Brainstorming About Blades

Variables There are many variables that affect wind turbines or any other machines in general. A variable is a value or property that may change in an investigation. When conducting an investigation, you should only test one variable at a time (independent variable). That means you have to control all of the other variables to the best of your ability.

Brainstorming About Blades What do you think makes one turbine work better than another? What variables affect the amount of power a turbine can generate? Do some variables matter more than others? (For example, is turbine height more important than the number of blades?) What do the blades of modern wind turbines look like? Is this similar to older windmills? Why? How many blades do most wind turbines have? What do you think would happen with more or fewer blades?

Blade Design Variables What are some variables that we can test with our turbines? Other ideas: – Number of blades – Weight of blades – Pitch/Angle of blades – Shape of blades – Blade material – Twist or not to twist/amount of twist

List the items you will need to make your blades. Decide who will bring which items from home. You will need to bring them on Tuesday. To make sure our results are accurate, lets take the average (mean) of three different measurements for each test. For example, if I am testing the length of the blades, I would test my shortest blade three times and take the average, then test my medium blade three times and take the average, and then test my longest blade three times and take the average. The averages will be used to graph the results. If we want to compare results between groups (yes, we do!) we all need to take our measurements at the same time interval. Let’s decide how long we should let the blades spin before we take the data reading. (ie. 20 seconds, 15 seconds, 30 seconds????)

This will be different for each group. Be specific. For example, if you are testing the effect of blade pitch, you will tell the angles at which you are going to test. We are testing blade pitch. We will test three different angles: 30⁰, 60 ⁰, and 90 ⁰ angles. We are testing the length of blades. We will test blades that are _________ long, ________ long, and __________ long. We are testing different shape of blades. We will make all of our blades __________ long but we will change the general shape of the blades. The shapes we will do are: (draw your shapes here) We are testing how the number of blades affects the electrical output. We will test with ____ blades, ______ blades, and _______ blades. (maximum of 6 blades) We will use the data loggers as multimeters and record in volts.

Start Designing… Use the information from your planning sheet to design your blades based on the variable you are testing. Remember that you can only change one property (length, material, weight, etc.) and all of the other variables have to be the same. You will be called up one group at a time to explain your project to your teacher.