Day 9 Lab 03/24/14

Electric Flux

After the introduction of electric fields in different situations but mostly were the fields are constant. The purpose of the experiment was to find why we use the equation we do to find the flux of an equation. We also saw how the electric fields interact with either by themselves or with another charge, showing that they repel or attract. When two charges are enclosed in a surface with like charges reveals that the net charge is zero and the flux is also zero. In order to see these affects of the charges the labs were doing activities on websites like Active Physics that put different charges inside a surface or moved out of it and see how to flux is affected. Another part of the experiment was to see the angle, electrostatic force, and the area also can find the flux and finding  the relationship with a graph by finding angles and the surface area.


The following images are the activity done on an application by Caltech to view the interactions of charges:

This the image of one charge in an electric field having the number of lines changing with amount of charge is being added to the field. In this case the electric field lines show ten lines coming from a positive 2 charge and changing as we reduce or increased the charge number. 

The interaction of the field when two opposite charges are placed next to each other showing how th middle lines between start to curve up and dense up. They add lines because one charge has 5 lines so when put to a negative one's lines they created ten lines.

This is the answers of the lab manual pertaining to the electric fields and came to the conclusion of the lines signify the magnitude of the attraction between two charges. And the direction of the lines represent the direction of the electric fields.  

The second part of the experiment was using an area to now introduce the flux with electric fields and angles by trying to find the certain angle to cover a specific area. And came to the conclusion the angle increases every time to find a lesser amount of area which was the number of nails.

This is the lab equipment used to find the relationship between the angle of the wire and the number of the nails in the wire which was the flux. In the end we want to find a relationship between the two to find an equation E*A*cos theta. 

After the input of the data points pertaining to the number of nails(flux) and the angle to come out with a graph that looks like a cosine graph. When it came to find the negative number of nails it is the same angle as the positive one.

The next part of the experiment was using active physics to see the interactions the electric force, the charge and the area being enclosed.

 This is a positive charge in the oval showing that there is flux but there is no force in the system of the activity. It also shows the electric field pointing away from the charge and circle.

However when two opposite charges are placed inside the enclosed area they end up canceling each other out resulting in the net charge indie being zero. With the flux is also being zero because they cancel each other inside the surface and the electric force is also zero.

This is the calculations and conclusions the group came up with following the experiment to find the q enclosed. One conclusion we stated to be important was that the flux is directly proportional to the net charge inside the area. And the equation of the due this experiment  is qenclosed/epsilon0=integral of EdA.

Day 8 Lab 03/19/14

Electric Fields

After doing electrostatic forces and understanding of the distance relates to the charges that are located in the different situations. We also learned how these field vectors run with the surfaces of objects and how they interact. In order to understand the way electric field works, the experiments of Active physics will explain the different scenarios the field affect the charge and the forces of electricity. Also being able to know the way to apply qualitative numbers in problems where the charges are different places and use those numbers to come close to the actual numbers.

This is the first simulation of the activity where the charge is dragged to another charged particle and in a image below show our board of answers explaining what is going but a little explanation is that like charges repel from each other.

The charge in the middle is a negative charge and the fields are shown around the charge in uniform circles as seen by the image and the arrows are point toward the charge. With the variables given in the simulation and the lab notebook we were able to find the Q of the charge which was 3.6*10^-7N/C. 

This is the same activity as the one prior but this one has a positive charge in the middle which still show a uniform field around it. Also the charges this time the arrows are pointed away from each other.  

 The third demo of the activity  is a charges passed within two plates of charge and we saw tat when negative the electric field radiates inward and it opposite direction when it is positive. 

 This is the calculations and explanations of the activities from active physics relating to the electric and charges. It explained the different types of the situations the charges can be applied.

This a problem in the lan manual which the charges were placed in different locations of the graph within the negative and positive side of the graph. This is were we used qualitative values to find the electric forces applied and come close to the actual numbers.

With the qualitative values obtained in the problem before, one of the ways to use them to find the forces was to apply it to a spreadsheet and let it do the calculations. 



This is level one of the electric field hockey in which you can see the affect one article like a proton can guide an electron to a specific field by placing them to locations. The interactions between the charges casues the electron to be repelled from the proton and make its way to the goal.

The second level of the field hockey using the same way of the charge interactions between the particles and guide itself through the field.

