Wind Turbine

Wind turbines rely on...
   Electromagnetic induction: electromagnetic induction happens when a magnet moves through coils of wire. This changes the magnetic field of the wire which induces voltage which makes current which results in electrical energy. We used this concept to create a generator.
   Newtons first law: objects in motion stay in motion unless acted on by an outside force. This concept was useful because the blades stayed at rest until turned by the wind and would keep going if there was minimal friction. Because of this we tried to make as little friction as possible.
   Newtons second law: a=f/m. The acceleration of the wings equals the force divided by the mass. The more wind, the faster the blades spun. The more mass the wings had, the slower the blades would spin. It was important to have light blades because of this.
 
The materials we used were...
   cut up water bottles for blades to catch the wind and spin.
   dowels to hold the blades onto the machine.
   a metal rod to connect to the blades and spin the generator.
   magnets to attach to the metal rod so they can spin and create electromagnetic induction.
   coils of wire so when the magnets spin they create electromagnetic induction by changing the magnetic field of the wires which induces voltage which induces current.
   cardboard to keep the generator together and to use as a base to hold up the turbine.

Blades held on with dowels.

Machine held up by cardboard base.

Metal dowel to connect to blades and magnet.

Cardboard box containing generator. 

Coils of wire to make electromagnetic induction. 

Generator.

Coils of wire

Magnet spins when metal dowel is spun by blades.  

Our turbine.

Results...

   we generated .008 volts and .005 amps but were not able to light a lightbulb because we did not make enough because our blades didn't spin fast enough because there was too much friction. 

   Overall, our design worked very well. Our blades caught wind, our base was sturdy, and we had a good generator design. Our main problem was having too much friction. If we had more time, we would make the box big enough so that the magnets didn't scrape the sides of the box. 

   Our group worked very well together and I think the best thing that we did was making a very thorough plan instead of jumping right into building. 

 

Top Ten Places You Can See Physics At The State Track Meet

Over the weekend I went to the state track meet and saw a whole lot of physics!...

1. We drove to the meet in a bus. The bus is powered by a motor. The motor is supplied voltage from a battery which supplies current. The magnet supplies a magnetic field that makes charges move. The wires spin as a result of this current. The motor functions because there is a current carrying wire that feels a force from the magnets magnetic field and a torque is caused.

2. At the meet when people crossed the finish line they kept running for a bit before they slowed down. This is because of Newtons First Law which states that objects in motion stay in motion unless acted on by an outside force. In this case the runners are moving very fast and their bodies want to continue to do so. Because of this, even though they have crossed the finish line they keep going foreword while creating a lot of friction on the track until they stop.

The girl on the left is still running. 

I have crossed the finish line but continue to move

Emma has finished and stopped moving.

3. At the meet, people compete to see who can run at the fastest speed. Speed is the measure of the distance an object, or in this case a runner, travels in a designated amount of time. For example, my 4x800 team travelled 3200 meters at a speed of 10 minutes and 44 seconds.

My 4x8 team.

4. We can also measure how fast someone ran by using velocity. However, we could only use that measurement on the straight parts of the track because velocity requires a specific direction. If someone asked, "what was the velocity of that runner in 800?" you would say, "well, they rounded a curve which is not traveling in one direction so we can't measure their velocity". But if someone asked, "what was the velocity of that runner in the 100?" you would say, "well, they traveled in one direction so lets use the equation, v=d/t to find out".

5. We could also measure acceleration at a track meet. Acceleration is how fast an object picks up speed. We can measure this using the equation velocity/time.

Holt is accelerating by slowing down.

Rylynn is about to accelerate.

6. At the meet there was also long jump which is an example of projectile motion. The athlete jumps of the ground, sails up and then comes back down to the ground, trying to cover the longest distance. Lets say the jumper wants to cover 18 feet and jumps at a 45 degree angle. We can use the formula v=d/t to find the horizontal velocity. We can use the formula d=1/2gt^2 to find the vertical velocity. In order to find how fast the person was moving at any given time we use the pythagorean theorem.

Hank is in projectile motion.

7. In pole vault, once the athlete clears the bar, they fall down. This fall down is an example of free fall which is when an object falls due only to the acceleration of gravity. We can find out how far they fall/how high they jumped using the formula d=1/2gt^2. We can also find out how fast the person fell we can use the equation v=gt.

Elliott is about to free fall.

8. We can use Newtons Third Law and action and reaction pairs to understand how someone runs. Whatever force the person pushes back on the earth, the earth will push foreword that equal force. The person who pushes back harder on the earth will move faster.

Runners push ground, ground pushes runners.

9. Durring the track season I got a leg injury because I often ran on the hard track as opposed to the softer dirt trails. As we know from Newtons Third Law my foot goes from moving to not moving regardless of what surface my foot hits. Therefore my foot will have the same change in momentum regardless of the surface. Although my foot will have the same change in momentum, it will have a small amount of time to go from moving to not moving and therefore a large force on the track. On the trails, my foot will have a longer time to stop moving and therefore a small force so I will have less injury on the trails.










10. At the meet we ate sandwiches. The coaches used a credit card to buy those sandwiches. Credit cards work because of electromagnetic induction. In the credit card machine there is coils of wire. When the magnetic strip on the card goes through the colds, the magnetic field in the coil is changed. This induces a velocity which causes a current. This current sends a signal to the computer and allows the card to pay.

Go Blues!

Magnetism Unit Summary

Electromagnetic induction is when a change in the magnetic field of a wire loop induces voltage which causes current. This can be seen in traffic lights, airport metal detectors, credit card machines, and transformers. The magnetic field changes when a magnet moves through a coil of wire or vice versa.
In traffic lights for example, the metal of the car moves over coils of wire in the road which changes the wires magnetic field. This induces voltage which causes current. The current sends a signal to the light for it to turn green when there is a car there.
Transformers have no magnet but are made up of two current carrying wires next to each other. They are used to increase or decrease voltage and can be seen in most appliances such as refrigerators, hair dryers, computer chargers, washing machines, etc. The magnetic field of the primary wire changes because of its alternating current which causes a change in the magnetic field of the secondary which induces voltage which causes current.
Generators convert the mechanical energy of a spin into electric energy which is a change in current. Generators can be found in things like wind turbines or hydroelectric dams. In the case of the wind turbine, the wind spins the blades, the blades move the magnets through the wire or vice versa which changes the wires magnetic field which induces voltage which causes current.

Forces on Charged Particles are important when it comes to cosmic rays and motors. When cosmic rays, or charged particles approach the earth at its equator, the charges are moving perpendicularly to the earths magnetic field lines so they feel a force and do not enter. However if the particles approach the earth towards the geographic north, the charges are moving parallel with the earths magnetic field lines so they do not feel a force and they enter. This is what causes the northern lights and why the northern lights are only seen at the north and south of the earth. The geographic north and south are opposite from the magnetic north and south because of these magnetic field lines.
Motors are made of coils of wire and magnets and are the opposites of generators. They convert electrical energy from a battery or other power source to mechanical energy like the spinning of a wire. The current carrying wire feels a force in the magnetic field because of the magnet and this causes the torque of the wire.

Magnetic Fields are essential in understanding magnets and magnetism. The source of magnetism is moving charges. When charges move in a wire there is current. When something is magnetized, the domains of the object all line up with the magnetic field lines which go from south to north. Like poles repeal and opposites attract because the magnetic field lines need to be parallel in order for the poles to attract. An object can be magnetized if it is brought into contact with a magnetic field causing the domains to line up. Compasses are simply magnets that are free to move to line up with the earths magnetic field.