Energy Sources and Alternative Energy Lab wk4sci207

Environmental Science Table of Contents

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Lab 4 Energy Sources and Alternative Energy

Energy Sources and Alternative Energy

Concepts to Explore

• Energy

• Non-renewable sources

• Passive solar energy

• Active solar energy

• Photovoltaics

• Wind energy

Introduction

Energy is essential for life to exist in any environment. As humans, we consume huge quantities of energy every day. This, however, comes with many consequences. Although energy is abundant everywhere, useful energy is much more difficult to produce and less efficient for our daily activities. Over 90% of produced ener- gy comes from non-renewable resources. These include oil, natural gas, coal, and uranium. Not only are our sources of fossil fuels and other nonrenewable energy sources depleting, but many of these sources produce toxins that are harmful to our bodies and the environment. Fossil fuel depletion, deforestation, pollution, and global warming are just a few negative effects that come from the combustion of many nonrenewable energy sources.

Non-renewable Sources

Oil is derived from the remains of plants and animals that lived in aqueous environments millions of years ago. Over very long periods of time, the heat from the Earth’s core and the pressure from the sand, silt, and rock that deposited on top of it turns the remains into crude oil. Scientists and engineers explore areas to find rocks that indicate the presence of oil un- derneath, and drill through them to tap into the reservoir holding the yel- lowish-black substance. After the oil is drilled, it is sent to a refinery to be separated into usable petroleum products—most of which are used to pro- duce energy. These include: heating oil, jet fuel, heavy fuel oil, liquefied petroleum gases, and gasoline.

? Did You Know... The following products are made from petroleum?

• Ink • Deodorant • Crayons • Dishwashing liquid • Eyeglasses • CDs and DVDs • Tires • Ammonia • Artificial heart valves

Coal is another nonrenewable energy source that is derived from sedimentary rock comprised mainly of car- bon and hydrocarbons. It takes millions of years to create and forms from dead plants that became trapped under dirt and water. There are four main types of coal: anthracite, bituminous, subbituminous, and lignite. Coal is classified into these groups based on the amount of carbon it contains. When coal is buried less than 200 feet underground, surface mining technologies can be used to extract it. However, it if is deeper than 200 feet, underground mining is performed to reach and extract the coal. More than 90% of the coal mined in the US is used for generating electricity. Even though coal is an inexpensive fuel source, it is important to re-

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Energy Sources and Alternative Energy

member that mining alters the topography and also can cause secondary pollution to waterways and the air.

Similar to oil and coal, natural gas is produced from decaying plant material and very long periods of time. It is used in industrial and residential arenas for heating and electricity. Although natural gas is a relatively clean-burning fossil fuel, it is not without harmful environmental impacts.

While products from oil, coal, and natural gas help to do many things, finding, moving, and using them can harm the environment through air, water, and other secondary pollution. There are many ways that we can reduce the amount of energy consumed in our daily lives. Proper use of insulation, using energy efficient light bulbs, use of programmable thermostats, carpooling, and even driving the speed limit can all help conserve energy, the environment, and even money! Two major forms of renewable energy are also being utilized - solar and wind energy.

Earth receives most of the sun’s energy through forms of light to minimize the dependence on nonrenewable sources. This solar energy can be converted into heat and other forms of energy such as electricity. The sun’s light is Earth’s most abundant source of energy and is also free of cost. For these reasons, scientists have studied ways to convert and harness the energy of the sun for centuries. There are four major forms of solar energy: passive, active, photovoltaic, and solar thermal electric energy. Each form of solar energy has its unique set of advantages and disadvantages, but used properly can help in the conservation of energy and our planet.

Passive Solar Energy

When the sun is the only moving object and source of light and/or heat in energy transfer the process is called passive. This means that no electricity is produced and only the sun is used to transfer energy to an- other object or group of objects. Passive solar energy is utilized in many households and buildings. Window placement, insulation, and ventilation are key components to properly utilize the sun’s power in order to keep cool in the summer and warm in the winter. Proper construction planning is key for these situations.

