10: Tides
I had always wondered how the tides worked and why they changed the way they did, and now I know that it is because of the differences in gravitational forces caused by the moon and NOT the sun. Neap tides are when the moon and sun are at perpendicular sides of the earth, and these make for less severe highs and lows, while a Spring tide occurs when the sun and moon are in a line, this makes for higher highs and lower lows.
9: Stoplights
Many times I had been sitting at a stoplight in my car wondering how a stoplight knows that a car is there. With knowledge of electromagnetism, I can now see how the everyday stoplights work, and understand how genius the design is. When a car moves over coils of wire that are embedded in the ground, then the car amplifies the magnetic field of the earth, therefore inducing a voltage and a current in the wires. This current is read by a computer which tells the stoplight that a car is waiting.
8: Trajectory/ Thrown Objects
This lesson applies heavily to my life as a football player and the trajectory/ flight path of the football when thrown. Since all objects are acted upon by gravity, the flight path of a thrown object will be a parabola, the object will be at the same height twice in its flight path.
7: Momentum
This lesson was fun to learn because it let me know that mass isn't everything when it comes to momentum. For example a smaller football player can have more momentum than a larger player moving slower. Momentum = mass x velocity, therefore if a smaller object is moving really really fast then it will have a greater momentum than a slow moving large object.
6: Energy
The concept of transferring kinetic energy to potential energy was a fun one to learn. Kinetic Energy is the energy of motion, and can be found by KE= 1/2mv^2. Potential energy is equal to Mass x gravity x height or mgh. Energy can never be created or destroyed so one type of energy must transfer to the other. For example when an object is swung from a pendulum, it starts off not moving with only potential energy, but when it it starts moving some of its potential energy is transferred into kinetic energy.
5: Tangential vs Rotational motion
The difference between tangential and rotational motion can be seen in my life at track meets very frequently and is fun to think about. Tangential motion is the distance covered in a given amount of time by a rotating object, for example a gear might cover 12 prongs in 30 seconds. Rotational motion is the amount of rotations per given time, for example 3 rotations in 40 seconds.
4: Skydiving
Learning about skydiving was an interesting topic to learn and I had fun thinking about why air resistance works the way it does. When skydiving, your acceleration will only decrease from the point when you jump out of the plane or helicopter, but you keep speeding up until your air resistance equals your weight, this is called Terminal Velocity. Terminal Velocity is the fastest that an object can physically fall.
3: Rotational Inertia
Learning about rotational inertia was fun to learn about because you can see examples of it in life such as ice skating and rotating on a chair. Rotational Inertia is the tendency of an object to resist angular motion, the higher the rotational inertia, the harder it will be to start or stop rotating the object. Rotational inertia is based on an object's mass, and the distribution of said mass.
2: Conservation of Momentum
The conservation of momentum was fun to learn because I had always wondered why if you caught a ball on a frictionless surface then you would slide. Momentum will always be conserved in a system, and when you catch a ball, the momentum from the movement of the ball must be conserved and transferred into you.
1: Airbags
Learning how airbags keep us safe was really fun! Since Airbags increase the time over which your head or body is stopped, there will be less of a force on your body. This is because your body undergoes the same impulse to stop regardless of how you are stopped. Impulse = Force x time. Less force on your body means less chance for injury!
Wednesday, May 21, 2014
Tuesday, May 20, 2014
Windmill Blog Post
PVC pipe
1.) To know how a windmill design works, someone would need to know how Electromagnetic induction works. This is to say that when a magnetic field is changed near a wire then a current is induced in the wire, note that the magnetic field must be CHANGING. The coils of wire carry a current to whatever you may be powering, or to a generator. The magnets create a magnetic field that is moved near the wire to induce a current.
