STUDENT EXAMPLE

4/17/14

Mr. Olivera

Science 7-2

Science Fair Rough Draft

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Research Question

If I were to make two solar-powered desalination devices, one with a black colored bottom

and one with a white colored bottom, which will be the one to work more efficiently meaning it will

produce fresh water with less salt and at a faster rate? Relating my answer to the principles of heat

transfer.

Background Information

My Science Fair Project revolves around many topics. I am going to create a Solar-Powered

Water Desalination Device that uses many scientific principles. Desalination is a very important term

that has started to make an imprint in the world in the aspect of supplying the over populated world

with fresh water. Desalination is the process of removing a certain amount if not all of salt or other

minerals from saline water. There has been the notion that desalination devices that are supposed to

be able to supply whole cities are too expensive. Unfortunately there is a prevalent predicament for

many places in the world where finding fresh water is a dream that can never be achieved and that

using a desalination device is too difficult to afford. Desalination is a process that if we can find ways

to implement it in cheap ways we can really make a difference for the countries and places that have

low access to fresh water. The device I will be testing out a way that explores scientific terms such as

evaporation, solar power, condensation, surface area, water purity/quality, and the absorption and

reflection of light. This device explores how we can use evaporation accommodated with solar power

using factors such as surface area and heat transfer and transferring vapor and going through the

process of condensation to achieve water purity.

One of the most notable concepts that is referred to and used in this project is the term

desalination accommodated with water purity which essentially is what the device is trying to achieve

or merely the objective. The objective of desalination is an intriguing question. Is it in order to supply

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the human race in all aspects of life not just necessarily meaning survival (for drinking)? So that would

mean things like hygiene and agriculture. There was this notion that dominated most of the world

that desalination was something that world couldn’t prosper as a mainstream maneuver for fresh

water. It was deemed as to expensive. The complex forms of desalination that these devices were

using were too expensive for these poor areas to afford to install in the places with low accesses of

water particularly being fresh water. But this opinion that has been molded into the minds of many is

starting to being changed because we are starting to discover new ways of creating desalination

devices that are cheap and can easily be installed into these struggling places that have difficulty

trying to supply their people with fresh water not just for the sake of surviving because almost living

organisms need water but also for the purposes of the aspects of lifestyle that we mentioned before

such as hygiene and agriculture. Water Purity is another topic that is explored in this project. What

exactly is water purity though. In scientific terms it would be water that is free from all type of

bacteria and viruses and organic and inorganic chemical impurities. So essentially pure water would

be water that is only composed of hydrogen and oxygen molecules which can only exist in a

controlled laboratory environment. Even in an environment like that it would still be hard to create

pure water. Or is water purity based on human needs meaning that water purity is considered to be

when water is at a safe point where it can be used for agriculture, hygiene, and drinking. In that case

it would refer to erasing the bacteria from the water and not the chemical contaminant

concentrations. Fresh water is something similar to the scenario of winning the lottery. In a world

where there is barely enough fresh water to supply the over growing population of not just humans

but all other living organisms is such a surreal task.It is intriguing how a world where 70% of it is water

we only have such a small portion of fresh water. So people are now looking towards the sea to fulfill

their daily basic life needs and a way we can enhance this is by revolutionizing desalination. So in the

world the universal meaning of pure water because of the overwhelming needs of humans is water

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that is safe for humans to drink and use in daily basic human needs.

Another major aspect that the Solar-Powered Desalination Device has is the transitions of the

state of matter particularly when it comes to water. It explores evaporation, condensation, and of

course water vapor. It also explores how certain factors affect the way water evaporates even

mathematical things such as surface area. Evaporation is the process of liquid (mainly referring to

water) turning into its gaseous form and in the case of the desalination being the liquid water the

water turns into water vapor (its gaseous form). 80% of evaporated water comes from the ocean and

the other 20 % comes from inland water and vegetations. Condensation is the process of turning a gas

to a liquid (mainly referring to water) and in the case of the desalination device it is water vapor to

water. Condensation usually occurs when warm air rises to the atmosphere and cools the surface of

the earth so it loses its capacity to hold the water vapor. So it condensates and what happens

afterwards is the following of the precipitation depending on the temperature being snow or rain.