Day 7 Lab 03/17/14

Electrostatic Forces

In this lab we began to introduce the new force of electricity between the different types of charges in the object as well. The experiments that were done because these were showing how the matter of charges interact in charge and distances and the amount of force is applied in different situations. The first experiment was the one with using strips of tape and applying charge to them and bringing  them together to allow the group's to see how they interact and prove the hypothesis at the beginning. The second was a video of analysis of a hanging ball charged and another being brought closer to find the change the relationship along with the change in the angle. The equation that came out of these experiments was Coulomb's Law F=kq0q1/r^2.

This is the equipment of the experiment that was used to see the interaction of the strips once they received a charge by ripping from each other. The group saw that each strip had their own charge because each strip interacted differently with one attracting or repelling each other.

 These are the answers to the results we observed by the strips of tape experiment were in the first part we saw that they attracted to each other when brought closer increasing the attraction. In the end we had to make an experiment proving the hypothesis in the beginning of the manual after the strip experiment proved the first hypothesis.

Before the second the experiment can begin we had to find how the angle change can affect when a particle has a charge and makes an angle. We had to find the relationship between the angle and distance from the first part to the final part. After going through the experiment we came to an equation of inversecos(L/h-1).

 This is the picture of the calculations in which we tried to find the relationship or equation in this situation where the angle changes. However, we wanted in different terms than the one in the image for example in terms of variables m,L,g and theta. 

 This is what we wanted in terms of the variables from the image above by applying to a problem and using a force diagram to show how the angle change plays a factor in the calculations. In the end of the calculations we came to an equation to relate to the angle change problem which came to be F= mgtan(theta). 

 After practicing and seeing the scenario with a hanging mass changing the angle we started the video analysis which had the same situation but in this case it was due to charges pushing the ball changing the distance. We were able to see the similarity between the gravitational force equation after the analysis causing it to see it as a new force but instead of gravity being the force we now had the force of electrostatic. With images shown below you are able to see the process of the experiment to see how we came to the conclusion of the charges interact with each other using Coulomb's Law and how similar it is to the gravitational law but with electricity.

 While doing the analysis from the movie we calculated an equation to show the relationship between the force and distances charges of electricity are affected. As seen in the image the ball received an angle change and like the image before we used the knowledge prior with the equation to make one relating to the force and distance. This is the equation we plugged into LoggerPro to produce the Electrostatic Force vs. Separation Distance.

 This is the graph of the experiment that shows the relationship between the electrostatic force and the distance which is inversely proportional to each other. The thing is we had to find our own using the power fit model and showing it was close to the increments of 10^-5 and close to -2. As a result from the fit we came to our vales of A: 5.0*10^-6 and B:-2.50 to plug into the Coulomb's Law equation.

 This picture shows how we used the information of the graph to relate it to coulombs' Law using the force to find the charges of each the variable in the movie. It shows the conclusions we came up with the questions in the lab manual and how the gravitational force is the same because we considered a charge to be like a mass showing the exact equation but instead of gravity being the force it is the electricity that is being done.  Our charges came out to be q=2.36*10^-8 Coulombs. 

The last part of the lab was seeing how the different charges interacted with each other and how one attracts and the other repels. And being to apply the new equation of Coulomb's with charges in different situations and distance that separates them to see the electrostatic force.

Day 6 Lab

The Diesel Cycle

In this case of the lab blog we placed the image of a complete Diesel cycle after the quiz on Wednesday. There are many cycles in which we should know and practice the relationship with the ideal gas law to know how to solve the values.

This is the diesel cycle completed with the values of P, V, T and also the heat(Q) and the work. Now with the addition of entropy we could calculated any value unless its an adiabatic process. In the end I calculated the total efficiency of the cycle which turned out to be the value of 62.47%.

The image above shows the calculations of each point and transitions to find the appropriate values in which the end of the cycle we want delta U to be zero or close as zero. However, for the values that we received was 2.2 for the total cycle and the efficiency we got around 62.47%.   

 

Day 5 Lab 03/10/14

Gas Cycles:

In this lab we discussed how different situations are affected by the addition of heat or the energy present. A demo with a rubber band doing work by lifting cans up and down by allowing the rubber to expand and contract by using a heat gun. Also finding and defining the use of thermal efficiency to determine the net work done in a system by using n. However the main purpose of the lab was the different heat engines using the gas cycles to operate by solving them in different points of the cycle and their transition points. Then finding the work done in a PV graph using the integration method even though some may not have a defined shape in heat engines.

