Generators

In this unit we constructed a wind turbine. You may have seen these generators placed on the countryside somewhere. They are generators and utilize mechanical energy in order to produce electrical energy. The wind pushes fan blades which turns either a loop of wire around magnets or magnets around a loop of wire. The wire feels a force from the magnets and creates an electrical charge. This is known as magnetic induction. In order to build a wind turbine it is important to understand different designs. There are three general designs for wind turbines that exists today. One design is know as Savonius VAWT. This is the design my group decided to use. This design caches the wind effectively and is able to spin freely.

For this project you will need:

Screw  1

Washer ($.18 x 2)

¼ x 2/2 wood ($.97 x 2)

dower ($.98 max price)

Smart water bottle ($1.50 x 2)

Grand total: $6.28

Expected Materials:

Hot glue (a lot)

Hot glue gun

Drill

Saw

Copper wire (a lot)

My group then went to Lowes in order to purchase the required materials. We purchased four washers, one wood round rod, two pieces of wood (¼ x 2/2 wood ($.97 x 2)) and two smart water bottles. The water bottles would be cut and used as the fan blades. We decided to use smart water bottles since the plastic is light and capable of holding a large force. These blades were glued onto the round wooden rod which was sharpened one side. The sharpened side of the rod would then be laced on the screw which was screwed into your base. When the sharpened stick was placed on the top of the screw it was able to move fast. The base would resemble a box. The top to the base would have a hole which would keep the wind turbine from falling down. This base allowed the wind turbine to stay in position and  move when the wind was added. 

Now the important part about making the turbine is coiling the copper wire correctly. For the copper wire my group decided to make 4 sections of 200 coils of wire. In order to coil the wire it is necessary to leave a small piece of wire free. This allows you to attach the coils to the voltmeter when testing the wind turbine. It is important that all the coils of wire are in the same direction. If the wires are not in the same direction than no electricity will be produced. Once one section of wire is coiled, leave a little space free and then coil the second wire 200 coil wraps. This is preformed 4 times. An easy method is to use a circular object to wrap the copper wire around. Once all the wire has been wrapped in the same direction cut the wire leaving a little space to attach the end into the volt meter. It is important to remove the plastic coating on each end of the wires. This need to be done or else the volt meter will not register any voltage. We placed the copper wire around the screw in order to be closer to the magnets. If the copper wire is close to the magnets than it will feel a greater force. This in turn will produces a greater voltage .

  

My group ended up having two series of fan blades. We attached three fan blades on the top half of our wooden rod and three smaller fan blades on the bottom of the rod. We also attached a small cardboard circle on the bottom of the wooden rod. This small cardboard circle contains the magnets. We used the washers as a means of attaching the magnets without using super glue. The magnets were placed on the washers which were glued onto the cardboard. When the fan blades caught the wind, the rod moved in a circle and thus moved the magnets around the coils of wire. These coils of wire generated electricity. Our design produced 0.121 volts. Not enough to power a small light bulb but still produced electricity. My advice to other attempting to create a wind turbine is to use a larger amount of copper wire and use more magnets. A different design can be used to catch the wind better It makes a large difference if the plastic coating on the copper wire is complete scrapped off.

Top 10 Places to Find Physics

There are many places where physics is found in our everyday lives. Many of these situations are unnoticed and therefore unappreciated. Physics surrounds our lives, if you like it or not its everywhere. In this post I will discuss the top 10 most frequent places where physics is present and you may not be aware of it!

10. Generator:
As you are reading this, you are using a computer. Your computer has a transformer in it which utilizes two different coils of wire. One coil of wire is used to either reduce or increase the voltage that enters into your computer. A generator is also used to power the computer. This generator (the power company) inputs mechanical energy in order to either a) turn a coil of wire around a magnet or b) turn a magnet around a coil of wire. This coil of wire feels a force from the magnet and thus generates electricity. This energy is then sold to you in order to power your electronic appliances such as the computer.

9. Motor:
Our automobiles, blenders.. anything that transforms electrical energy into mechanical energy is influenced by physics. A motor works when a current carrying wire feels a force from a magnet. The magnet thus causes the copper wire to torque and either spin he blades in a blender or the wheels in a car.