Condensation and Evaporation to concepts that are so close to each other that they can be

considered brother and sister play a very major role in the Solar-Powered Desalination Device that I

am going to create. Evaporation and Condensation are going to be the two maneuvers used that play

a big part in the Desalination of the saline water. The first part of the process of the desalination of

the water is evaporation which plays as a source of transportation. The saline water will be left in a

shoe container or jug and using reflectors and covers around the jug and placing it directly under the

sun we will create an environment where the saline water will be able to evaporate but the remaining

salt will be left in the jug/plastic and clear shoe container. Afterwards the water vapor will travel

through the jug eventually reaching the straw that connects the jug/ shoe container to a small cup

that is wrapped in a special cover/ The water vapor will reach this small cup or container where the

vapor will then condensate back into water but this time into water with less salt to the extent that it

is considered pure water based on human needs. One of the intriguing variables that will affect the

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rate at which the saline water evaporates which affects the rest of the process is the surface area of

the jug where the saline water will be placed. It is a proven statement that a larger surface area will

quicken the rate of evaporation so it will be vital for the saline water to be placed on the side of the

jug/shoe box plastic container with the largest surface area.

Another two essential concepts that are explored in my project are the absorption and

reflection of light and heat transfer. Light absorption is when a light wave with a given frequency

strikes a material or object with electrons of the same vibrational frequencies. The electrons will

absorb the energy of the light wave and transform it into vibrational motion. During the vibration the

electrons interact neighboring atoms which convert the vibrational energy into thermal energy.

Consequently the light wave is absorbed by the object and will never again be released in the form of

light. Light reflection is when light waves strike an object and its frequencies do not match the natural

frequencies of the vibration of the object. When light waves of the given frequencies strike the object

the electrons will start vibrating but not in resonance at a large amplitude but instead the electrons

will vibrate for a short amount of time then stop and then vibrate for a short amount of time and

continue the cycle. Finally the energy is re emitted as a light wave. Heat Transfer is when thermal

energy is transferred from an object of high temperature to an object with low temperature. Usually

during heat transfer the internal energy of both objects involved in the process change. There are

three types of main heat transfer. The first is radiation. Radiation the transfer of heat through

electromagnetic waves. Convection is another form of heat transfer. It is when there is mass motion

of a fluid such as air or water when it is caused to move away from the source of heat carrying energy

with it. Another type of heat transfer is conduction. It is heat transfer by the means of molecular

agitation. It is within a material without any motion of the material as a whole. The absorption and

reflection of light and the heat transfer are important parts in the Solar-Powered Desalination Device

because they play important roles in quickening the evaporation by bringing heat. Heat Transfer from

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the sun plays an important role in creating an environment where the saline water can evaporate

quickly and so does the absorption and reflection of light.

Hypothesis: I believe that if I test two solar powered desalination devices, one with a black colored

bottom and one with a white colored bottom, and place them in the same area at the same time and

leave them there for four hours the one with a black colored bottom will produce more fresh water. I

believe this because the black colored bottom will absorb the electromagnetic waves from the sun

and turn them to heat consequently evaporating the saline water faster. While the difference

between the black colored bottom and the white colored bottom is that the white colored will reflect

the light relating to the concept of light reflection in which the white colored bottom and the

electromagnetic waves from the sun are a perfect example of light reflection.

Variables

Independent Variable- The bottom of the solar powered desalination devices (the type of

construction paper used for the bottom of the solar powered desalination device).

Dependent Variable- The amount of water that is desalinated.

Control- The type of water used, and the same device used.

