physics workshop demystifying 9188/4 yours truly t.v madziva +263774187669 or [email protected]
TRANSCRIPT
DO YOU KNOW THIS?
• Marked out of 50There are only 3 questionsOnly 2hrs 30minQ1 &2 marked out of 18 each, and 1hr eachQ3 marked out of 14,and 30minOverrally P4 contribute 20% in weight i.e
50/250
Skills Weighting And Distribution
Factual Recall And Comprehension= 10%
Handling And Application= 50%
Deductive Reasoning And Synthesis= 40%
Experimental Skills And Investigations
• Candidates should be able to:1. Follow a detailed set or sequence of
instructions and use techniques, apparatus and materials safely and effectively
2. Make observations and measurements with due regard for precision and accuracy
3. Interpret and evaluate observations and experimental data
Continued
4. Identify a problem, design and plan investigations, evaluate methods and techniques, and suggest possible improvement;5. Record observations, measurement, methods and techniques with due regard for precision, accuracy and units
Question outline
Q1 is normally on mechanical oscillationsQ2 based on measurement of electrical
quantitiesQ3 is a design question (from any section of
the syllabus or outside) but handling of information remains the same
Expectations for each mark category
• Manipulation, measurement and observation(M)
• Presentation of Data and Observations(R)
• Graphical Work(G)
• Analysis, conclusions and Evaluation(A)
Manipulation, measurement and observation
Successful collection of data: candidates to-1. Correctly set up apparatus without assistance
from supervisor2. Follow instructions given3. Collect an appropriate quantity of data4. Repeat readings where appropriate5. Use both analogue scales and digital displays6. Make measurements using common apparatus
Manipulation, measurement and observation
Range and distribution of values1. Make measurements that span the largest
possible range of values within the limits2. Make measurements whose values are
appropriately distributed within this range
Manipulation, measurement and observation
Quality of data1. Make and record accurate measurements2. Mark will be awarded for measured data in
which the values obtained are reasonable3. The award of the mark is based on the scatter
of points on a graph4. Candidate`s data may be compared with
information supplied by supervisor or known to the examiners
Presentation of Data and observations
Table of results: layout1. Present numerical data and values in a single
table of results2. Draw up the table in advance of taking
readings so that you do not have to copy up your results
3. Use column headings that include both the quantity and the unit and that conform to accepted scientific conventions
Presentation of Data and observations
Table of results: raw data1. Record raw readings of a quantity to the
same degree of precision2. The degree of precision used should be
compatible with the measuring instrument used
Presentation of Data and observations
Table of results: calculated quantities1. Calculate other quantities from raw data to
correct number of significant figures 2. Calculated quantities should be given to the
same number of significant figures (or one more than) the measured quantity of least accuracy.
3. The number of SF may, if necessary, vary down a column of values for a calculated quantity
TABLE OF RESULTSl/cm T1/s T2/s T3/s Lg(T/s) / /S
22,5 13.21 13.78 12.92 1.1212 174.7 13.22
34,6 17.23 17.01 17.42 1.2385 299.9 17.32
45,1 23.45 24.01 24.04 1.3777 569.3 23.86
56,6 26.22 26.81 27.11 1.4224 699.6 26.45
76,3 31.23 31.28 32.01 1.5022 1009 31.78
Graphical work
Layout1. Clearly label graph axes with both quantity
and unit2. Choose scales such that the plotted points
occupy at least half of the grid in both directions
3. Use a false origin where appropriate4. Avoid holes, gaps and awkward scales
Graphical work
Plotting of points1. Plot all data points on graph grid to an
accuracy of better than half a small square2. Points should be finely drawn with a sharp
pencil but must still be visible. A fine cross or an encircled dot is suitable. A thick pencil blob is not.
3. All observations must be plotted
Graphical work
Trend line/line of best fit1. Identify when the trend of a graph is linear or
curved2. Draw straight lines of best fit or curves to show
the trend of a graph3. The trend line should show an even
distribution of points on either side of the line along its whole length
4. Avoid kinks/breaks, hairy, point to point lines
Graphical work
Gradient triangle1. When a gradient is to be determined, the
points on the line chosen for the calculation should be separated by at least half of the length of the line drawn
Graphical work
Y-intercept calculation1. In cases where the y-intercept cannot be
read directly from the y-axis, it is expected that the co-ordinates of a point on the line and the gradient will be substituted into y=mx+c
Graph
22,5 34,6 45,1 56,6 76,30
200
400
600
800
1000
1200
l/cm
t/s
Analysis, Conclusions and Evaluations
Display of calculation and reasoning1. Show working in calculations2. Justify the number of sig fig in a calculated
quantity
Analysis, Conclusions and Evaluations
Interpretation of graph1. Relate straight line graphs to y=mx+c, y=a,
y=a2. Determine the gradient3. Determine the y-intercept
Analysis, Conclusions and Evaluations
Drawing conclusions1. Draw conclusions from an experiment,
including determining the values of constants, considering whether experimental data supports a given hypothesis, and making predictions.
Analysis, Conclusions and Evaluations
Estimating uncertainties1. Estimate, quantitatively, the uncertanty in
their measurements2. Express the uncertanty in a measurement as
an actual, fractional or percentage uncertanty
Analysis, Conclusions and Evaluations
Identifying limitations1. Identify and describe the limitations in an
experimental procedure2. Identify the most significant sources of error
in an experiment
Analysis, Conclusions and Evaluations
Suggesting improvements1. Suggest modifications to an experimental
arrangement that will improve the accuracy of the expt. Be realistic.
DESIGN
Layout of the apparatus1. Include diagram of apparatus2. Only workable diagrams will score marks
DESIGN
Methods of data collection1. Describe the method to be used to vary the
independent variable2. Describe how variables are to be measured3. Describe how other variables are to be kept
constant
DESIGN
Method of analysis1. Describe how the data should be used in
order to reach a conclusion, including details of derived quantities to be calculated and graphs to be drawn as appropriate
DESIGN
Safety considerations1. Assess the risks of your experiment.2. Describe precautions that should be taken to
keep risks to a minimum.