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!!

Motor Blog

In class today, we learned how to build motor. Motors are used in our every day lives and it is therefore important to understand what it is. A simple motor consist of a battery, copper wire and a magnet. In class today we were given a rubber band, two paper clips, a long strand of copper wire, a battery and a magnet. The goal of this lab was to make the copper wire spin. This is accomplished by constructing a motor. The two paper clips are placed at each side of the battery and suspend the loop of copper wire over the magnet. The paper clips create a circuit that is closed when the copper wire is added. The magnet is placed below the copper wire, on top of the battery. When building this motor it is important to suspend the copper wire just over the magnet, not touching. When a current is sent through the copper wire, the magnetic field produced by the magnet, causes a force on the moving electrons. This is similar to cosmic rays trying to enter the earths atmosphere. The cosmic rays bounce off the earths atmosphere because it is perpendicular to the earth magnetic field. The electrons in the copper wire and deflected by the magnetic field since they are perpendicular  If the copper wire was parallel, it would not feel a force from the magnet. The magnet causes the copper wire to spin as long as there is a current running through the wire. It is vital to scrap the ends o the copper wire in a specific way. We scrap the copper wire to allow electrons to flow and to make the copper wire spin in a certain way. only one side of the copper wire is scrapped. Imagine the wire suspended over the magnet by the paperclips. The current goes through one side of the copper wire and is forced by the magnet to spin. If electrons went through the entire copper wire, it would spin back and forth since it would experience two equal and opposite forces.

A motor works because the moving electrons in the copper wire, experience a force from the magnet's magnetic field. This occurs because the copper wire is perpendicular to the magnetic field. The paper clips are used to suspend the wire and to complete the current from the battery to the wire. The rubber band is used to hold these two paperclips in place. motors are used in our everyday lives. It is used in our cars, in fans, in lawnmowers, practically anything. You can attach a fan blade on the end of the wire and create a fan. Its that simple!!

Magnets & Magnetism

Everyone loves Bill Nye and his explanations. In this video we are introduced to magnetism. The video explains that opposite forces attract and like forces repel. The video also explains what would happen to a magnet if it was cut in half. This is a very important concept that is normally overlooked by many individuals. I also found this video helpful since it gave real life examples of magnets in our world. The video does not explain magnetic fields and what they look like which is a very important concept to understand when learning about magnetism. This video does however, explain what magnets are made out of and that our planet is a giant magnet due to the spinning core.

http://www.youtube.com/watch?v=ak8Bh9Zka50

Electricity Unit 6

In this unit my class learned all about electricity. Everyone knows what electricity is but I had no idea why lighting occurs, how a fuse box works and how to make a balloon stick to a wall b rubbing it against your hair. I was exposed to many different phenomenons that occur in a our day to day lives but never really know how they work.

During this unit I learned how a battery, wires, and a light bulb fit together to make a light bulb work. A light bulb has an inert gas inside the glass. Also inside the light bulb is a filament  This filament is usually tungsten and is the part the electricity flows through. In order to light up the bulb with a battery and wires it is important to realize that the circuit needs to be closed. If there is any open space in the circuit then the electricity will not be able to flow. This is why a light bulb doesn't light up if the filament is broken. This means that the circuit is incomplete and the electricity is unable to travel through the system. In a circuit, a light bulb is referred to as a resistor since it uses electricity. Any appliance that is drawing energy is referred to as a resistor. If you jumped off the ground when you touch an electric fence will you get shocked? The answer is no, but don't try it! The electric fence will not shock you because the circuit is not complete, in order for you to feel a shock  you must be touching the ground. The reason you shouldn't try it is because when you get on the ground again and don't let go in time you will feel a shock. If you place a large enough insulator, such as styrofoam under your feet, you will not feel a shock. This occurs because the electricity does not go through the styrofoam therefore the circuit is not complete.

After this introduction into electricity we began learning abut charges. A neutral charge means that there is no overall charge. If something is negatively charged then there are more electrons present. If something is positively charged then more protons are present. We already know that like charges repeal and opposite charges attract (electrons attract protons but repel other electrons). Charges ten to move through contact, friction (two objects rubbing), and induction (a charge is made without contact). An example of friction occurring in our every day lives is when we wear socks and rub the carpet. This friction creates a negative charge in your socks so when you touch someone else and complete a circuit the energy travels through them and they will experience a shock. Induction is a little more complicated. Picture two metal balls both neutral and both touching one another. If you put a negatively charged stick towards one metal ball, the electrons in the rod will repel the electrons in the metal ball. Once the two balls are separated  one will be positively charged and the other will be negativity charged. Lightning is also an example of induction but on a larger scale. The molecules in a storm cloud create a negative charge in the cloud. This charge attracts all the protons on the ground until a path is created between the ground and the lightning. Although the electrons in the cloud is traveling to the ground, the immense energy produces light which is what we see as lightning. Interestingly more, lighting actually goes from the ground up, it just moves too fast for us to notice!