Plastic spoons
PVC Pipes
Coils of wire (copper preferably)
Magnets
Wooden Dowels
PVC Caps
Wooden Circles
Attach a pvc pipe to a pvc connector, drill hole in pvc cap. Connect pvc to more pvc and then to a base. Drill hole in center of wooden cirlce and insert wooden dowel. Glue plastic spoons in perpendicular directions every 90 degrees. Attach coils of wire to inside of pvc cap with ends of wire protruding from pvc pipe. Glue magnets in alternating North South pole arrangement on wooden dowel. inert wooden dowel into the pvc cap, and then it's ready to go! make sure the magnets are near the coils of wire so that maximum current can be achieved. When the fan blows on the spoons, the dowel will rotate as will the magnets which will change a magnetic field from North to South over the coil of wire which will induce a current.
3.) The factors that affect the induced current are the speed at which the magnetic fields are changed, the amount of wire that is present, and the proximity to the wire the magnets are. The 4 wire coil design worked very very well to produce lots of current. The closer to the wire that the magnets are, the more current that will be induced.
Video of our Windmill: http://www.facebook.com/l.php?
u=http%3A%2F%2Fyoutu.be%2FweLWy9qH7e4&h=tAQH0i_Lk
Friday, May 9, 2014
Magnetism Unit Review
Source of all Magnetism: Moving Charges
What is a Magnetic Field?
- Area of influence created by moving charges, particles have to be moving PERPENDICULAR to said field to feel a force
A magnetized object has Magnetic Poles, North and South
Domains are groups of electrons that spin in the same direction
an object can become a magnet itself if its domains become aligned, usually from another magnet.
When a fara-magnetic object comes into a magnetic field, it increases the strength of said magnetic field.
Electromagnetism is a word to describe a magnetic field caused by electricity
Motors are made of Coils of wire and Magnets. When a current is run through the coils of wire, the resulting force vector caused by the magnetic field produced by the magnet puts a torque on the coil of wire. Note that current has to be alternated for this to work. For example when we made motors.
Magnetic Induction:
When you start with electricity to produce a magnetic field, it is called Magnetic Induction. This is done by running a current through wires. When starting with a magnetic field to produce electricity it is called Electric Induction. Both are at play in Transformers. Transformers are two different coils of wire that aren't touching each other but are next to each other. When current is changed in one of them, a magnetic field is induced. This change in magnetic field causes a current to flow in the second coil of wire. Transformers can be used to step voltage up or down by changing the number of loops, otherwise known as turns, in the coil. Double the turns= double the voltage. Note that this only works with alternating current because it is a change in magnetic field that produces a current.
Generators have similar design to motors, only its role is reversed. A generator will store mechanical energy as electrical energy.
Credit Cards:
Credit cards have a magnetic strip that include specifically coded and uniquely magnetic sectors. The Card reader has Coils of wire within it. When the magnetic strip is run through the card reader, a specific amount of current is created by the magnetic field from the coded sectors. This current is then translated by a computer into the original code (numbers).
Primary Voltage/Number of turns = Secondary voltage/ number of turns
power is always conserved, power in = power out
Voltage x Current= Voltage x Current
VI in = VI out
For long distances it is better to have less current in a power line due to the excess loss of energy to heat from high current. This loss of energy means that the power companies are not getting as much profit. Note, however, that the Voltage increases while the Current decreases.
Paperclips- you can turn a paperclip into a magnet by putting it in a magnetic field to realign its domains to match the magnetic field. When the magnet is removed, the paper clip will produce its own magnetic field.
Magnetic objects stick together because when their poles are in the same direction, their force vectors and in the same direction. This means that they will add together and the net force will be attractive.
What is a Magnetic Field?
- Area of influence created by moving charges, particles have to be moving PERPENDICULAR to said field to feel a force
A magnetized object has Magnetic Poles, North and South
Domains are groups of electrons that spin in the same direction
an object can become a magnet itself if its domains become aligned, usually from another magnet.
When a fara-magnetic object comes into a magnetic field, it increases the strength of said magnetic field.
Electromagnetism is a word to describe a magnetic field caused by electricity
Motors are made of Coils of wire and Magnets. When a current is run through the coils of wire, the resulting force vector caused by the magnetic field produced by the magnet puts a torque on the coil of wire. Note that current has to be alternated for this to work. For example when we made motors.
