Sa4: Short Experimental Investigations & Stimulus Response

SA4: SHORT EXPERIMENTAL INVESTIGATIONS & STIMULUS RESPONSE.

Aldridge Science Department

Subject Details
Subject: / 12 Physics / Year:
Semester: / 4 / Teacher: / Mr Carson
Unit: / Electromagnetism & Electrostatics / Item: / SA4 Part A
Name:
Conditions
You must adhere to the school assessment policy.
Formulae booklet will be supplied and calculators allowed.
Show all working, neatly and well set out, in the exam booklets provided
Criterion / Knowledge and
Conceptual Understanding / Investigative
Processes / Evaluating and
Concluding
Experiment 1
Experiment 2
Experiment 3
SA4 Part B
Overall Grade

TASK:Over the next few weeks you will conduct 3 experiments investigating the following concepts:

Resistance, capacitance, capacitive reactance, impedance, RC circuits and RC time constants, half and full wave rectification with capacitor smoothing, low and high pass filters and voltage amplification.

Writing your Report

Once you have collected your data and analysed it, you can begin to compile your report. The outline and checklist for each of these sections is provided.

SECTION / Outline of Section
TITLE / An accurate, concise description of the project, which provides the reader with an idea of what the investigation is about
CONTENTS / A single page listing the contents of the report, and what page each section is on. A Table of Diagrams may also be relevant.
THEORY / A theoretical and descriptive introduction to the project. It should outline the theoretical background of the project
METHOD / An accurate description of materials used and experimental procedures, allowing the investigation to be repeated
RESULTS / A full description of all data, with use of tables and figures to summarise and present findings
ANALYSIS / The place to describe the relevance of your results and any limitations in your approach i.e. Providing the reader with an interpretation of both qualitative and quantitative data
CONCLUSION / A summary of your analysis. What are the key points that can be drawn from the results and analysis
BIBLIOGRAPHY / An alphabetical list of all sources used during the project.

EXPERIMENT 1: RC TIME CONSTANT INVESTIGATION.

TASK:

DATA COLLECTION CAN BE DONE IN PAIRS.

THE REST OF THE INVESTIGATION IS TO BE DONE INDIVIDUALLY IN CLASS.

Multimeters or the loggermate can be used to record data.

1. You are to design a simple experiment to investigate the RC time constants of three RC circuits using a DC power source. You will be provided with the appropriate equipment from which to assemble the required apparatus. You are to compare and comment on the use of different combinations and propose two justified hypotheses to test.

2. Include a description of the theory and components being used in your introduction. Include a brief discussion on why it is unwise to use a variable power pack as an input source. Calculations of time constants, done in the analysis can be referred to in the introductory theory to justify parts of your procedure. Include in your introduction, an example of where simple RC circuits are used.

3. When using resistors, record the manufacturer specifications. Check the specifications using a multimeter and comment on the specifications in your analysis.

4. You are to design appropriate circuit diagrams and, tables to show your results.

5. Discharge and charge curves are to be constructed, compared and commented upon. You should consider whether the capacitors are charging/discharging as they should by considering your predicted time constant calculations against interpolated data from your graphs. Any possible sources of error are to be considered and discussed along with any recommendations for any repeat of the experiment.

6. As part of your analysis, show calculations describing the current that would be flowing in each circuit at the instant when one time constant has elapsed during charging/discharging. Construct an excel table enabling you to use voltage data, along with resistor values, to determine the changing current in the circuit during charge/discharge(this table should be shown in the results section with a calculation example shown in the analysis section-showing any formulae used in the excel table).

ALDRIDGE SHS YEAR 12 PHYSICS SEI: ELECTRONICS EXPERIMENT 2

HALF AND FULL WAVE RECTIFICATION WITH CAPACITOR SMOOTHING

Task 2;

1. Do a risk assessment for the experiment explaining any dangers.

2. Do background research on the application of half and full wave rectifiers.

Investigate the use of capacitors as rectifier smoothers.

3. Research, schematically reproduce and build the circuits for half and full wave rectification using diodes and suitable resistors. Check with your teacher before proceeding. In your diagrams, clearly show which parts of the circuit are conducting by showing the flow of current.

4. Modify your diagrams and circuits by introducing a capacitor into each circuit. Again, have your circuit checked before proceeding.

5. Record the input voltage(RMS) and size of the resistors used.

6. Using the CRO, investigate the wave form of the unsmoothed half and full wave rectifiers you have built. Try and capture an image of the output for your results. Also draw the output for both explaining the drop in the amplitude.

