is 0.5cal/g ｰ C• Heat of fusion of ice is 80 cal/g ｰ C• Part I• Brendan performed an experiment in which two Styrofoam containers were connected with a

metal bar. The bar had been inserted into the containers through a hole in the Styrofoam cork that fit the top of the Styrofoam cup. (See diagram on accompanying data sheet) In one cup he placed 100 ml of cold water at a temperature of 3 ｰ C. In the second cup he placed 100 ml of hot water at 93 ｰ C.

• His data is shown on the accompanying chart. Using the data and graph to help you, answer the following questions. Place all answers on your answer sheet.

1. To reduce the amount of foreign oil being used in this country ethanol fuel is being used as a fuel additive or, in some cases, as the fuel itself. Name two sources of ethanol.

2. Due to high production costs the US Government subsidizes a large percentage of the cost of ethanol to entice farmers to grow more crops

for use as ethanol. However, use of these crops as fuel is affecting our everyday lives in a negative way. What negative impact is this causing for the average American?

5. The largest geothermal development in the world is found in the United States and is called A. The Hot Springs C. Griffin Development B. The Geysers D. Tectonic Energy 6. Which form of energy is not derived directly or indirectly from the Sun? A. Solar B. Tidal C. Geothermal D. Wind 7. Which form of alternative energy actually still contributes to global warming by disturbing the natural carbon equilibrium? A. Tidal B. Geothermal C. Biomass D. Solar 8. Which of the following is not considered biomass? A. Trees B. Petroleum C. Trash D. Sugarcane 9. What is the total solar energy absorbed by EarthÕs atmosphere, ocean and land masses in one year. A. 55,000 EJ B. 229,760 EJ C. 3,850,000 EJ D. Inestimable. 10. Which material has a higher specific heat allowing it to be a thermal storage substance? A. Water B. Styrofoam C. Copper D. Tile

The following equations may be used in determining your answer:

q = m(∆T)Cp or m = q/(∆T)Cp

Cp for water is 1 cal/gCThe amount of water is written on the cup. The initial temperature of the water is given in C. The water in each cup is heated as described.

For each question choose one of the four answers A through D:

A. Cup A had more heat energy transferredB. Cup B had more heat energy transferredC. Both cups had the same amount of heat energy transferredD. Not enough information is given to determine the answer

Room Temperature 25C

1. Cup A contains 100 grams of water and cup B contains twice as much water. The water in both cups was initially at room temperature. Cup A was heated to 75C and cup B was heated to 50 C. Which cup had more heat energy transferred to it?

100g75°C

200g50°C

A

BA

Resources

http://www.auswea.com.au/WIDP/factsheets.htm

(Australian energy association)http://www.abc.net.au/rn/talks/bbing/stories/s1083409.htmhttp://windpower.fleettrikes.com/lessons.htm

(Windpower Lessons Learned)http://www.kidwind.org/lessons/BBwindpowerbasics.html

(lesson plans - friendly)

Heat and Temperature

Temperature scales (K, ºC, ºF)

Units of measurement (calorie,joules, etc.)

Heat transfer

-conduction

-convection

-radiation

Definitions (work, energy)

OTEC has been around for many years (80?), but the engineering involved seemed daunting.

The amount of ocean available makes this appear much more viable.

What is needed is to create a heat engine to use the difference between the deep cold waters of the ocean and the warmer upper levels. A heat engine is a thermodynamic device placed between a high temperature reservoir and a low temperature reservoir. As heat flows from one to the other, the engine converts some of the heat energy to work energy.

Ocean Thermal Energy Conversion

Other types of Renewable Energy

Solar energy

Pros Cons

-Saves money (for home owner) Initial cost high

-Environmentally friendly Requires large area for panels

-Supports local economy At mercy of weather/climate

-Low maintenance Solar cars are slow

More Renewable Forms

Hydroelectric EnergyPros

-Inexhaustible fuel source

-Minimal environmental impact

-Viable source-relatively useful levels of energy production

-Can be used throughout the world

Cons

-May affect fish (can minimize with fish ladders)

-Depends on presence of fast moving streams

TidalPros

-Does not generate emissions or wastes-Uses an abundant, inexpensive fuel source - Reliability (tides are predictable)-May protect coastline against damage from high storm tides and provide a ready-made road bridge

Cons-Expensive construction needed-Power generated at low demand times-Few good area sites-Barrages may block outlets and affect fish migration

More Renewable Forms

GeothermalPros

-Theoretically inexhaustible energy source-No pollution-Often an excellent supplement to other renewable sources-Does not require structures such as solar panels or windmills to collect the energy--can be directly used to heat or produce electricity (thus very cheap)

Cons-Not available in many locations-Not much power per vent

More Renewable Forms

Recycling

Reusing

Reducing

Energy Conservation

Mathematical Relationships

To determine amount of heat lost or gained

Q = m c ∆T

To determine the amount of heat needed to change the phase of a substance

Q = mHf or Q = mHv