Active Solar Energy

Active solar energy, also known as active solar heating, is similar to its passive counterpart in the way that it captures energy from the sun. However, it goes one step further and uses a liquid to store and transfer the energy. Active solar heating systems often use the sun to heat an enclosed fluid such as water. Once heated the fluid can be stored for later and used the next time someone needs to take a hot shower! These systems often use pumps to move the fluid during the heat transfer process, and can become much more complicat- ed. This makes active solar heating less efficient because pumps require additional power to run.

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Energy Sources and Alternative Energy

Photovoltaics

When electrical energy is produced directly from the energy of the sun PV cells, or photovoltaic cells, are used. These cells are very common and often found on top of street lights, used in solar powered calculators, residential homes, and even watches. PV cells consist of tiny strips of semiconductors, such as silicon, which are joined together. When the sun strikes these strips the material becomes excited. If there is enough energy present, electrons are emitted from the excited atoms. This flow of electrons produces an electrical current, which can then be used as energy. Photovoltaics can be very expensive in large applications, but cost has continuously fallen as the technology is enhanced.

Figure 1: Several different designs of wind turbines exist, but the most common looks like an oscillating fan or wind mill. All of the different styles of turbines try to maximize the efficiency of the turbine at different wind speeds.

Focusing solar energy using mirrors can help intensify heat transfer. This ancient technology has recently been utilized in large scale projects to produce electrical energy. In this process reflected sunlight is focused on pipes of oil, which are then heated. Oil is used because it is much more conductive than water and can be heated with greater ease. The heat in the oil is then transferred to water and creates steam. This steam spins a turbine to create an electrical current. Converting the sun’s energy in this manner requires larger areas of

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Energy Sources and Alternative Energy

land but is very useful. Solar thermal electric energy can even be used to increase the efficiency of heat pumps and power plants.

Wind Energy

Solar energy is what drives our planet. Almost every living organism converts the sun’s rays into a useful form of energy. At a quick glance there seem to be very few drawbacks from using solar energy. However there are some big issues with using solar power for energy. First, solar energy can only be used in places where sunlight is abundant and when it is available. Solar energy is not available at night and it would be pointless to put PV cells in an area where the sun rarely shines. Clouds can also create a problem when trying to cap- ture energy from the sun. If you need power but have no light you are just out of luck. Second, storing solar energy is difficult and inefficient. This means that if you do not need the energy at the time it is converted it will be wasted. Finally, the equipment involved in many solar devices is expensive and tough to maintain. With this being said, advancements are being made every day and solar energy continues to expand.

Like solar, wind power has many advantages to it. Unlike fossil fuels, wind power is clean, abundant and free. Wind is even more abundant than energy from the sun since it can potentially be harnessed 24 hours out of the day. Wind energy uses a turbine to convert kinetic energy from the wind into mechanical energy, which in turn produces electricity.

Just like solar energy, wind has its disadvantages. The major disadvantage is that wind is unpredictable. Alt- hough unreliability can be reduced by choosing proven locations, no one can precisely predict wind speeds over large areas of land. This uncertainty requires the use of backup energy sources and storage devices. Wind farms are also by nature, very large and expensive. Their size makes them unappealing near populated areas, which means that they must be a great distance from the area they are actually supplying power to. Large wind farms can also disrupt radio, television, and phone reception. Although there are problems with wind energy production, the global power output due to wind has increased exponentially over the years. This statistic emphasizes the need for future development in alternative energy sources in order to maintain the planet we live on today.

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Energy Sources and Alternative Energy

Experiment 1: The Effects of Coal Mining

Coal mining, particularly surface mining, leads to large areas of land being temporarily disturbed. The mine workings collect and conduct water that is in contact with the widespread pyrite, a mineral that produces iron and sulfuric acid when exposed to air and water. In this lab, you will test the effect of pyrite and coal on fresh water. Follow the procedure below to complete Experiment 1 on the effects of coal mining.

Materials

(2) 100 mL Beakers

1 tsp. Crushed pyrite

1 tsp. Activated carbon

6 pH test strips

Permanent marker

Measuring spoon

*Water

*You must provide

Procedure

1. Read through the Experiment 1 procedure and then record your hypothesis on the effects of pyrite and

coal on water acidity on the Week 4 Lab Reporting Form.

