Tuesday, May 18, 2010

Direct Current Circuits Relfection

We have just finished a unit on electricity and cirtuits. We learned about DC circuits, or direct current circuits. These circuits always have a battery, wires, and and a resistor (usually a lightbulb). They can also have a voltmeter, ammeter, different types of resistors, many batteries, and many other things to make the circuit interesting. In the diagrams below, I have examples of three types of direct current circuits: a series circuit, a parallel circuit, and a complex circuit (a combination of both).

This is an example of a series circuit.
This is an example of a parallel circuit.

This is an example of a complex circuit

Monday, May 3, 2010

Waves and Optics Reflection

I have learned a variety of things in our unit of waves and optics. I learned how to draw ray diagrams (with converging and diverging lenses and mirrors), how to solve problems involving waves, light, sound, lenses, and mirrors, and about light and the human eye. I learned the different types of waves, longitudinal and transverse, and a new letter called lambda. This means wavelength. I learned how to find lengths and speeds of waves along with many other variables. I also learned about the doppler effect and how it pertains to waves and sound. Lastly, I learned about mirrors and lenses. These were fun but a bit difficult for me.
Mirrors and lenses gave me a bit of trouble. I did not catch on to the ray diagrams very quickly, and in turn didn't fully understand many of the problems. I also had trouble with the differences in converging and diverging lenses and mirrors. The switching of signs for real, unreal, upright, virtual, converging, and diverging really threw me off for a little while. Eventually, with practice and a little help from my friends, I began to understand and kept working on it.
I believe that my problem solving skills are pretty good, and have improved tremendously throughout this year. I still struggle with diagrams, especially ray diagrams. I have improved with reading more into equations and finding more out, like if the focal length and radius are negative or positive based on the equation.  Physics has been a lot different than my other sciences, and involves a lot of problem solving and working things out. I think I still have some improving to do, but I have come a long way and will only get better.

Sunday, April 25, 2010

Forces at Work

This photo is a demonstration of several forces at work in day to day life. The birdhouse is suspended by a rope from a branch on a tree. The rope is the tension force which holds the birdhouse up. A tension force is the force that is usually associated with ropes, wires, and springs. It also counteracts the force of gravity. The acceleration of gravity is equal to 9.8 meters per second squared and always pulls an object towards other objects and always pulls everything down toward the earth. The tension force is opposite the gravity because it is pulling the birdhouse up, while the force of gravity is pulling it down. These two forces equal each other and cancel each other out, therefore the object is at rest and at equilibrium. If the birdhouse was not at equilibrium, it would either be falling or rising. This This birdhouse has many forces acting on it, and is an example of how physics is seen is our daily world. 

Tuesday, March 23, 2010

Einstein Quote!!

Albert Einstein said, “Its not that I’m so smart, it’s just that I stay with problems longer.” Albert was a genius, and pretty bright. He could work almost any problem, and was almost always right. He was very curious and inquisitive, and always liked to learn whenever he could. He never gave up learning, and never gave up on a problem if he didn’t know how to do it or if he couldn’t find the answer. This was his key to success, not just because he was brilliant, but because he worked so hard and never gave up. His curiosity and persistence made him who he is, and let him find so many answers and new possibilities. While others gave up, Einstein kept working and figured many things out. 

Wednesday, March 10, 2010

Ice Hockey and Physics!

Ice Hockey has a lot of physics involved! Hockey has lots of momentum involved. If you want to learn about hockey, ohysics, and the relation between them look at the glogster and GoAnimate!!

Click HERE to see glogster!

Click HERE to see GoAnimate!