7. Now, after formulating an hypothesis about the effect of different sized capacitors, investigate the smoothed wave forms of the two circuits with different capacitors.

8. Record the ripple amplitude for each case. Record the peak voltage and explain your results.

9. In your conclusion, comment on the manufacturers specifications for the capacitors.

ALDRIDGE SHS YEAR 12 PHYSICS SEI: ELECTRONICS EXPERIMENT 3

APPLICATIONS AND INVESTIGATION OF LOW & HIGH PASS FILTERS

Task 3:

1. Do background research on the application and basic theory behind the

operation of low and high pass filters as well as band pass filters.

Give a brief description of what is meant by “Fourier” analysis of an audio

signal.

2. Design and draw a circuit diagram for a low pass filter. Show all appropriate

calculations using the equation:. Choose a suitable frequency.

3. Build the circuit and analyse the CRO signal. Check the voltage output to see if

it fits the relationship Vo = 0.707Vs. Record qualitative observations and try to

capture and image of Vo at the cut off frequency.

4. Repeat steps 2 and 3 for a high pass filter.

5. Repeat steps 2 and 3 for a band pass filter

6. You will be given your own individual audacity file containing “white” noise

and your own specific “rogue” frequency. You are to analyse the signal on the

Labquest and run the Fourier Analysis option to identify your special

frequency. Explain how you did this(identified your frequency).

7. You are to design a bandpass filter which will cut out all other frequencies,

other than your own frequency. If you have successfully done this, you will

notice that when you play your track back it will be a series of noise “dots” and

“dashes”. This is a morse code message specific to you. Identify this message

and include it in your analysis.

8. Show a circuit diagram of your bandpass filter. Include screen captures from

the labquest of all appropriate wave forms and graphs. All relevant calculations

should be included to assist with justification. Use multimeter to measure RMS output.

Risk Assessment Form

A. IDENTIFY THE CHEMICAL HAZARDS IN THIS EXPERIMENT.

LIST THE CHEMICALS / Conc % / LIST SPECIFIC HAZARD INFORMATION
(ie Toxic, irritant, corrosive, carcinogen, flammable oxidising, explosive)
[Ask teacher for information from MSDS] / POSSIBLE EXPOSURE ROUTES
Inhalation, absorption, ingestion. / Supervision
Level
(A,B,C)
Refer guide / RISK Rating
(1-7)
Refer guide
REACTANTS
PRODUCTS

B. IDENTIFY HAZARDSOTHER THAN CHEMICALS THAT MAY EXIST IN THIS EXPERIMENT.

Hazard Category / Tick.
If exists / Hazard Details.
Give brief description. / Supervision
Level
(A,B,C)
Refer guide / RISK Rating
(1-7)
Refer guide
Pathogenic microorganisms (known or unknown)
Animal tissue or fluids.
Cuts. (eg scalpels, knives, glass tube),
Eye Damage non- chemical. (eg dusts, fumes, lasers)
Slips / trips.(eg possible wet floor, leads etc)
Falling objects (eg: tall apparatus, archery)
Ignition source (eg LPG bunsens, candles, matches).
Moving parts (eg blender, centrifuge)
Heat, (eg: ovens, hot plates, water).
Cold. (eg: Liquid N).
Pressure or vacuum.
Noise
Electricity. (any ac electrical equipment).
Ionising radiation. (eg: radio isotopes).
Non- ionising radiation. (eg Laser, UV and EMR)
Chemical
No Hazards Identified

C. INDICATE HAZARD CONTROL MEASURES TO BE IMPLEMENTED FOR THIS EXPERIMENT.

(Tick as appropriate)

NB: It is expected that laboratory rules are adhered to at all times, and as such, covered shoes, tying back of long hair, and washing of hands at the end of the practical are always implemented and are not included here as extra controls.

HAZARDS / Training / Admin Controls / Separation / Protective Clothing
As from
Tables A & B above / Require direct safety instruction from teacher. / Be taught technique prior to activity. / Have a qualified person perform activity. / Create suitable distance or barrier to hazard. / Use fume cupboard / Use natural ventilation / Use tongs / Wear lab aprons / Wear Latex Gloves / Wear Safety Glasses / Use heat gloves
N.B. If other control procedures are required, prepare and attach plans to this document

D. OVERALL RISK RATING FOR ACTIVITY (Tick as appropriate) – Refer guide

Rating 1 / Rating 2 / Rating 3 / Rating 4 / Rating 5 / Rating 6 / Rating 7

E. OVERALLSUPERVISION LEVEL REQUIRED FOR ACTIVITY(Tick as appropriate) – Refer guide

NB: If the appropriately experienced supervisor is not available the experiment must not proceed.