2. Label three beakers: Water, Pyrite, and Carbon.

3. Pour 100 mL of water into each beaker.

4. Test and record the initial pH of each beaker and record the results in Table 1 on the Week 4 Lab Report-

ing Form.

5. Place 1 heaping teaspoon of the crushed pyrite and activated carbon into their corresponding beakers.

6. Set the beakers in a warm place for 48 hours, then test the pH of each. Record the results in Table 1 and

answer the Post-Lab Questions on the Week 4 Lab Reporting Form.

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Energy Sources and Alternative Energy

Experiment 2: Solar Energy

The sun’s energy is free, plentiful, non-polluting, and can be converted into electricity with the use of photo- voltaic cells. Also called a solar cell, these panels capture sunlight and emit a current that can be used to power many things, including the small motor attached to the solar panel in your kit. However, many people argue that this source of energy is unreliable due to varying weather conditions. In this experiment, you test the effectiveness of solar energy under direct sunlight and compare it to solar energy subjected to a number of independent variables. Follow the procedure below to complete Experiment 2 on solar energy

Materials

Solar cell, motor, and rotating disk

Permanent marker

Red, green, blue and yellow filters (cellophane)

Aluminum foil

Protractor

*Incandescent light source (fluorescent and halo-

gen light sources are not suitable for this experi-

ment)

*You must provide

Procedure

1. Read through the Experiment 2 procedure and then record your hypotheses on the effectiveness of solar

energy under direct sunlight and when exposed to other variables on the Week 4 Lab Reporting Form.

2. Record the weather of the day in the bottom of Table 2 on the Week 4 Lab Reporting Form.

3. Draw a dot on the disk using the permanent marker, near the outer circumference of the circle. This will

help you to visualize the rotation of the motor once it starts spinning.

Note: The faster the disc spins, the more energy the solar panel is producing.

4. Test your solar motor by holding it close to an incandescent light source, and record the wattage in Table

2. Observe the efficiency (the speed of the rotating disc) of the solar cell as you vary the distance be-

tween the motor and the light source by moving the motor closer and farther from the bulb You may need

to give the wheel a tiny nudge to get it started. For all observations in this experiment, you do not need to

calculate the exact rotation speed but may use observational values such as very slow, slow, medium,

fast, very fast.

Note: Incandescent light sources refer to light bulbs which encase a filament wire. They are typically

shaped like an upside-down pear and screw into table lamps. Do not use a fluorescent or halogen

light source.

5. Take the motor outside and face the solar panel directly at the sun (even when overcast the sun is still

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Weather and Climate Change

present). Observe the efficiency of the solar cell as you hold it in direct sunlight. Record your observations

in Table 2 on the Week 4 Lab Reporting Form.

6. Face the solar panel exactly 45 degrees away from the sun, using the protractor to measure the angle

from the sun. Observe the efficiency of the solar cell when it is struck by sunlight at this angle. Record

your observations in Table 2 on the Week 4 Lab Reporting Form.

7. Use the aluminum foil to create a reflector that reflects sunlight onto the solar panel. This should not cover

the panel, but enhance the amount of sunlight that hits the panel surface. Observe the efficiency of the

solar panel with the reflector and record your observations in Table 2 on the Week 4 Lab Reporting Form.

8. Use the black construction paper to shade 25%, 50% and 75% of the solar panel. Observe the efficiency

of the solar panel under each condition and record your observations in Table 2 on the Week 4 Lab Re-

porting Form.

9. Fold a piece of the red cellophane over two times so that you have a piece of cellophane that is four-

layers thick (it should be one quarter of the original size).

10. Hold the red cellophane over the exposed portion of the solar panel, and observe the efficiency of the so-

lar panel. Repeat this process with the yellow, green, and blue cellophane. Observe the efficiency of the

solar panel when each color filter is used to cover the solar panel. Record your observations in Table 2

and answer the post lab questions on the Week 4 Lab Reporting Form.