Magnetic Induction:
When you start with electricity to produce a magnetic field, it is called Magnetic Induction. This is done by running a current through wires. When starting with a magnetic field to produce electricity it is called Electric Induction. Both are at play in Transformers. Transformers are two different coils of wire that aren't touching each other but are next to each other. When current is changed in one of them, a magnetic field is induced. This change in magnetic field causes a current to flow in the second coil of wire. Transformers can be used to step voltage up or down by changing the number of loops, otherwise known as turns, in the coil. Double the turns= double the voltage. Note that this only works with alternating current because it is a change in magnetic field that produces a current.
Generators have similar design to motors, only its role is reversed. A generator will store mechanical energy as electrical energy.
Credit Cards:
Credit cards have a magnetic strip that include specifically coded and uniquely magnetic sectors. The Card reader has Coils of wire within it. When the magnetic strip is run through the card reader, a specific amount of current is created by the magnetic field from the coded sectors. This current is then translated by a computer into the original code (numbers).
Primary Voltage/Number of turns = Secondary voltage/ number of turns
power is always conserved, power in = power out
Voltage x Current= Voltage x Current
VI in = VI out
For long distances it is better to have less current in a power line due to the excess loss of energy to heat from high current. This loss of energy means that the power companies are not getting as much profit. Note, however, that the Voltage increases while the Current decreases.
Paperclips- you can turn a paperclip into a magnet by putting it in a magnetic field to realign its domains to match the magnetic field. When the magnet is removed, the paper clip will produce its own magnetic field.
Magnetic objects stick together because when their poles are in the same direction, their force vectors and in the same direction. This means that they will add together and the net force will be attractive.
Thursday, May 1, 2014
Motor Blog
Function of Each part of the Motor:
Battery: provided a current through the system
Paper clips: acted as both a conductor for the current and held the motor loop up
Motor loop: main rotary piece of the motor, carried current and spun
Magnet: Creates magnetic field that puts torque on the motor loop
We scraped the armature by scraping one side completely off so that there was no insulator, and the other side so that there was half of the wire without insulator. We did this because when the motor loop would turn half way, it would want to reverse directions, therefore we had to have the current be cut off so that the motor loop could keep rotating.
The motor turns because a current is running through the motor loop. When this occurs, the magnetic field from both the moving charges and the magnet placed on the system create a force that puts a torque on the loop. This works until it half way rotates and wants to reverse directions per the magnet. This is why we stripped the armature to have the current turn off when the motor loop would want to reverse directions. The direction of force needed to be perpendicular to the plane of the motor loop so that it would create a torque.
This motor could be used for educational purposes, as it does not do enough work to actually be useful in anything else.
http://www.youtube.com/watch?v=YQCZ-60fxXQ&feature=youtu.be
Battery: provided a current through the system
Paper clips: acted as both a conductor for the current and held the motor loop up
Motor loop: main rotary piece of the motor, carried current and spun
Magnet: Creates magnetic field that puts torque on the motor loop
We scraped the armature by scraping one side completely off so that there was no insulator, and the other side so that there was half of the wire without insulator. We did this because when the motor loop would turn half way, it would want to reverse directions, therefore we had to have the current be cut off so that the motor loop could keep rotating.
The motor turns because a current is running through the motor loop. When this occurs, the magnetic field from both the moving charges and the magnet placed on the system create a force that puts a torque on the loop. This works until it half way rotates and wants to reverse directions per the magnet. This is why we stripped the armature to have the current turn off when the motor loop would want to reverse directions. The direction of force needed to be perpendicular to the plane of the motor loop so that it would create a torque.
This motor could be used for educational purposes, as it does not do enough work to actually be useful in anything else.
http://www.youtube.com/watch?v=YQCZ-60fxXQ&feature=youtu.be
Subscribe to:
Posts (Atom)