Level A / Level B / Level C

Approved by the teacher ______Date ______

EXPERIMENTAL INVESTIGATIONS.

Risk Assessment Guide

Supervision Rating

Supervision Level / Supervision Requirements
Level A – High Risk
Activities which DO involve ANY of the following:

high temperatures or very low temperatures, (eg liquid nitrogen)
high pressures or low vacuums,
hazardous substances, ( toxic chemicals)
highly corrosive substances
highly volatile and/or highly flammable chemicals
high voltage electricity (static and/or current)
radiation emitters
hazardous biological materials and
high speed mechanical and/or moving devices and objects.

A registered teacher with competence in the activity

An adult with competence in the activity

Competence:
Knowledge of chemical and equipment safety and has safety training relevant to the activity.
AND
Demonstrated ability to use and apply safety standards with respect to the equipment, techniques and chemicals specific to this activity.
Level B – Medium Risk
Activities which DO involve ANY of the following:

heat
pressure or vacuums
acids or other corrosive materials of low concentration
volatile and/or flammable chemicals
mains voltage power sources
biological materials
low speed mechanical and/or moving devices or objects

A registered teacher with specific experience in the activity.

An adult with specific experience in the activity.

Specific Experience:
Previous involvement with the hazard causing items/techniques.
AND
Knowledge of the hazards and safety responses to the hazards.
Level C – Low Risk
Activities which DO NOT involve ANY item listed in Level A and/or Level B: /

A registered teacher with knowledge of the activity and the potential hazards.

An adult with knowledge of the activity and the potential hazards.

Risk Rating

Consider the hazard with respect to the estimated likelihood of an occurrence and the consequences to ANY person/s in the area should something go wrong.

CONSEQUENCES OF OCCURANCE
LIKELIHOOD OF OCCURANCE / Extreme.
Death, permanent disability or illness. / Major. Serious Bodily Injury / Moderate Casualty Treatment / Minor
First Aid Treat Only / Insignificant
No injury likely
Very High. Almost certain / 1 / 1 / 1 / 2 / 4
High Likely / 1 / 1 / 2 / 3 / 4
Moderate. Possible. / 1 / 2 / 3 / 3 / 5
Low. Unlikely. / 1 / 2 / 3 / 5 / 6
Rare. Very unlikely / 2 / 2 / 5 / 6 / 7

Actions Due To Risk Rating

Risk Rating / Risk term / Action
1 / Very high / DO NOT PROCEED. Find appropriate substitute practical.
2 or 3 / High / Significant controls MUST be implemented.
Controls may include all or some of: prior learning of technique to ensure competence. Receive instruction on risk and safety procedures and/or phrases from MSDS on chemical hazards. Use appropriate design elements in the activity to reduce risk eg. fumecupboard, barriers, personal protection equipment
4 or 5 / Med / Controls should be implemented.
Controls may include receiving technique instruction and/or using personal protection equipment.
6 or 7 / Low / Only personal protection equipment may be necessary.

Student Ownership Statement Science

Name______

To be completed and handed in with your report.

My partners are ______

______

I feel that I contributed in a major way to the following aspects of the assignment:

______

I feel that I contributed less to the following aspects of the assignment:

______

The percentage contributions to this assignment are:

Me ______%

Partner name ______%

I certify that:

This submission is my own work. Any help received by other people has been acknowledged.

I understand that:

Plagiarism is a serious matter and that I will be penalised if this declaration is false. Plagiarism not only includes copying directly from texts, reference materials and the internet, but also includes copying other student’s work.
That I will be penalised for gaining unfair assistance such as from other students, parents and guardians.
Work submitted after the due date will incur a penalty in line with this school’s assignment policy.
Application for extension must be sought three days before due date except in exceptional circumstances.

Signature: ______

FRAMEWORK SHEET NAME: ______

Partner: (if applicable) ______

What aspect of the topic do you plan to investigate? ______

______

What is/are your hypothesis/es? ______

______

What are the variables? ______

______

Which variable are you investigating? ______

How will you control the others? ______

______

How will you ensure your results are not 'flukes'? ______

______

Outline your method. . ______

______

What equipment will you need? ______

______

What do I already know about this aspect? ______

______

What do I need to find out about this aspect? ______

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What results will support your hypothesis? ______

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What results will refute your hypothesis? ______

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