About how long would it take to do a project on....

[Sasha317]

wind power being converted into electricity? I want to try and include a model of a windmill that will power a lightbulb. Can you help me?

[agm]

Hi Sasha317,

Welcome to the forum! Exactly how long a project will take depends on what you decide to do, and you can keep the due date in mind when designing your experiment. Three months is a nice amount of time -- especially if you jump right into background reading and thinking about an interesting hypothesis and how to investigate it, you should have time to cushion any difficulties in carrying out your experiments.

In case you haven't seen our project guide, it might help you develop your experiment:

https://www.sciencebuddies.org/science- ... ndex.shtml

You seem to be at the stage where you've identified a topic of interest and need to come up with a question you want to answer through your investigation. If you are interested in something like whether design A or design B produces more power and decide to build small versions of those wind turbines, then you'll definitely have something to connect to a lightbulb and place in front of your project display board. Even if you decide to go in a different direction that doesn't require building one, there is information out there to help you build your own model as a demo if you have time.

For now, I'm going to point you to some resources for background reading, and I hope you'll post again with the ideas you come up with and any questions you have.

About wind turbines:
http://science.howstuffworks.com/wind-power.htm
http://www1.eere.energy.gov/windandhydro/wind_how.html
http://books.google.com/books?id=4UYm89 ... ry_r&cad=0

People who've built their own wind turbines:
http://www.unpluggedliving.com/top-5-ho ... tructions/
http://www.alton-moore.net/wind_turbines.html

Very brief outline of a project idea:
https://www.sciencebuddies.org/science- ... o&from=TSW

Best wishes,
Amanda

[MFagan]

This sounds like an excellent project given the need to educate people about alternative energy sources!
You're already very much on the right track by deciding to build a scale model. One of the nice things about wind turbines is that they are fundamentally electric airplanes running in reverse. They have a propeller of some form which converts the wind energy into rotational energy, coupled to a generator, which turns rotational energy into electrical energy with the same method as an electric motor. In fact, if you haven't already discovered through your research, a generator is simply a motor running in reverse. What this means in terms of your project is that you can use simple electric and mechanical components, perhaps designed for model airplanes, and build a simple wind-powered generator. This can power a small lightbulb. In addition, I would recommend that you also take quantitative measurements, such as voltage and current, as well as demonstrating the electrical power of the turbine by powering something (what we would call the "load" in the circuit).
Once you have some measurements, you can compare the results from your wind turbine to those of commercial turbines, as well as to other sources of electrical energy. One statistic to look for is often known as "well to wall" efficiency, and looks at the entire energy generation process, from the source (oil, gas, or coal in conventional power plants [the "well"], wind or sun would be alternative examples) to the consumer (the "wall"). This allows easy comparisons across different types of energy sources.
Feel free to ask additional questions as you develop your project further
Good luck
Michael

[Sasha317]

Thank you both so much! You gave me even more information then I asked for, and I will most definatly come back should any other questions arise.

[Sasha317]

I'm not entirely positive what a good question for this would be....would How Much Windpower Would it Take to Power a Modern American Home be irrelevent? (yes I know its extemly long, and if it will work I'll shorten it haha)

[Sasha317]

How about Which Type of Windmill would Power the Average American Home Best?

[agm]

Sorry I missed your question a few days ago!

I'm not entirely positive what a good question for this would be....would How Much Windpower Would it Take to Power a Modern American Home be irrelevent?
How about Which Type of Windmill would Power the Average American Home Best?

Well, it depends on the kind of project you want to do:

1. You might want to define an "average" home, since there's a lot of variation in geography (how often there is wind and how strong), building regulations (some kinds of windmills only work well when they are very high in the air), power usage (e.g. from different heating and cooling needs), and other important factors across the country. For example, there would be a big difference in the kind of windmills best for someone living in an apartment in NYC with access to a few square yards of roof space vs. someone living on a farm in the midwest with many acres of land. Determining this would require things like looking up numbers in tables and reports, maybe some statistical analysis, etc. You could determine a set of criteria that the windmill should fulfill and then investigate available kinds of windmills to see which fits your criteria best, with or without actually physically building a few and testing them. Especially if you did this without testing windmills yourself, this would be more of a social science experiment than a physical science experiment -- and it would be a totally valid (depending on your teacher's/science fair's guidelines) and very important project. If you decide to go this way, we could ask the moderators to reclassify this thread into the Life/Earth/Social Science forum so that those experts will see it (though I would of course still follow it).

2. You could look at published work to find a ready-made definition of an average home or use the parameters of your home. Then you could look at information about windmill designs, decide on several as the best candidates, and form a hypothesis regarding which type would work best. Then you could build models and test them. (For this and #1, you might find that it makes more sense to break "average home" into subcategories like "average urban home", "average rural home", "average apartment", etc.)