8. Tides:
You may not be aware of tides but if you live on the coast (such as myself) it influences your life. The tides are controlled by the position of the moon. The moon causes a gravitational force between the earth since it has a substantial mass and is located close to the earth. This gravitational force causes high tides and low ides in our world. These tides can produce a substantial amount of electricity when harnessed.

7. Balance:
Tight-rope walkers utilize balance in order to walk across the rope. We balance our selves when we carry a back pack or a handbag without even noticing it. Balance is when our center of gravity is underneath our base of support. When this is not present, the object will fall. A tight-rope walker will often carry a long pole across the rope in order to lower their center of gravity, closer to the rope.

6.  Air resistance:
Air resistance is all around us and is usually negligible when calculating physics equations. If you want to go sky diving, this is a very importance force to have acting against you. Air resistance will increase as your speed increases when you are falling through the air. Eventually, the force of air resistance will be equal and opposite to the force of gravity and therefore you will have a constant velocity. If air resistance was not equal and opposite, you would accelerate to the point in which stopping would be impossible.

5. Gravity:
Gravity is probably the most influential force that effects our every day lives. It affects our weight since it is the force in which the earth pulls us to the ground. If you went to the moon your weight would be significantly different however your mass would remain the same. Without gravity, we would not be able to walk and if we jumped, we would continue to increase height forever. A hover craft makes friction negligible and allows the craft to continue with a constant velocity indefinably.

4. G. Force:
Newtons first law states that an object in motion will stay in motion unless acted on by a non-zero net force. When a car accelerates, we sink back into the seat because our body wishes to stay at rest but is forced to move forward. When in an airplane, g-forces can be experienced. This occurs when acceleration is felt as weight. When an airplane pitches up, you will sink back into your seat and feel heavier and thus experience a g-force.

3. Airbags
Airbags are installed in every car as a safety precaution. They deploy during accidents in order to protect the inhabitants of the vehicle. When an airbag deploys we go from moving to not moving. The change in moment is the same whether we hit the dashboard or the airbag. If the change in momentum is the same, than Impulse is also the same. Whether you hi the airbag or the dashboard since impulse is the same, airbags will increase the time and the force therefore decreases. This decrease n force protects us from a large blow.

2. Stop Lights:
Stop lights are everywhere and not many people really understand how they operate  A stop light receives a signal when a car moves over wires embedded in the ground. Since the car has magnets, the wire feels a force from the magnet and produces electricity. This signal is then sent and translated to the presence of a vehicle. Now you know why stop lights change from red to green!

1.  How does a horse pull a buggy or How do we move forward:
This is a difficult concept to understand but it occurs every day. A horse pulls a buggy because the horse exerts a force equal and opposite to the force that the buggy exerts. This is because newtons third la states that every action has an equal and opposite reaction. The buggy moves forward because the horse exerts a greater force on the ground than that of the buggy.

Unit 7 Blog Reflection

For this unit, my physics class discussed magnets and electromagnetic induction. We will be discussing magnetism (magnetic poles; electromagnets), forces on charged particles in an electric field (motors), electromagnetic induction, generators, and transformers.

Guiding Question- Why does a paperclip stick to a magnet?

Magnetism is surrounded by the common knowledge that all charges are magnetic and moving charges causes magnetism. Each electron is spinning in a domain. A domain is a cluster of electrons spinning in a random direction. When an object is magnetized all the domains line up in the same direction . All of the electrons run towards the north pole and run away from the south pole. These electrons eventually go through the north pole and come back around to the south pole. The movement of electrons are represented as lines and referred to as field line. The north pole of a magnet sticks to the south pol of another magnet because the field lines math up. The north pole of a magnet repels the north pole of another magnet because the field lines are opposite. If a magnet is cut in half, you you have a north side and a south side? The answer is no! You will just have two magnets now! Talk about saving you money. When referring to the paper clip question, it is important to realize that the paperclip has no set poles. The domains in the paperclip are random. A domain is a cluster of electrons that are spinning in the same direction. The magnet has a magnetic field. when the magnet is close to the paperclip the domains of the paperclip align to match the magnetic filed of the magnet. The paperclip now has a north and south pole. The north pole of the paperclip is attracted to the south pole of the magnet and thus the clip will stick to the magnet! We also discussed the northern lights and why they occur. The northern lights are caused by comic rays entering our atmosphere. Why do we only see these rays at the poles? The rays are noticed at the poles because when the magnetic field is parallel to a charged particle, the charged particle will not feel a force. When a particle is perpendicular to the magnetic field, it will feel a force and therefore bounce off. The rays feel a fore at the equator since the charged particle is parallel to the magnetic field of the earth. The northern lights enter at the poles because they are parallel to the magnetic field. This causes an increase in cancer at the poles since these rays contain cosmic radiation.

