Day 15: Power and Potential

  First, we did a very interesting experiment. We have 2 batteries, 2 bulbs and 3 wires. We need to found a way can make the bulbs get brighter and dimmer.

  These are the graph we drew about how we did to make bulbs brighter and dimmer. We put the 2 bulbs parallel if we want brighter. We put the 2 batteries parallel if we want dimmer.

  Professor used ohmmeter to found the resistors of the heater.

  These are the three things we need to know in order to find delta T.

  These are the temperature vs. time graph by using Logger Pro. First graph is regular and second one is twice volt than first graph. We can see that the increase of temperature is by factor of 4.

  We found out the equation for temperature. If we make to 2V, the change of temperature should be 2 times. But actually is more than 2 times.

  We found the resistor did not change, so when the V=2V and I=2I, the change of temperature should be 4.

  we found the resistant on human body by using I=V/R.

  In this picture, we found the paths did not affect the work, but direction of gravity will.

  There are three arrows, we need to find the work on each arrow. And we found Wa>Wc>Wb.

  This is a particle and its electric field.

  We found the change of voltage is kQ/r.

  We started to do a vpython lab. Then we drew the graph and find the V of different particles.

  There are the different between plagarism and collaboration.

Conclusion:
  At the beginning of the class, we did a interesting experiment and we found the bulbs will brighter if we put bulbs parallel and the bulbs will dimmer if we put batteries parallel. Then we did another experiment by using Logger Pro, and we found the factor of the temperature change is 4 if we double V.Last, we did a program by using Vpython and talked about our Vpython homework.

Day 14: Current Voltage and Resistance

  We have a wire, bulb and battery. We need to make the bulb light.

  There are three arrangements that the bulb will light and not light.

 
  There are the explainations that why these two arrangement can not light.

  Now we have two batteries so we can make the bulb brighter.

  Professor use a rubber bar rubbing it to animal skin and put the bar on the ball. Then the two pieces of sheetmetal separate.

  We predict nothing will happen when battery on the ball.

  Bulb can light because there is a circle between the battery and the bulb and the charges can equilibrium.

  There are two things relate to waterfall.

  There is an exercise we did to found power by using V and I.

  We used the equipment to measure the current and we got 124 mA. If we reverse, we found it goes opposite direction.

  We predict the model c is correct, but experiment showed the direction of the current will be same in both wires.

  We found out the things that will influence current.

  There are the relationship between current and voltage by using Ohm's law.

  There are the current and voltage graphs we found by using Logger Pro.

  There are two graphs: V vs. C and C vs. V.

  We found the unit for resistance.

  We used the equipment in the first picture and found the longer length has larger resisitivity.

  In this picture, we found the larger diameter or area will get smaller resistivity.

Conclusion:
  At beginning of the class, we did a very interesting experiment to made a bulb light by using battery and wire. And we found different arrangements will make bulb light or not.Then we found the relationship between current, voltage and resistance by Joules Law. Then we started to learn Ohm's Law, we found the proportionality of current and voltage are related to resistors. Last, we found the unit for resistance, a very interesting Greek letter.

Day 11: Gauss' Law

  First, we use arbitrary surface and the line of flux in and out of the surface to find the charge enclosed of three circles.

  Q is proportional to flux. Then we found the unit for k is c^2/(Nm^2).

  After, we found the relationship between q/e_{o and E*A.}

  The black net in the picture is called Faraday cage. We need to predict what will happen to the foils after the cylinder charged. 

  Our predict is correct, only the outer foils will move away from the cylinder.

  Q is on the surface when cylinder is charged.

  The relationship between σ and E0.

  When radius is double, how perimeter, area and volume will change.

  This picture shows the Gauss' law.

  This picture shows the relationship between E, q, and r after we plugged in 4pi*r^2 as area.

  We used Gauss' law to find spherically symmetric charge distributions and the electric field. 

  In this experiment, professor put a ball into the microwave and we saw it fires. Then professor put a CD into the microwave, it broke and bubble fires inside.

  We found the volume by using pi, r and L, charge with a radius of r/2 and total charge Q. Also, we found the surface area of the cylinder.

  In the last two picture, we found the electric field on the circle.

Conclusion:
  Today, we did a lot interesting experiments.We analyze the Gauss' law and showed how it works in real life.After, we figure out the relationship between electric field give the charges of Gauss'law with different materials. Also, we put different things and materials into the microwave and see what will happen. Last, we did some interesting exercises relate to electric field.