Materials . A device that is able to time something . 40 ml graduated cylinder . measuring tablespoon . Iodized Salt (50g) . 500 ml measuring cup . 100 ml graduated cylinder . access to clean water . white construction paper (3 sheets) . black construction paper (3 sheets) . Rubber bands (2) . metal washers 6/17 inch size . disposable plastic cups (2) . plastic cling wraps . tape . modeling clay . scissors .flexible plastic straws (4)

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. clear plastic shoeboxes (2)

. small funnels (2)

. hand drill with 5/16 or ¼ drill bit Procedure In this Part of the Process each step is done twice because you are making two desalination devices. Step 1: Use your hand drill to form 2 holes on the side of the clear plastic shoebox that is relatively a small size that is big enough for a large straw to fit through with some moving space. Step 2: Take a funnel and connect to an end of the short side of the bendable straws. Make sure the funnel does not stick up too far. The short ends of the straws should be cut with scissors. Step 3 : Put the straw funnel assembly through the holes that have been drilled through the bottom of each container. Next prepare the two cups for each desalination device. Drill 2 small holes of the same size into the side of the cups near the bottom. Make sure the holes are lower than the holes of the container so the straw can slope downwards. Step 4: Next put the empty side of the straws into the holes of the small cups. Make sure it adjusts to slope downwards and not stick out in any awkward way. Step 5: Put some modeling clay around each hole to secure the firmness of the straw’s side that is entering the hole. Step 6: Cover the opening of each container with cling wrap. Step 7: Place a metal washer over the middle of the cling wrap over the container. Adjust it so the metal washer creates a low point in the cling wrap. Step 8: Cover the outside of the bottom of the container with black construction paper for one and white construction paper for the other. Step 9: Make a single batch of salt water for each container. First you shall pour water till it barely covers the bottom of the container so you can know how much water you need. Then for every 500 ml of water you pour add 17.5 grams of salt. Step 10: Carefully take your desalination device outside where there is direct access to sunlight. Step 11: Prepare your device is ready for testing and make sure that everything is in place and ready. Step 12: Check the desalination device every thirty minutes. Step 13: Stop Your testing after the desalination device has been in the sunlight for at least four hours. Step 14: Open the cling wrap and try to get any other remaining condensate out by gently blowing the straw. Step 15: Determine the amount of condensate by pouring it into a measuring cup.

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Step 16: Measure the salt remains. Data Saline Water Testing- After finding out how much water and salt I would need to make the appropriate amount of saline water for the device to test out using a formula I have concluded that I will need 250 ml of water and 8.75 g of salt. Introduction

I will now start the actual testing of my end of the year Science Fair Project. Due to unfortunate

circumstances I live in an apartment building therefore I cannot put my device in public outside

property for safety reasons. I was forced to put the device in my dad’s car but on the other hand the

car is in a good area near the sun. Due to the inconsistent weather throughout the day especially with

the sun coming out fully partially and sometimes nowhere to be seen behind the clouds I am not

expecting great results for this device meaning a surplus of water desalinating. I will check the device

every 30 minutes for four hours till I finally terminate the device. I will test two devices for each trial.

One with the white colored bottom and one with a black colored bottom. I will do three trials and

then when I finish conducting each trial I will measure the water that is still in the container, the water

desalinated, and then calculate the water that has evaporated and not fully gone through the whole

desalination process. I will not make numerical observations between the process because I cannot

measure the desalinated water when it is in the process but I will take pictures.

Day 1- Trial 1 May 25th 2014 Saline Water Temperature: The average temperature between the two batches of saline water for each device is around 108 degrees fahrenheit. One is 110 degrees fahrenheit and the other is 107 degrees fahrenheit. The outside temperature which is where the experiment is taking place is seventy six degrees fahrenheit. But I will record the temperature for every thirty minutes. Thirty Minutes in In the first thirty minutes so far I have see no condensate or drops on the washer. In essence I have not seen any clues yet that this device is working as its supposed to but perhaps I am being impatient and I need to give the device more time since it is four hours of sunlight that the device will have to go through. I have also noticed that the funnels are starting to slope downward because of the awkward position of the desalination device. But there is a good thing I have picked up from observing the water desalination device which is that it is extremely hot in the car. It feels hotter in there compared