Sunday, February 21, 2010

Energy Reflection

Part A:
This is what i have learned about energy and the conservation of energy. Energy is a conserved, substance- like quantity with the capability to produce change. Energy can be stored in numerous ways: elastic energy, kinetic energy, gravitational potential energy, chemical potential energy, and internal energy (usually friction). Kinetic energy is the energy an object has when it is moving, where gravitational potential energy is when an object is at a height. Energy can also be transformed into heat and sound. Although the energy may be transferred to another type of storage, it is always constant. Energy does not grow(gain more) or lose any of the amount, it just changes form. While learning about energy, we also learned about work. Work is the energy transferred by forces, causing a displacement. This work is just a change in the energy by a force, like a person pushing a box. The work is done by the person pushing.While learning about work we also learned about power. Power is the rate of work, always in watts. I have also learned about Energy Flow Diagrams. These diagrams show the energy and how it is stored at the beginning and the end. The system is also showed in the diagram. Energy Flow Diagrams are all qualitative, so after learning how to do those we learned many equations to solve the problems with quantitative answers.
I believe this unit is fairly difficult. I always confuse equations and forget which ones work best for certain problems. I sometimes have to try a few equations, but am usually able to solve the problem. The Energy Flow Diagrams are very helpful, and help me know which equation to use because I can see which energies I am looking for. When the energy changes form, it can be hard for me to see which form it ends up as. This is becoming easier for me as I do more problems.
I think my problem solving skills could be a little better, but have definitely improved. I am getting better at quickly finding the right equations after looking at the problem. When I see a difficult problem, I now see how I can solve it and try equations until I do. I believe with a little more practice, especially on power and work problems, my problem solving skills will be a lot better.
Part B:
Energy is everywhere in our world. When a car is going to when a car stops, there is a transfer of kinetic energy to internal energy (from friction). When a little boy is pushing a toy around on the floor, there is work (force). When a person jumps off of a cliff to go bungee jumping, the energy transfers from gravitational potential energy to kinetic energy. Energy is everywhere in our world, always there, just changing forms all the time.

Monday, February 1, 2010


How do snowboarders move so smoothly?
This is a glog that shows how forces and mtion cause snowboards and snowboarders to glide over the snow. It explains the friction and forces at work, and how they apply to the snowboarder. Snowbaords and the snow creatwe little friction, and this exlains how and why.
click here

Wednesday, January 27, 2010

Reflection: Gravitational forces, Centripetal forces, and Circular motion

I learned a lot about circular motion, gravitation, and centripetal force. I learned that uniform circular motion is when the object is moving at a constant speed in a circle. The velocity is found by 2pi(r)/T. T is the period, or the time it takes for the object to complete one full revolution around the perimeter of the circle it is going in. When an object changes direction, it accelerates. So although the object may have a constant speed, it does not have  constant velocity (scalar vs. vector!). The velocity is tangential, and the acceleration of the velocity is called centripetal acceleration. This is found by the equation v^2/r. The acceleration is perpendicular to the velocity. The force that keeps the object going in a circle is called centripetal force. This force is found by using mv^2/r. There are also vertical circles. These circles are not much different, accept for at the top you subtract mg and when it is at the bottom you add mg. Universal Gravitation states that the force that pulls all other bodies and causes them to fall exists also between all other bodies. This force pulls down, but also things together. This helps things like the planets stay in orbit.

What I have found difficult is knowing what equation to use at what time; especially with the gravitational equations. I also find the FBD's difficult to draw, because the forces can be switched around. I also sometimes get confused what the system is. I am still getting the hang of gravitational forces, but i think i am getting better. Practice makes perfect.

I think that my problem solving skills are pretty good, but could definitely improve. I think that with the more problems that I see, I improve with each one. I sort of freak out when I glance at a problem and it seems too difficult. But when I actually look at it and focus I usually see a way to find the answer. I think my problem solving skills are definitely improving.

Sunday, January 10, 2010

Newton's Second Law part A

I learned how to do many things after learning Newton's second law.  Newton's second law states, "for a particular force, the acceleration of an object is proportional to the net force and inversely proportional to the mass of the object." This law links mass, acceleration, and the forces. This can be used with many problems, and even systems. Systems don't usually balance out, and this law helps find the acceleration. This law uses the formula a=∑F/m or ∑F=ma. Using this formula I learned to solve problems with acceleration in them, not just problems at constant speed or at rest. I also found out how to solve systems, including problems using pulleys and Atwood's machines. With these problems I improved my ability to draw FBD's and calculate the sum of the forces. I have also learned how to calculate the friction force acting on an object. The equation for this is Ff= Fn(mu). mu is the coefficient of friction and is used to calculate the frictional force.

What I have found difficult with this law and these problems is when I do not have much information, and I  have to keep working on the problem and it somehow works out in the end. I get a little confused going through the problems without knowing multiple variables. Also, a am not quite a master at finding the mu and friction force, because we just learned about it and it is still fairly new.

I think my problem solving skills are improving and I am able to catch on to new ideas faster. Although I am not a master at the frictional force equation and problems yet, I am catching on to this idea much faster and already understand it with most problems. I sometimes find certain acceleration problems difficult when not much information is given. I am fairly secure with systems, and can usually find the answers that I am looking for. Overall I think I am getting better at solving problems and can grasp ideas quicker.