Wednesday, May 19, 2010

Don't Let it Catch on Fire!

      On my first try on the simulation, my battery and switch caught on fire.  This is because the negative part of my light bulbs were not connected to any part of the wires.  A DC circuit must be connected by wires to the positive and negative sides of the battery. 

      The picture on the right resembles a typical series circuit.  It involves three light bulbs, a battery, and a switch.  In a series circuit, the current is the same throughout the wires.  All of the light bulbs in a series circuit have the same amount of voltage.  If one light bulb is unscrewed, they all turn off.

The picture on the right resembles the typical parallel circuit.  There are three parallel wires, each with a light bulb, and a battery.  The current through each wire is the same.  The voltage through each wire depends on the resistance of the light bulb.  If one light bulb were unscrewed, the others would still be on.

The picture on the right resembles a typical complex circuit.  It involves a parallel circuit and a series circuit.  The resistance is the equivalent resistance of the parallel circuit plus the resistance of the lone light bulb in the series.  The voltage of the series circuit bulb is greater than a light bulb in the parallel circuit.

Sunday, April 25, 2010

In this picture, I placed a pole into the water.  The pole looks like it is at first straight, then bends just as it hits the water.  In reality, the pole is completely straight.  The water seems to bend the pole becuase of the physics property of refraction.  Refraction is the bending of a ray as it passes from one medium into another.  In this photo, the two mediums are air and water.  In the air, the speed of light travels at a higher speed than the speed of light in a material such as water.  In water, light will generally travel about three-fourths of its velocity in the air.  Therefore, the incident angle created by the straight side of the pole will be different than the refracted angle created by the bended part of the pole.  I measured the angle of incidence at 42 degrees and with the equation from Snell's Law, the refracted angle in the water is 30.2 degrees. 

Tuesday, March 23, 2010

Einstein quote explained

"Only a life lived for others is a life worth while"
I believe this quote means that when you are living a life for yourselves and buying unnecessary things for yourself, it is not a so luxurious life than that person would think.  Living a life for others, however, is the best life you can give because you are giving life to others.  Einstein thinks that a vain life is an unnecessary one but a life of truth and honesty is the best life you can live 

Thursday, March 11, 2010

The relation of physics to Ice Hockey!

Ice Hockey is a sport in which two teams try to score the most points.  The NHL, National Hockey League, is where the best players are.  Below are two digital tools which explain more about ice hockey.

Click HERE to see our glogster

Here is a goanimate about the relation of physics and ice hockey physics project by jonnyboy721

Like it? Create your own at It's free and fun!

Tuesday, February 23, 2010

This is what I learned about energy.  I learned that energy is a conserved substance-like quality with the capability to produce change.  I also learned that energy cannot be destroyed, it can only be transferred from object to object.  Energy can be displayed using an energy flow diagrams and bar graphs.  I have also learned that work is a measure of the amount of change that a force produces when it acts on a body.  The equation for force is W=Fx or if there is an angle, W-Fx cos theta.  The unit of work is a joule.  Power is the rate at which work is done by a force.  The equation for power equals P=Fv.  There are four types of energy.  The first type is kinetic energy which is the energy a body has by virtue of its motion.  The equation is KE=1/2mv^2.  The second type of energy is Potential energy, which is the gravitational potential energy of a body.  The equation for it is PE=mgh.  The third type of energy is elastic potential energy, which is associated with elastic materials.  The equation is PEe=1/2kx^2.  The last type of energy is mechanical energy, which is the sum of kinetic energy and all forms of potential energy.  Its equation is ME=PE+KE.

What I have found difficult about what I have studied is the energy flow diagrams.  At first I did not understand how they are qualitative, not quantitative, but now, I understand the energy flow diagrams.  Another confusing thing about this subject is the concepts of energy.  I really did not understand how energy could be transferred at first, but now all of the concepts come easily to me.

My problem-solving skills are fine for this subject.  At first, I did not understand how to solve the equations with power, but then realized Fg was the force they were looking for.  Also, the problems with elastic energy were difficult at first.  I now realize how to do the problems

Can you make any connection(s) between what we studied and everyday life, history, situations in the world, any other subject you are studying or your own experiences? 

Yes. If you move, hit, or push anything, there is a transfer of energy happening.  When playing basketball, when the ball hits the floor, the floor will hit the ball back up to you.  Also, in football, when a head on collision happens, the player who delivers the most power will knock the other one down on the field 

Monday, February 1, 2010

My project is about Newton's Third Law and the action-reaction pairs that apply to baseball.  I have a glog that will go into depth about my idea and i have a video from GoAnimate which is for your viewing pleasure. Physics of Baseball by jonnyboy721

Like it? Create your own at It's free and fun!

Tuesday, January 26, 2010

Circular Motion and Gravitation

This is what I learned about Circular Motion and Gravitation. I learned that when moving in a circle, an object travels at a distance around the perimeter of the circle so that when the car moves at 5 m/s, the car would travel 5 meters along the perimeter in one second. This is the period T to get one complete rotation and it is given in seconds. The frequency is the number of rotations per second. In the case of circular motion when an object is accelerating, the acceleration is centripetal, meaning towards the center of the circle. I have also learned about Newton's Law of Universal Gravitation, which states every object is attracted to every other object in the universe.

What I have found difficult about what I have studied is figuring out what the centripetal force is. At first, I had no idea how to find it but now I realize the Centripetal force is the force pointing towards the center of the circle in the FBD. The Centripetal force is provided by the force which keeps the object in circular motion.  I have also found it difficult when the coefficient of friction is added to the problems. I did not know where the equation of mu times mg was from but then I learned where it was made from and how to convert it into my problems.

My problem solving skills are growing. With each mistake, I see how to apply every equation to solve any problem. I am doing well with the FBD's and knowing what provides the centripetal force. An area of concern is I am not sure what exactly the force to maintain the car's circular motion is. But for now, my problem solving skills are fine.