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to the actual outside which I see as a good thing. Perhaps this extreme heat will affect the rate of evaporation. In terms of comparing the black colored bottom device and the white colored bottom one they are pretty similar in all aspects. One hour in In the second thirty minutes the temperature has risen to 80 degrees fahrenheit. Not much has changed from the previous thirty minutes. The top surface of the container which is the cling wrap does not have any signs of condensation or evaporation except for the area for where the metal washer is. Astoundingly enough the white colored bottom looks like the one that is working better because there are more evaporation and condensation drops on the sides of the container unlike the black colored bottom one and it looks like there is less water in the container for the white colored bottom One Hour and Half in There has now been a major change in the black colored bottom device and the comparison between the two devices. There are now a lot of condensation drops on the surface of the black colored bottom device. Literally every single square centimeter has a condensation drop. It is astounding compared to the white colored bottom which hardly has any condensation drops on the surface. It is still 80 degrees right now outside. There is still no desalinated water in the cup. I am starting to worry that the funnel aiming downwards is the reason the water has not been able to travel through the straw and become desalinated. It is definitely something i have to think about in my next trial. Two Hours in The next thirty minutes there has not been a lot of change but I have noticed that there has been a lot of water that has evaporated but there is still no fully desalinated water which I am kind of worrying about. On the other hand it is getting windier but the temperature has risen to 81 degrees fahrenheit. Two Hours and a Half in In the next thirty minutes hardly anything has changed. I’m starting to seriously doubt that this trial will have any results in terms of desalinated water because of the funnel sloping downwards. But I will say that this is still not a fail in general because the whole objective of this project is to see which desalination device will work better and I am getting telling results. Temperature is the same. Three Hours in I have realized that this trial will ultimately not be a success because of the way the funnel and washer have been set up. The funnel was supposed to be facing up and directly under the the washer but during the first thirty minutes because of the awkward position of the device the funnel started to drastically slope downwards. But the evaporation process of the device has definitely been a success. A lot of the water from both devices have evaporated but the black colored bottom evaporated at a quicker rate and has less remaining water. Three Hours and a Half in Nothing really has changed at all. Four Hours in In the final thirty minutes not much has happened. I have measured the amount of water left. For the black colored bottom device there was 200 ml of water left meaning that 50 ml evaporated. For the white colored bottom 235 ml of water was left meaning that 15 ml evaporated. Based on my hypothesis I was correct and especially would of been if the funnel stayed adjusted. Day 2- Trial 2 May 31rst 2014 Due to unexpected results in my first trial I have made a lot of changes to my project that I am looking forward to since I believe they will give me better results. I studied the first desalination device I used and I realized that the washer and the funnel being coordinated. My funnel had fallen and started to slope downwards. I think the main reason for this was that I did not correctly measure the holes of the plastic cup and container to make a certain angle for the funnel to stand up. I have also changed

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the location of the device to speeden up the the process. I am so fortunate to do the next two trials at my uncle’s house in which I can place my device outside where there is direct sunlight. I bought new containers that hold relatively the same water so I can form new holes that will let the funnel slope upwards towards the washer. Thirty Minutes in The first thirty minutes have given me splendid results. It is 65 degrees fahrenheit outside as of right now. A lot of water has evaporated and there are an abundance of water drops on both desalination devices top surfaces. It as gone as far as the fact that there are drops of condensation on the funnel of the white covered desalination device. Both are doing well so far and I hope for more results that help. One Hour in The second thirty minutes have been similar to the first thirty minutes in the sense that there is a lot of evaporation and there are tons of condensation drops. The drops are starting to move towards the washer so then they will eventually drop into the funnel. So the devices right now are working properly. To be honest since I can’t record any numerical data right now I can’t determine which device is working better because there is no visual indication. The temperature has risen to 67 degrees. I am a bit worried that because the devices are standing in an uneven fashion because of the grass this will prevent more water drops from traveling to the washer and then consequently to the washer. One Hour and a Half in The third thirty minutes have been great. I have seen the condensation travel through the straw. Although the only problem is that the entrance of the straw inside the funnel in which the condensation goes through is surrounded by play doh so the condensation is getting remains of play doh inside it which is making it harder for the condensation to fully travel through the straw. The black colored one has more condensation sitting in the straw. I think for the next trial I might need to find a better way for the condensation to fully travel through the straw. The temperature has risen to 68 degrees and it is becoming windy. Two Hours in The fourth thirty minutes have been decent. I have seen the condensation drops move towards the washer and more drops are falling into the funnel. But the water in the straw still isn’t moving. The temperature is still the same. Two Hours and a Half in The water has finally fallen into the cup. But this has only happened for the black colored device. For the white colored device on the other hand nothing has really happened. There are still tons of condensation drops though and there is a tiny portion of water in the straws. Three Hours in In the sixth thirty minutes not much has happened. The water in the cup of the black colored bottom device is evaporating and condensing. While the white colored bottom has failed to have water in the cup yet. Three Hours and a Half in In the seventh thirty minutes there was a small amount of drops that went into the cup for the white colored bottom otherwise everything else was normal and not much has changed. Four Hours in In the eighth thirty minutes I have found and concluded that for this trial the black one ultimately did better. In numerical form the black one had 70 milliliters of the 250 evaporated and condensed while 10 ml went into the cup. While for the white colored bottom 20 ml of water evaporate and 2 ml went into the cup. Day 3- Trial 3 June 1rst 2014