Guiding Question #2:  What is needed to construct a motor?

Know we know that a charged particle feels a force form a magnetic field when it is perpendicular. This causes the particle to 'bounce off' and feel a force. We can apply this idea to a motor. A motor is used to transfer electrical energy, into mechanical energy. A motor is constructed from a battery, a rubber band, two paperclips, a coil of copper wire, and a magnet. The copper wire is made into a loop with two strands sticking out from either side. The copper wire is mounted over the magnet which is placed on the battery. The paper clips position the copper wire over the magnet and complete the circuit. The rubber band is used to hold the motor together. The main idea behind a motor is that a current carrying wire feels a force from the magnet. the magnet exerts a force on the copper wire since they are perpendicular. This causes the copper wire to torque. We could attach fan blades to make a fan or even wheels to make a car. The spinning wire, produces mechanical energy, capable of moving and object.

Guiding Question #3: How does a credit card work?

A credit card, traffic light, metal detector all work utilizing the ideology of electromagnetic induction. The basic idea surrounding this is a loop of wire in a complete circuit with no current has a magnet moved through or over the wire. This magnetic filed charges the wire and endues a current. The current can be used for a variety of things, If the magnet is constantly moved, changing the charge, a generator is created. A credit card contain a series of magnets in the black strip. There is a coil of wire in the credit card machine. As the credit card is moved through the machine, the magnets change the magnetic field within the loop of wire. This change in magnetic field endues a charge which is translated by the machine. The machine translates this signal into you credit card number. This answer an be adapted to answer how a traffic light detects a car, or how a metal detector detects metal. Pretty cool but we are not done yet!!

Guiding Question #4: What is the difference between a motor and a generator?

A generator has the same concept as the credit card machine in the previous question. A generator produces electricity by putting mechanical energy in. This is entirely different from a motor which transfers electrical energy into mechanical energy. The generator has a coil of wire and a magnet  The magnet is either moved around the coil of wire or the coil of wire is moved around the magnet. A generator requires an ac current. The current need to be alternating or else the coil of wire will not feel a force. generators are used to power our homes during a power out. Normally the mechanical energy is either steam or wind, but can also be physical turning or fuel could be used.

Guiding Question #5: What is so special about transformers?

A transformer is used either increase the amount of voltage or decrease the amount of voltage in an appliance, Your computer has a small black or white box attached to the power cable. This transformer is used to convert the 120V in the wall into 300V in the appliance (these are made-up numbers). This increase in voltage is referred to as a step-up and commonly occurs for big appliances such as the washing machine or a microwave. A step-down transfer occurs when the energy is produced from the power company and transferred to your house. The power company makes the current very low and the voltage very high. This is done to reduce unnecessary power loss. if the current is very high, the power lines will heat up. Once the energy has reached your house it under goes a step-down. This occurs because in the transformer are two sets of wires. If we step down then the primary coils inside the transformer are larger than the secondary. If you want less voltage, then there will be less coils. We can calculate the number of coils in the primary or secondary or calculate the voltage in the primary or secondary. We use the formula;
                   Primary # of Coils/ Primary Voltage = Secondary # of Coils/ Secondary Voltage

For this unit, I found the motor section difficult to understand. During class we were explained that 'a current carrying wire feels a force from the magnet which causes it to torque.' I was always confused on what the force was that produced this torque but never fully understood. This topic, although appears difficult, needs to be taught in a specific order. I really enjoyed building the motor since it allowed me to have a visual and better understand the importance of every part. I hope that you build a motor!!