We also learned about polarization during this unit. Conductors allows charges to move through an objects and insulators stop charges from moving. Such materials such as rubber and styrofoam are insulators and metals are normally conductors. An object becomes polar when the charges are separated  The object is still neutral however the charges are separate. Why does ceran-wrap cling on to a bowl? When ceran-wrap is removed from the box the wrap becomes negatively charged due to the friction. When the wrap is placed on the bowl it becomes polar. The negatively charged wrap is attracted to the strong bond between the protons in the bowl. This makes the wrap stick to the bowl. Now, Why does ceran-wrap stick to the bowl when the other charges are repelling the negatively charged wrap? Columbs law states the force between any two objects is inversely proportional to the distance squared.
                                                            Columbs Law: K(q1)(q2)/d^2
The wrap sticks to the bowl because the distance is small between the two negatively charged bowl and wrap making the force small.
To answer this question we have 4 step to follow:
1 step: Plastic wrap is charged by friction and when brought near the bowl, it becomes polarized.
2 step: The positive charges in the bowl move close to the negative plastic wrap and the negative charges in the bowl move away from the wrap.
3 step: The distance between the opposite attractive charges is smaller than the distance between the like repelling charges.
4 step: Since there is a greater distance between the repulsive forces  the force between them will be less than the closer attractive forces. Thus the wrap sticks to the bowl.

Why are electronic devices always put in metal containers?
Many people, such as myself  don't understand this question until it is explained. In order to understand and answer this question we need to know about electric fields. An electric field is an area around a charge that can influence another charge. If a positively charged circuit board is placed in a metal container, all the surrounding charges will become equal and opposite and will therefore not influence the hard drive. It doesn't matter where this positively charged circuit is placed in the container, all the surrounding charges will have no influence with the charge and therefore the hard drive is protected. This is known as electric shielding  Another example of electric shielding occurs when lighting strikes a car. The individuals in the car will be safe in the car.

Voltage is the potential difference between two points. We calculate voltage by dividing electric potential energy by the charge.
                                                                    V= PE/q

During this unit we also learned about Ohm's law. This law states that current is equal to voltage divided by resistance. Current is the ability for electricity to travel through a wire. This is measured in amps and the universal symbol is I. Voltage is the potential difference between two points. Voltage is measure in volts and the universal symbol is v. Resistance is the tendency for a circuit to resist an electrical current and is measured in ohms. We can increase the current through an object by either replacing the material, making the  path wider or longer. Why does a light get dimmer? It is important to remember when answering this question that resistance doesn't change. If we have a 60W light bulb  and it starts to get dimmer, the voltage is decreasing. Which light bulb offers more resistance, a 60W bulb or 120W? this question is a little tricky. The answer is the 60W bulb. The 60W bulb has a shorter, and thinner filament therefore increasing the resistance.

When talking about circuit there are two that we use. One circuit is called a series and another is called parallel. Think of a circuit as a roadway system. A series circuit means that there are multiple red lights on one road. These red lights cause the traffic flow to move slower. In a series circuit, the more appliances are added, the less current is available. This is due to the increase in resistance. In a series circuit if one appliance is removed, the circuit is open and therefore all the appliances turn off. A parallel circuit can closely resemble a rod with multiple routes. If one appliance is removed, the others continue to stay on. A parallel circuit also increases the current since there are more ways for the electricity to travel. Our homes are wired in a parallel circuit. If too many appliances are connected into a parallel circuit then he current becomes too high and can heat up the wire. This was one of the main causes for house fires in the past. We installed a fuse box which contains many circuit breakers. A circuit breaker will trip if too much current is present and will break the circuit. This turns off all the power in the house since a box is wired in a series circuit. We use a series circuit in fuse boxes to protect our homes from house fires!

Fuse Box Photo

      This photo is of a fuse box. A fuse box is put in every home as a safety precaution. A fuse box is wired in a series which means if one of the circuit breaker trips, all the power will be cut off. A circuit breaker trips when too much current is present. This high current is caused when many appliances are plugged into the wall. The more appliances are plugged in, the greater the current. This increase in current occurs since most homes are wired in a parallel circuit. A fuse box will immediately shut off all electricity in a house when it detects a high current. This protects our house from electrical fires.