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For the third trial I will be going back to the old habitat I used for the first trial. One of the changes I have made is that I put more attention on the straw’s slope downwards so the water can flow easier. Thirty Minutes in So far for the first 30 minutes of the trial not much has happened. There are some condensation drops on the top surface of the black colored bottom device. But for the white there is probably only a few. This observation is supporting my hypothesis. It is 75 degrees as of right now. There are no drops are neither funnels of each device. One Hour in The next thirty minutes have showcased lots of change and lots of progress for the desalination device. There are now tons of condensation drops on the black colored bottom. The temperature has risen to 77 degrees fahrenheit. Since the metal washer has created a low point in the cling wrap forcing the water to move downwards to the center of the wrap where the washer and the funnel are, there are lots of drops of water on the funnel for the black colored bottom. There are a lot of condensation drops for the white colored bottom device but not as much as the black and there are a few drops in the funnel. One Hour and Half in The next thirty minutes have had a small amount of change. There are a tiny few drops of water for the black colored bottom device that are in the straw while there are more drops of water in the funnel. The temperature has stayed the same. For the white colored bottom device there are more drops on the surface and there is progress in which the drops are coming to the center of the cling wrap and falling onto and into the funnel. So there are a few drops on the funnel. Two Hours in In the fourth thirty minutes there have not been that much change mimicking the way the third thirty minutes fared out. On the other hand I see more drops on the funnel of the black colored bottom device. But in the straw I have not seen change. On the other hand for the white colored bottom device there is not that much change either. The temperature has dropped one degree to 76. Two Hours and a Half in In the fifth thirty minutes there have been breakthroughs for both devices. There is some water in the cup of the black colored device and there is some water slowly going through the straw. For the white colored device there is also a tiny amount of water in the cup and there is also a tiny amount of water in the straws. The temperature is the same. I shall also mention that it is brutally hot inside the car explaining the good results. Three Hours in The sixth thirty minutes have mimicked the fifth thirty minutes. The temperature has dropped to 75 degrees fahrenheit. There is more water in both cups. Three Hours and a Half in In the seventh thirty minutes not much has happened. You can visually see there has been an increase of water in the cup for the black colored bottom device but I am unable to see for the white colored device. The temperature has not changed. Four Hours in In the eighth thirty minutes I cannot visually see any change. I have taken the devices back inside to check on them and record my numerical observations. I have recorded that for the black colored bottom one 75 milliliters of water evaporated but only 35 milliliters fully desalinated. For the white colored bottom one 24 milliliters of water evaporated but only 11 milliliters fully desalinated. This trial has been a success and proven my hypothesis right.

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Graph 1

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Graph 2

Conclusion

My conclusion to this experiment is that it has been a total success. All my trials gave me telling

results that I could draw conclusions from. Although at some points I had trouble building the

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desalination device I got through with it and successfully built one that worked. The first one I was not

happy with because of the hole coordination and the straw funnel assembly but I though I did a

decent job for the device I would use for the next two trials. My hypothesis was correct which I am

glad about. For all three trials I got results that were in favor of my hypothesis that the black colored

bottom device would work more efficiently. For trial one although I did not produce any fully

desalinated water the black colored bottom one did have more evaporate water and for the next two

trials the black colored bottom device just outright produced more desalinated water and had more

evaporated water. This was because the black colored bottom one was able to absorb the

electromagnetic waves from the sun and to keep it which gave the device more heat which

consequently led to more efficient evaporation and subsequently desalination. While the white

colored one did the exact opposite which was reflect the light. Not only did it not keep the heat but it

reflected light rays of the sun which were the source of heat to form evaporation and subsequently

desalination.