Figure 2: Each cellophane sheet should be folded into quarters to create the desired rotational effect.

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Weather and Climate Change

Appendix Good Lab Techniques

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Good Lab Techniques

Good Laboratory Techniques

Science labs, whether at universities or in your home, are places of adventure and discovery. One of the first things scientists learn is how exciting experiments can be. However, they must also realize science can be dangerous without some instruction on good laboratory practices.

• Read the protocol thoroughly before starting any new experiment. You should be familiar with the action required every step of the way.

• Keep all work spaces free from clutter and dirty dishes.

• Read the labels on all chemicals, and note the chemical safety rating on each container. Read all Material Safety Data Sheets (provided on www.eScienceLabs.com).

• Thoroughly rinse lab ware (test tubes, beakers, etc.) between experi- ments. To do so, wash with a soap and hot water solution using a bottle brush to scrub. Rinse completely at least four times. Let air dry

• Use a new pipet for each chemical dispensed.

• Wipe up any chemical spills immediately. Check MSDSs for special handling instructions (provided on www.eScienceLabs.com).

• Use test tube caps or stoppers to cover test tubes when shaking or mixing – not your finger!

A B C

Figure 1: A underpad will prevent any spilled liquids from contaminating the sur- face you work on.

Figure 2: Special measuring tools in make experimentation easier and more accu- rate in the lab. A shows a beaker, B graduated cylinders, and C test tubes in a test tube rack.

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Good Lab Techniques

• When preparing a solution, refer to a protocol for any specific instructions on preparation. Weigh out the desired amount of chemicals, and transfer to a beaker or graduated cylinder. Add LESS than the required amount of water. Swirl or stir to dissolve the chemical (you can also pour the solution back and forth between two test tubes), and once dissolved, trans- fer to a graduated cylinder and add the required amount of liquid to achieve the final volume.

• A molar solution is one in which one liter (1L) of solution con- tains the number of grams equal to its molecular weight.

For example:

1M = 110 g CaCl x 110 g CaCl/mol CaCl

(The formula weight of CaCl is 110 g/mol)

Figure 3: Disposable pipettes aid in ac- curate measuring of small volumes of liquids. It is important to use a new pi- pette for each chemical to avoid con- tamination.

• A percent solution can be prepared by percentage of weight of chemical to 100ml of solvent (w/v) , or volume of chemical in 100ml of solvent (v/v).

For example:

20 g NaCl + 80 mL H2O = 20% w/v NaCl solution

• Concentrated solutions, such as 10X, or ten times the normal strength, are diluted such that the final concentration of the solution is 1X.

For example:

To make a 100 mL solution of 1X TBE from a 10X solution:

10 mL 10X TBE + 90 mL water = 100ml 1X TBE

• Always read the MSDS before disposing of a chemical to insure it does not require extra measures. (provided on www.eScienceLabs.com)

• Avoid prolonged exposure of chemicals to direct sunlight and extreme temperatures. Immediately se- cure the lid of a chemical after use.

• Prepare a dilution using the following equation:

c1v1 = c2v2

Where c1 is the concentration of the original solution, v1 is the volume of the original solution, and c2 and v2 are the corresponding concentration and volume of the final solution. Since you know c1,

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Good Lab Techniques

c2, and v2, you solve for v1 to figure out how much of the original solution is needed to make a cer- tain volume of a diluted concentration.

• If you are ever required to smell a chemical, always waft a gas toward you, as shown in the figure below.. This means to wave your hand over the chemical towards you. Never directly smell a chemical. Never smell a gas that is toxic or otherwise dangerous.

• Use only the chemicals needed for the activity.

• Keep lids closed when a chemical is not being used.

• When diluting an acid, always slowly pour the acid into the water. Never pour water into an acid, as this could cause both splashing and/or an explosion.

• Never return excess chemical back to the original bottle. This can contaminate the chemical sup- ply.

• Be careful not to interchange lids between different chemical bottles.

• When pouring a chemical, always hold the lid of the chemical bottle between your fingers. Never lay the lid down on a surface. This can contaminate the chemical supply.

• When using knives or blades, always cut away from yourself.

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