3. You could reduce it to a really basic scientific question framed independently of applications like does design A, B, or C produce the most power under wind speeds of 5, 10, and 15 mph? Then you could form a hypothesis, build these models and test them under whatever circumstances you have specified (wind speed of course isn't the only independent variable possible).

All of these types of investigations have value. In my experience, most of the time a typical physical scientist would look at studies of type 1, or even review articles summarizing these types of studies, to get an idea of what kinds of windmills (or widgets, or whatever the subject of interest is) would be most valuable to society. Then he or she would design an experiment of type 2 and apply for grants, citing studies of type 1 to show that the work is not just of scientific interest but also of potential value to society. Then when the work is published, he or she would again include some information from type 1 studies to explain why the work is important. However, many (if not most) physical scientists relish the opportunity to do 'basic research', investigating questions of scientific interest while unencumbered by practical considerations. The societal value in these type 3 experiments is pure knowledge as well as the off chance that a really awesome application could arise from something that's discovered (if you are interested, I can dig up some examples of this for you later). For example, imagine that everyone doing type 2 experiments was investigating windmills no taller than 20 feet because building regulations prohibited taller structures. But if someone did a type 3 experiment that indicated that a 100-foot-tall windmill would produce 1000 times as much energy, people would become very interested in changing those regulations.

(FYI, I just made up these 'type 1-3' classifications to clarify your options, so I wouldn't recommend googling that terminology.)

So, what kind of experiment are you most interested in? I would recommend thinking about what you want to spend your time doing and what questions you are most interested in answering for yourself, and then definining a specific question and coming up with a title.

Amanda

[Sasha317]

thank you Amanda! I will definatly consider these options, and talk it over with my teacher to see what kinds of rules/regulations there are since this is the first science fair project i plan to create. I'll get back to you as soon as i can!

[Sasha317]

Ok, so I talked my options over with my teacher, and she agreed that it would probabaly be best if I stuck with a basic question. I've decided to go along the lines of what you suggested Amanda. What Type Of Windmill Blade Will Produce The Most Electricity Under Wind Strengths of 5, 10, and 15 MPH? I've determined that I will build at least 3 different types of blades, but would it/would it not be okay for me to build one windmill and make it so i can just change the blades out? If I can't then I'll have to buy/build 3 generators (which will probabaly be really expensive!)

~Sasha
P.S. Thank you so much for helping me!! ^^

[Craig_Bridge]

It is VERY HARD to build three identical units (except for the blades). Typical manufacturing and construction tolerances will cause unit to unit variations which maybe significant if two of the blade designs you choose have similar performance characteristics. When comparing things scientifically, you want to minimize unintended differences. For this reason alone, you WANT to utilize as much of the same unit as you can and only switch out the blades and whatever else you need to adapt them to the unit.

In order to be fair in the comparison of different blade designs, you need to consider the generator efficiency and the diameter of the blade assembly. Generators typically have some performance curves that involve rotational speed and torque required vs power generated. You also need to consider the area of wind that your different propellers can interact with. The volume of air moving through a 12 foot diameter circle will be greater than the volume of air moving through a 10 foot diameter circle.

Engineers often place some "cost factors" on a design in order to compare designs. If you come up with an extremely efficient propeller design that costs 100 times the cost of a simpler design that is 10 percent less efficient, it maybe less expensive to build two of the lower cost units. In other words, you need to think about what your judging criterion is going to be to determine your best blade configuration.

[agm]

Hi Sasha,

I'm glad it sounds like you've narrowed down your project and are happy with it. One thing I should add on top of Craig's excellent comments is that when I suggested 5, 10, and 15 mph, I was really just throwing out an example and made up numbers to make it concrete. You should look into what wind speeds are like, perhaps in your area and perhaps in areas that are considered ideal for wind power. You might be somewhat limited by the maximum output of the fan you use -- you could build an anemometer and test any that you have around the house to see if it will be important to find a more powerful one. I really don't know what the answer will be here. We have an easy project that describes how to make an anemometer -- I'm not sure if this will be accurate enough for the final project, but it might give you an idea of what you're working with for planning purposes.

https://www.sciencebuddies.org/science- ... p008.shtml

Even though your independent variable is actually the blade, testing each blade at a set of different speeds is important because wind speed isn't constant over time. In some places, most available power might be in the form of consistent gentle breezes, while in others it might be in the form of intermittent gusts -- so the best blade might be different in these cases. You could also say that in your model location, 20% of the available energy is at speed 1 and 40% is at speed 2, etc, and you could weight the efficiencies at the different speeds accordingly to find out which blade would be best overall. You can get started reading about this here:

http://en.wikipedia.org/wiki/Beaufort_scale
http://en.wikipedia.org/wiki/Wind_Power ... wind_speed

If you want to find real numbers for different locations, you might be able to get them from the National Climatic Data Center, assuming you're in the US:

http://www.ncdc.noaa.gov/oa/ncdc.html

I actually took data from here and analyzed it for my 9th-grade science project, and at the regional fair I got to meet the meteorologist from a local TV station!