This is the set up for the experiment or demo of the rubber band being able to expand and contract when heat is applied although the experiment did not work because it was not rubber we came to conclusion that it works like a heat engine because it does work at certain times of the process when placed in hot and cold situations. 

The pic reveals the prediction of our group when it came to the demo of the rubber band using heat to lift cans up and down using our explanation in the picture to describe each step of the system. 

 We analyzed a heat engine using the gas law to work doing a scenario in the lab manual. By developing a PV graph we were able to calculate the work and energy done in the system by using the points and transitions to see what kind of heat engine used. The engines use the gases like isobaric, isochoric, isothermal and adiabatic process in the steps to be able to operate by the work done.

 A PV diagram prediction of the situation described in the lab notebook using the gas laws to move from point to point and each one has its certain transition like a constant pressure and constant volume.

 This is the same PV diagram from above but this one has all the calculated problems and questions from the notebook where we able to find the work, het energy, internal energy and the total change in that energy using the points and transition points as well.

 We know that Eint = 3/2nRT so we were able to apply to each of the points to find the values to find the total which were: E1=3060J, E2=-3450J, E3=-2730J, and E4=2760 J and also we used the different properties of each situation like isobaric and adiabatic to find the work and energy at the transition points. In the end the result was the net Work for the whole engine process in which all the work is added to each other resulting 460 Joules.


 The second part of the lab was the mass lifting syringe were a mass is used on a syringe to find the work done by the engine cycle. We have done this lab prior to this lab showing that when the flask is in the cold water the plunger drops and when placed in the hot water the plunger rises from the initial volume to a higher point. In this case we do the experiment and make A PV diagram to find the values like in a gas cycles.

 This is a prediction done by the group what we expected the graph to look using the situation in the book and using our prior knowledge of the experiment to make a reasonable prediction of the cycle.

 The experiment set up in order to find the work done by the syringe or system when the flask closed with an amount of air in different temperature baths to move the syringe up or down to see the amount of work in the system. 

After doing the experiment the data was recorded to show this PV graph revealing that our graph was a bit off due to the flat points of our lab. In this graph it shows that there is no constant pressure or flat interval in the graph and that is what the actual graph result is to find the calculated values properly. 

The last part of the lab was doing Active Physics pertaining to the heat capacity, describing and showing different scenarios using the demo. Each of the activities had it questions in order to understand what is being done and at the end combining all of them to be able to make a conclusion of finding C which is the value 5/2R.

This a screenshot of the activity to show the different ways a person can use this to answer the questions in the lab notebook to find the heat, heat capacity and the temperature changing. When doing all the of the activities we were able to make a relationship between all of them to do question 8 to find 5/2R.

 

This is the Carnot cycle with a given PV diagram and like the one before being able to use the gas laws on the points and transition points to find each of the values need to show like work and internal energy of the cycle process.

Day 4 Lab 03/05/14

Gas Processes and Properties

After learning the ideal gas law and the relationships it relies on to work under the certain circumstances. In this lab we conducted an experiment with a fire syringe igniter and a piece of cotton. This lab was to show the adiabatic process were the total energy(Q) equals zero, by showing a closed of syringe with certain temperature. When doing the experiment the things that changed were the pressure and volume by pushing down on the syringe causing internal heat energy which as a result caused a spark. The temperature increased the closed amount of air in the syringe is pushed down with pressure and the amount of volume is changed.

This is the equipment used to conduct the experiment by pushing down on the syringe with a closed amount of air causing a spark of fire in the inner tube. We conducted the experiment in order to find the final temperature in the cylinder by using the other known variables.

 The uncertainties in this experiment would be the measurements of the length of the initial and final temperature because since it was an estimation on how long the tube is when stretched out to begin the experiment although it was easier and more accurate than the final. It is because at its final length in the syringe it has to be pushed down as much as it can which as a result it was difficult to be accurate measuring the small amount of space using the equipment and using an estimation by an eye. The other estimation we had to eyeball was the inner radius of the cylinder in order to have a least amount of error and uncertainty in our final calculation to determine the final temperature of the cylinder.

