Lab 1 (Practice) Uncertainty in physics - intro to physics lab PDF

Preview

Summary

This lab was introductory and was very important to help students learn basic physics concepts such as uncertainty and error....

Description

Physics 1E03: Lab 0 Set yourself the following objectives for this week’s exercises: ● ● ● ●

Create an account with CircuitLab.com Learn to use the CircuitLab interface Design, build, and test several circuits using different circuit elements Get familiar with the system for submitting your lab assignments: CrowdMark.com

The following shows the value of all the questions in this lab: Laboratory 0 Grading Scheme Ex. 1

1.1

Points Ex. 2 Points

Totals

1.2 /1

2.1

/1

/2

/1

/2

2.2 /1

Ex. 3 Points

/0

Note: the marks for this lab are bonus marks.

/4

Exercise 1: Welcome to CircuitLab Hello, and welcome to the virtual lab component of Physics 1E03. In previous years, labs were performed in groups of 2-3, in person, with a 3-hour time limit, every 2 weeks. This year, you will be performing labs at home using the virtual circuit-building platform “CircuitLab”. Since this platform is likely new for everyone, this first lab serves as an Introduction to CircuitLab as well as CrowdMark (the website where completed assignments will be submitted). The goal of this lab is to practice using these websites, and work out any kinks such that you will have no problems with the following lab assignments.

To ensure that you have completed all steps and are comfortable with CrowdMark, we will ask you to submit several different types of files and responses. All parts of the lab that must be submitted will be written in bold and numbered based on exercise and question number. For example, when you see (1.1), this means this is the first question of the first exercise that must be submitted through CrowdMark. The rubric at the beginning of the lab will also help you ensure that all questions have been answered and submitted. The first thing you will need to do is create an account on www.CircuitLab.com . It is important that you use your McMaster email to register, and confirm that you are signing up under McMaster’s license. Below is a screenshot of the Sign Up which includes a reminder to use your McMaster email.

Note: CircuitLab may try to change your email to be @mcmaster.com rather than @mcmaster.ca . Don’t fall for it like I did the first time or you will have to start over.

Once registered, click the following button:

Then select “Student Edition” (free):

Congratulations, you are now a CircuitLab Student member. (1.1) Submit a screenshot of the CircuitLab welcome message (the very next screen after clicking the “Join Student Edition”. The next thing you need to do is watch the tutorial video on the main page (www.circuitlab.com). Don’t worry about what a square wave or a low-pass filter is for now, this is mostly to get you started with how to use the Workstation. (1.2) What were the first two resistors set to in the tutorial video? In the next exercise you will begin constructing your own circuits.

Exercise 2: Building in CircuitLab The circuits you will be building consist of five types of elements: Voltage Sources, Resistors, Capacitors, Switches and a Ground terminal. But before you build anything, let’s review what each of these elements do. Voltage Source (DC)

An ideal voltage source provides a fixed voltage to the circuit, regardless of the resistance within a circuit or the output current. NOTE:In this lab, we will assume the Voltage Source is ideal and provides Direct Current (as opposed to Alternating Current).

Resistor

A resistor is a device that reduces the current flow in a circuit.

Capacitor

A capacitor stores electrical energy as an electric field between two conductors (usually parallel conducting plates). Capacitors can be “charged” and “discharged”.

Ground

Ground is a reference point in an electrical circuit, usually defined 0 V. NOTE: all of the circuits in this lab MUST be grounded.

Switch

A circuit element that can either “open” or “close” a circuit. When a switch is closed, it is indistinguishable from a circuit wire (R = 0 Ω). When it is open, the circuit is broken and no current can flow.

The first circuit you will consider is shown below. (2.1) i) What is the Voltage provided by the Voltage Source and Resistance in this circuit? ii) Use Ohm’s Law to calculate the Current. iii) If you measure the voltage at the Circuit_1 label, what would you get? If you measured the voltage at the junction between the Resistor, Ground, and Voltage Source, what would you get? iv) Check your answers by building this circuit in CircuitLab and submit a screenshot of your circuit. If you are having trouble with the CircuitLab interface, there are many tutorials available under the Help tab (as well as the tutorial video on the homepage). Now it’s time to build circuits 2, 3, 4, and 5. In the following diagrams, Resistors are labeled with an R, Capacitors a C, Voltage Sources V, and Switches SW. Use the following figures as a guide to build your circuits, noting that the actual values for your circuit elements will not be the same as those shown in the diagrams. For Switches, you will see that there are many different switches to choose from. In this lab, use the TimeControlled Switch. For convenience, please build all of your circuits on the same sheet like in the image below. The values to be used for your circuit elements are unique to you, and based on the LAST TWO DIGITS of your STUDENT NUMBER. Example: If your student number is 41413632 and R1 = 1.XX Ω, that means R1 = 1.32 Ω. Voltage Sources V2 = V3 = V4 = V5 = 5.XX V

Resistors R2 = R4 = 2.XX Ω

Capacitors C1 = C2 = 1.XX µF

R3 = R5 = 3.XX Ω R6 = R7 = 6.XX Ω

(2.2) Build the above circuits on one worksheet and submit i) an exported PNG of your worksheet and ii) a public link to your worksheet. Be sure to label all circuit elements, and use your personalized values from the table above. If you have trouble exporting your worksheet, instructions can be found in the HELP documentation on the CircuitLab website.

Exercise 3: Making Measurements The final part of this lab is to try making some measurements. Before you can make any measurements, you have to let the program “simulate” the circuits (and calculate all of the values for you). Select SIMULATE at the bottom left of the worksheet. There are several different things you can do here, but for right now, all you need is the DC SOLVER under the DC tab. Once you run the DC SOLVER, you can click on different areas of your circuit to make measurements. Try measuring the Voltage before and after one of the resistors. Try measuring the current. Change the value of your resistors or voltage source and run the DC SOLVER again. Check your measurements again. Did they change? Spend some time playing with your circuits and make sure you are comfortable with CircuitLab. If you have any problems, remember to first consult the HELP documentation on the CircuitLab website. There are many helpful tutorials available. Oh, and before you go, refamiliarize yourself with the following rules:

Here’s how significant figures work To determine the number of significant figures in a number use the following 3 rules: 1. Non-zero digits are always significant 2. Any zeros between two significant digits are significant 3. A final zero or trailing zeros in the decimal portion ONLY are significant Example: .500 or .632000 the zeros are significant .006 or .000968 the zeros are NOT significant

For addition and subtraction use the following rules: 1. Count the number of significant figures in the decimal portion ONLY of each number in the problem 2. Add or subtract in the normal fashion 3. Your final answer may have no more significant figures to the right of the decimal than the LEAST number of significant figures in any number in the problem.

For multiplication and division use the following rule: 1. The LEAST number of significant figures in any number of the problem determines the number of significant figures in the answer. (You are now looking at the entire number, not just the decimal portion) *This means you have to be able to recognize significant figures in order to use this rule* Example: 5.26 has 3 significant figures 6.1 has 2 significant figures

This is the end of the lab. Be sure you submit all bolded portions of the lab on CrowdMark.com ....