Amanda

[Sasha317]

It is VERY HARD to build three identical units (except for the blades). Typical manufacturing and construction tolerances will cause unit to unit variations which maybe significant if two of the blade designs you choose have similar performance characteristics. When comparing things scientifically, you want to minimize unintended differences. For this reason alone, you WANT to utilize as much of the same unit as you can and only switch out the blades and whatever else you need to adapt them to the unit.

In order to be fair in the comparison of different blade designs, you need to consider the generator efficiency and the diameter of the blade assembly. Generators typically have some performance curves that involve rotational speed and torque required vs power generated. You also need to consider the area of wind that your different propellers can interact with. The volume of air moving through a 12 foot diameter circle will be greater than the volume of air moving through a 10 foot diameter circle.

Engineers often place some "cost factors" on a design in order to compare designs. If you come up with an extremely efficient propeller design that costs 100 times the cost of a simpler design that is 10 percent less efficient, it maybe less expensive to build two of the lower cost units. In other words, you need to think about what your judging criterion is going to be to determine your best blade configuration.

Thank you Craig! you have helped clear up my issue I just wasn't positive weather or not I would be allowed to change the blades.You have also made some points that will definatly help me when building my windmills.

Hi Sasha,

I'm glad it sounds like you've narrowed down your project and are happy with it. One thing I should add on top of Craig's excellent comments is that when I suggested 5, 10, and 15 mph, I was really just throwing out an example and made up numbers to make it concrete. You should look into what wind speeds are like, perhaps in your area and perhaps in areas that are considered ideal for wind power. You might be somewhat limited by the maximum output of the fan you use -- you could build an anemometer and test any that you have around the house to see if it will be important to find a more powerful one. I really don't know what the answer will be here. We have an easy project that describes how to make an anemometer -- I'm not sure if this will be accurate enough for the final project, but it might give you an idea of what you're working with for planning purposes.

https://www.sciencebuddies.org/science-f ... p008.shtml

Even though your independent variable is actually the blade, testing each blade at a set of different speeds is important because wind speed isn't constant over time. In some places, most available power might be in the form of consistent gentle breezes, while in others it might be in the form of intermittent gusts -- so the best blade might be different in these cases. You could also say that in your model location, 20% of the available energy is at speed 1 and 40% is at speed 2, etc, and you could weight the efficiencies at the different speeds accordingly to find out which blade would be best overall. You can get started reading about this here:

http://en.wikipedia.org/wiki/Beaufort_scale
http://en.wikipedia.org/wiki/Wind_Power ... wind_speed

If you want to find real numbers for different locations, you might be able to get them from the National Climatic Data Center, assuming you're in the US:

http://www.ncdc.noaa.gov/oa/ncdc.html

I actually took data from here and analyzed it for my 9th-grade science project, and at the regional fair I got to meet the meteorologist from a local TV station!

Amanda

Thank you once again! The 'staff' here is definatly proving to be waaaaay more helpful then I expected haha. I didn't know that there was a National Climatic Data Center! That should be very helful! Are you saying not to test the blades at the same wind speeds?

[agm]

Are you saying not to test the blades at the same wind speeds?

Definitely not -- I apologize that that was unclear! So, as you probably know, experiments usually only have one independent variable, and everything else is kept constant. If you are primarily interested in different blade designs, that would suggest that the blade type would be your independent variable and that wind speed (and everything else relevant that you can possibly control) would be kept constant. However, there is a good reason to use a set of several wind speeds: wind doesn't blow at the same speed all the time. Some of the pages I linked before suggest that even if it blows at a low speed most of the time, the brief periods of high speed often contain more total energy than the long periods at low speeds -- so in a realistic setting, the "best" blade could be defined as something like (a) the one where the efficiency at a given speed times the energy available at that speed is maximized, (b) the one where (available energy at speed)*(efficiency at speed) is summed over each speed you try, weighted by the relative prevalence of the speeds, (c) a definition that you create. So, if you don't want to mess with multiple wind speeds, it might be a good idea to find out at what speed the most energy is available -- perhaps in your area, perhaps in a place where windmills have been built, perhaps some kind of average. If you are interested in doing multiple wind speeds, you most definitely want to try the same set of speeds for each blade design. A logical next step (in parallel to researching blade designs) might be to find out what realistic wind speeds are and what you'll be able to get from fans available to you.

Amanda

[Sasha317]

Oh ok I see what you mean now! I just got a little confused haha.

[Sasha317]

I have officially finished my project! I kept it simple and only used:
PVC pipe
An old flashlight (the kind that you turn the handle to light up)
Bionical toy parts
a peice of scrap wood
2 different plastic exhaust fan blades (both 6 inch, different number of blades on each)
Some old telephone wire
Cardboard (made a little house! haha)
Superglue
paint
and of course a whole lot of my dads power tools haha.

I will post what I did later so others can maybe learn form my mistakes.