This is a video of the conduction of the experiment using the fire syringe in order to find the final temperature of the cylinder. This shows that the only things that changes is the amount of pressure being pressed down fast and the amount of volume that has changed when pushed down and the temperature. We were surprised to have received a big number according to our calculations however it made sense when it came to the real value which in Fahrenheit, 451 degrees, is the temperature where paper burns. The value we had due to the uncertainties from above we were able to determine we were around the ballpark when it came to our calculations to find the final temperature which were 2590.6 Kelvins = 4203 degrees Fahrenheit. In the time of 0:33 in the video you are able to see the spark of fire when the plunger is being pushed down showing an adiabatic process when the system is insulated and the work comes from U which in this case the changes.





This is the group's calculations and measured known values in order to find the final temperature of the cylinder which was in our case 2590.6 Kelvins. The way we were able to solve this experiment numbers was using the relationship for an adiabatic process concerning the temperature and volume. The adiabatic process is when the energy Q is zero and there is only work done by the system.

This shows the activity done on Active Physics to show the characteristics of each of the processes. In this case is a picture of an isobaric process were the pressure is constant while the other variables change. As you run the activity, you see a pressure being applied showing the relationship between volume and temperature to be linear going down when ran. Q=nCpT and W=SnRdT



This demo reveals an isochoric process in which the volume is constant and the changes were applied to pressure and volume. In the demo it reveals the relationship between pressure and temperature are linear increasing in the red line. The Q=nCvT and the work applied is zero. 



This demo shows the isothermal process in which the temperature remains constant and shows that the graph is a curved decreasing line. A pressure is being applied to a volume were in the end which is like the ideal gas law. In this process the Q and the work apply the same equation to express the values which is nRTln(V2/V1).

 

 This the group's calculations and answers to the questions from 1 through 6 that show the appropriate graphs to each of the processes. And question 3 is a problem in which an isobaric process is involved using the ideal gas law to find the answer. As well as the other questions were 5 is a constant volume problem and the last which is shown in the pic below is constant temperature. 4. Answer: 25.1 dm^3;       5. 126 kPa

As explained in the caption above this is question 6, the group applied the constant temperature process were they gave a pressure and two volumes using the isothermal process to find the final pressure of the system. The answer we received from the problem is 248 kPa.

This is a demonstration of placing a PVC pipe inside a flask containing a burning candle to see the affects of the PVC pipe and below is an image showing our explanation to the experiment on why the candle burned out when removed.

 

 

Day 3 Lab March 03, 2014

Volume vs. Temperature:

In the prior lab we went over two of the relationships of the ideal gas law and in this lab is to show the volume vs. temperature. In order to find the relationship we had a syringe connected to a flask and placing in three different temperature baths. This was done to find the change of the cc(cubic centimeter) of the syringe depending on the temperature of the water. As a result we found that both volume and temperature have a linear relationship and now having the three relationships, we were able to see how the ideal gas law's components.





 

This is the set up of the experiment in order to find the relationship between volume and temperature, which turned out to be directly proportional.

 

 

The pressure stays constant in Charles Law even though the volume changes is because the pressure is sealed using the flask in which only the gas particles(water vapors) start increasing the heat causing the syringe to start moving.

 

 

 

 

 

 Another picture of the lab set up and procedure using the equipment to find the way temperature affects the volume change in the syringe cut off with same constant pressure, Charles Law.

 

 

 The uncertainty part or value of this lab was the size of the flask, which is the volume value at the beginning it was too big, 139 cm^3, giving inconsistent values causing for the use of a smaller flask with a new volume of 39.9 cm^3. Also part of the problem of the beginning of the lab was temperature of the water because when it was too hot the syringe popped out and when it was too cold, the syringe went down all the way; as a result we had to fluctuate the water temperature enough to have a value within a 10 degree change to have a consistent and appropriate amount of volume moving in the syringe.

 

 

The group's calculations and data points of the experiment in different temperature baths, also the graph showing the relationship temperature vs. volume having the units of cm^3/K. In order to find the coefficient  the slope was used to find the units.

The slope of the volume vs. temperature is the constant  V1/T1 = V2/T2 because in this scenario the pressure is constant.

We found the units of the coefficient to be in cm^3/K however there is constant R =8.314 atm*L/mol*K  where the pressure is constant and described in the ideal gas laws. The variable n is for the moles of the material within the experiment.

 

 

The three relationships between pressure, volume, and temperature to manipulate the equations to come up with the ideal gas law. The constant rate is 8.314 Pa*cm^3/mol*K.  

 

 

 

 

 The lab set up with the syringe and flask to find the relationship between the volume and temperature, which resulted to be directly proportional.