Further Discussion If somebody were to further look into this experiment and conduct one for a project I’d definitely

want to make some upgrades to help the device work better from first hand experience. I think the

most vital change would be to have two funnels and two washers for one device. I would put the two

washers directly next to each other in the center so they would create a larger low point. Then out the

two funnels connected to the straws and cups would lay directly under the washers. I would also

make sure that the holes are precisely cut or drilled so it would create a perfect slope for the straw

funnel assembly. If you were to take this project and make it a serious project that could be used for

actual cities the size of the device would be to a larger degree. But more so there would be more

funnels or whatever source they would use to bring in the condensation rather than just one funnel. I

would also try to find a way to attract more sunlight or create some source of heat maybe through a

large fire or increasing the room temperature so it would speed and make the desalination process

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better. If this device were to be a real thing my visualization of it would be multiple giant transparent

tanks filled with saline water. There would be multiple funnels connected to metal tubes inside these

tanks. The tubes would connect into these smaller tanks. So the water would evaporate and the

condensation drops would go into the funnels and travel through the metal tubes and into the smaller

tanks. The one thing I would go back and do for my experiment would of been to check the devices

with more awareness to make sure that everything would be ready for testing.

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Science Fair Bibliography Research Paper:

1. "Solar Power Energy Information, Solar Power Energy Facts ­ National Geographic." 

National Geographic. National Geographic Society, 2014. Web. 17 Apr. 2014. 

<http://environment.nationalgeographic.com/environment/global­warming/solar­power­profile/>

.

2. Toothman, Jessika. "How Does Desalination Work?" HowStuffWorks. HowStuffWorks.com, 

06 Oct. 2010. Web. 17 Apr. 2014. 

<http://science.howstuffworks.com/environmental/earth/oceanography/how­does­desalination­w

ork.htm>.

3. "WHAT DOES WATER PURITY REALLY MEAN?" Water Quality Information. APEC, 

n.d. Web. 17 Apr. 2014. 

<http://www.freedrinkingwater.com/water_quality/quality2/j­22­08­water­purity.htm>.<http://w

ww.freedrinkingwater.com/water_quality/quality2/j­22­08­water­purity.htm>.

4. Wilhelmson, Bob, and Mohan Ramamurthy. "Evaporation: The Conversion of Water from a 

Liquid into a Gas." Evaporation: The Conversion of Water from a Liquid into a Gas. Department 

of Atmospheric Sciences (DAS) at the University of Illinois at Urbana­Champaign., n.d. Web. 17 

Apr. 2014. <http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/hyd/evap.rxml>.

5. "Weather Questions & Answers." Weather Questions. WeatherStreet.com, 2013. Web. 17 

Apr. 2014. <http://www.weatherquestions.com/What_is_water_vapor.htm>.

6. Wilhelmson, Bob, and Mohan Ramamurthy. "Condensation: The Conversion of Water from a 

Gas into a Liquid." Condensation: The Conversion of Water from a Gas into a Liquid. 

Department of Atmospheric Sciences (DAS) at the University of Illinois at Urbana­Champaign, 

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n.d. Web. 02 June 2014. 

<http://ww2010.atmos.uiuc.edu/%28Gh%29/guides/mtr/hyd/cond/home.rxml>.

7. "What Affects the Rate of Evaporation of Water." All Science Fair Projects. N.p., 2013. Web. 

17 Apr. 2014. <http://www.all­science­fair­projects.com/print_project_1097_58>.

8. "Light Absorption, Reflection, and Transmission." Light Absorption, Reflection, and 

Transmission. © 1996­2014 The Physics Classroom, n.d. Web. 27 Apr. 2014. 

<http://www.physicsclassroom.com/class/light/u12l2c.cfm>.

9. Nave, R. "Heat Transfer." Heat Transfer. N.p., n.d. Web. 30 May 2014. 

<http://hyperphysics.phy­astr.gsu.edu/hbase/thermo/heatra.html>.

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