3/26 Flux

We are given a scenario where an electron goes through two plates with opposite charges. We draw the trajectory of the electron and determine that it is the same as projectile motion. To the right is how two opposite charges behave when they are not colinear.

In the case that the charges are not colinear, there is torque. We derived a formula for torque and then derived the work done from the derived torque formula.

This is our prediction for how the VPython code would look in red, and how the vectors should look in green. 

We drew the flow of an electric flow given that it was between two opposite charges and two negative charges.

We calculated the formula for flux in red and we found the normal vector for the 3D objects.

We were asked to calculate the flux on the box. In order to illustrate this, we opened up the box to clearly show which sides of the box had 0 flux because it was parallel to the electric field and which sides were not parallel. The sides marked in green individually had flux but canceled each other out since one side had flux going in and the other side had flux going out.

3/24 Electric Fields

We use Python to program a 3D graph where we can visually see the direction the electric field is going from the point charge.

This is a prediction of how we expect the VPython code to look up when it runs. Our prediction was wrong. 

This is the calculations to find the X and Y component of an electric field.

We use Microsoft Excel to calculate the electric fields given the k, q, and  the radius.

We used line integrals to calculate electric field across a line.

This is a list of descriptions of electric fields.

This picture shows the steps needed to be taken in VPython to make a graph that looks like the one we drew on the whiteboard.

We use Microsoft Excel to calculate the electric field in the X and Y axes. Since the point charge was at the center, the sum of the magnitude is 0.

Python 3D Modeling Program

This is challenge 1. This challenge was very interactive. I had to plan out the steps before I translated them into code.

This is challenge 2. This one wasn't as hard as the first challenge because everything was basically setup in the video. The balls were also lined up so that you could tell the distance between them was exactly 1 and the 2 rightmost balls were on the same x coodinate.

3/19 Coulomb's Law and Electric Charge

We are asked to predict the behavior of a statically charged balloon on a glass window. The balloon was charged using hair then silk to see if there would be any changes. The balloon stuck to the glass both times. Then we wrote out a way to explain to a child what charge is. 

We are introduced to Coulomb's Law and used the formula to find the electric force between two charges.

Add caption

The above two pictures are from our lab where we conducted an experiment using Logger Pro 

This is when the machine is turned on. The electric charge wants to escape to its surroundings thus making the paper stick out like spikes.

This picture shows the device turned on but with the paper dangling. This is because the metal on the propellor is a better conductor than paper which allows charge to escape through it better than paper. This caused the propellor to spin clockwise.

We conducted an experiment using a machine that could generate an electric charge to see if a propellor would spin or bounce off the machine.

We used Coulomb's Law and the gravitational force equations to derive the ratio between the Force of Gravity and Coulomb's Force.

This is the relationship an electric force, F, and the distance, D, the forces are separated by. 

This is the graph from our experiment where we used a premade video of two metal balls repelling each other. The graph on the right is the positions of both the balls between 0-10 seconds. The graph on the left shows the Force of the two balls acting on each other versus the distance they are apart from each other. It showed that our predictions on the relationship between Force and Distance are correct.

We used our knowledge of mechanics from a previous physics class to derive an equation that would solve for the force of the swinging ball.

We used two pieces of tape to show that oppositely charged objects will attract each other. We used the table to reverse the charge on one piece of tape.

These are the follow up questions that were asked after we conducted the tape experiment. We did an experiment using tape that were oppositely charged and an experiment where the tapes were the same charge. From these experiments we concluded that there is more than one charge and that the force is greater, repel or attract, the closer the tapes.

3/17 Entropy

Purple Peeper Beaker (Purple People Eater) Not related to science at all.

Stirling Engine still running even after being removed from the hot and cold reservoirs.

The Stirling Engine operates by putting a two reservoirs of different temperature (the bigger the temperature difference the faster the engine) below and above the engine to make it run. Depending on which is cold and which is hot, the windmill will rotate differently.

This is Stirling Engine when there is a hot reservoir below the engine and a cold reservoir above the engine. The windmill is spinning clockwise.

The cold and hot reservoir are swapped making the Stirling Engine rotate counter clockwise.

We drew graphs of how different processes behave in a temperature vs. entropy graph. We also calculated the efficiency of the Stirling Engine we experimented with in class. The temperatures used were the temperature of the cold and hot reservoirs.

We are introduced to COP(Coefficient of Proficiency) and are asked to calculate the heat energy given the information marked in red. It turns out that we did not need the molar mass, or volume since we can calculate Qh by Work*COP.

We are introduced to Epsilon and are asked to calculate it given the formula for it and the values marked in green. 

We calculated for the final temperature when entropy is equal to zero.

We derived an equation that can be used when entropy is equal to zero.

We found the Coefficient of Proficiency by finding the efficiency of the system and multiplying that by the max COP. Part b shows that we calculated for Qh with the information found in part a.

We calculated the amount of time it would take to phase change water into ice if all the energy inside the fridge was directly affecting the water. We found this number to be practically impossible.

 Professor Mason uses bubbles to show that bubbles that are denser than the air would fall to the ground. 

In this picture, Mason creates a bubble formed from methane gas to show that it floats and that if it were lit on fire, the bubble would instantly vaporize.

3/12 Carnot Engine and Otto Engine

This is an example of a thermal engine where one cup contains ice cold water and the other cup contains hot water. The hot water naturally wants to transfer its energy to the cold water and the engine in the middle spins based  off of this energy transfer.

This is the thermal engine in spinning in the direction of the heat transfer. Since the heat goes from the right cup to the left, the spinner spins counter clockwise.

This is where the cups are switched and the spinner spins in the clockwise direction.

With the cups removed, the engine is attached to a power supply and takes away heat from one metal leg and transfers it to the other. The student is touching both sides to confirm the the temperature.

This is our predictions for how the thermal engine would behave in both the experiment with the cups and with the power supply.

We calculate for the Cv and its relationship with R using the first law of thermodynamics.

We calculate for how moles and change in temperature relate to Cp, Cv, Pressure, and volume. We take the derivative of P delta V and use product rule which is why our numerator is not P delta V.

We derive a relationship between change in volume and change in pressure to set up a differential equation relating the two rates. We take the definite integral of pressure and volume and use algebra to cancel our variables and ended up with (ΔP/P) + (ΔV/V)(Cp/Cv)=0

Given that , we were asked to prove that  where gamma = 5/3. After we proved it, we found how those equations can be used to calculate work.

We are given an adiabatic problem where we use our derived work formula and plug in numbers to find the work done by the change in volume of the system.

Using the equations we derived in class, we were given a scenario where we have a Carnot engine where adiabatic and isothermal reactions occurred in one cycle. Between each of the 4 points, we had to calculate the Work, Internal Energy, and the Heat transferred and the efficiency of the engine.

This is a model of how the Otto engine operates.

This is the combustion part of the cycle as represented by the red glowing light. 

We answered the question of how to increase efficiency by answering that we could increase the difference of the cold and hot reservoirs by adding more radiators for more cooling. We answered the question of how to physically altar an engine to  increase work done by an engine. We were asked to draw the 2 additional degrees of freedom gained when a diatomic molecule is split into two.

Summary: We learned how different types of engines operate to create work from heat transfer. We learned equations that included Constant Volume(Cv) and Constant Pressure(Cp) and derived their relationship with the ideal gas law constant, R, and how it is conserved in a thermal reaction. We discussed different types of engines such as the uranium thermal engine used in rovers exploring space and the engines of old "Otto"mobiles.