Tips for Practical PapersPaper 3 Tips: Practical Test
this is what my teacher told me!!
•Do not panic if the context of the practical experiment appears unfamiliar. Whereappropriate the question paper will tell you exactly what to do and how to do it.
•If you find yourself in real difficulty setting up your practical equipment you may askyour supervisor for help, although you may lose one or more marks for this.
•There are a number of things that you can do to save time: Draw a single table foryour results in advance of taking any readings and enter your readings in the table asyou take them (so that you do not waste time having to copy them up later). This isalso important because you must record all your raw readings before you calculateand record any average readings. If the number of readings that you need to take isindicated in the question paper do not waste time by exceeding this number. Repeatyour readings, but remember that it is only necessary to repeat them once (so thatyou have two sets of values) - do not waste time repeating them more than once.
•All the raw readings of a particular quantity should be recorded to the same number ofdecimal places which should in turn be consistent with the uncertainty in the readings.
•The uncertainty in a measurement can sometimes be larger than the smallest intervalthat can be measured by the measuring equipment. For example, a stopwatch canmeasure time to a hundredth of a second, but human reaction times will mean thatthe uncertainty in the reading given by a stopwatch is (typically) 0.1s to 0.4s.
• Each column heading in your table must contain both a quantity and its unit. Forinstance if you have measured time “t” in seconds, your column heading would bewritten as “t/s” (“t in s” or “t(s)” would also be acceptable). The quantity or unit or bothmay also be written in words rather than symbols.
•The number of significant figures used in a derived quantity that you calculate fromyour raw readings should be equal in number to (or possibly one more than) thenumber of significant figures in the raw readings. For example, if you measurepotential difference and current to 2 and 3 sig figs respectively, then thecorresponding value of resistance calculated from them should be given to 2 or 3 sigfigs, but not 1 or 4. If both were measured to 3 significant figures, then the resistancecould be given to 3 (or 4) sig figs.
• When drawing your graph, do not forget to label each axis with the appropriatequantity and unit, using the same format for expressing column headings in a table.Choose a scale such that the plotted points occupy at least half the graph grid in boththe x and y directions. The x-axis scale should increase positively to the right and they-axis scale should increase positively upwards. Use a convenient scale such as 1, 2or 5 units to a 2cm square as you will then be less likely to make a mistake with theposition of your plotted points and it will be easier for you to read off points from yourgraph if you are calculating the gradient or finding an intercept.
•All your plotted points should be on the grid; points in the white margin area will beignored. Plot all your observations and ensure that they are accurate to half a smallsquare. A fine cross (or an encircled dot) drawn with a sharp pencil is acceptable, butbe careful not to obscure the position of your points by your line of best fit or otherworking.
•When drawing your line of best fit, ensure you have an even balance of points aboutthe line along its whole length. If it is a straight line, use a clear plastic rule so thatyou can see points on both sides of the line as it is being drawn.
•Show all your working when calculating a gradient. It is helpful to draw the triangleused to calculate the gradient on the graph and to clearly label the coordinates of thevertices (accurate to half a small square). These values can then be used in thegradient calculation. The length of the hypotenuse of the triangle should be greaterthan half the length of the graph line.
•If you are required to give a value for the y-intercept, it may be possible to directlyread it off from your graph from an axis where x=0. If this is not possible you caninstead calculate the y-intercept by using the equation of a straight line. In this caseyou should substitute into this equation a pair of x and y values from your line of bestfit along with your calculated value of gradient.
Gudluck to you all People!!!!
this is what my teacher told me!!
•Do not panic if the context of the practical experiment appears unfamiliar. Whereappropriate the question paper will tell you exactly what to do and how to do it.
•If you find yourself in real difficulty setting up your practical equipment you may askyour supervisor for help, although you may lose one or more marks for this.
•There are a number of things that you can do to save time: Draw a single table foryour results in advance of taking any readings and enter your readings in the table asyou take them (so that you do not waste time having to copy them up later). This isalso important because you must record all your raw readings before you calculateand record any average readings. If the number of readings that you need to take isindicated in the question paper do not waste time by exceeding this number. Repeatyour readings, but remember that it is only necessary to repeat them once (so thatyou have two sets of values) - do not waste time repeating them more than once.
•All the raw readings of a particular quantity should be recorded to the same number ofdecimal places which should in turn be consistent with the uncertainty in the readings.
•The uncertainty in a measurement can sometimes be larger than the smallest intervalthat can be measured by the measuring equipment. For example, a stopwatch canmeasure time to a hundredth of a second, but human reaction times will mean thatthe uncertainty in the reading given by a stopwatch is (typically) 0.1s to 0.4s.
• Each column heading in your table must contain both a quantity and its unit. Forinstance if you have measured time “t” in seconds, your column heading would bewritten as “t/s” (“t in s” or “t(s)” would also be acceptable). The quantity or unit or bothmay also be written in words rather than symbols.
•The number of significant figures used in a derived quantity that you calculate fromyour raw readings should be equal in number to (or possibly one more than) thenumber of significant figures in the raw readings. For example, if you measurepotential difference and current to 2 and 3 sig figs respectively, then thecorresponding value of resistance calculated from them should be given to 2 or 3 sigfigs, but not 1 or 4. If both were measured to 3 significant figures, then the resistancecould be given to 3 (or 4) sig figs.
• When drawing your graph, do not forget to label each axis with the appropriatequantity and unit, using the same format for expressing column headings in a table.Choose a scale such that the plotted points occupy at least half the graph grid in boththe x and y directions. The x-axis scale should increase positively to the right and they-axis scale should increase positively upwards. Use a convenient scale such as 1, 2or 5 units to a 2cm square as you will then be less likely to make a mistake with theposition of your plotted points and it will be easier for you to read off points from yourgraph if you are calculating the gradient or finding an intercept.
•All your plotted points should be on the grid; points in the white margin area will beignored. Plot all your observations and ensure that they are accurate to half a smallsquare. A fine cross (or an encircled dot) drawn with a sharp pencil is acceptable, butbe careful not to obscure the position of your points by your line of best fit or otherworking.
•When drawing your line of best fit, ensure you have an even balance of points aboutthe line along its whole length. If it is a straight line, use a clear plastic rule so thatyou can see points on both sides of the line as it is being drawn.
•Show all your working when calculating a gradient. It is helpful to draw the triangleused to calculate the gradient on the graph and to clearly label the coordinates of thevertices (accurate to half a small square). These values can then be used in thegradient calculation. The length of the hypotenuse of the triangle should be greaterthan half the length of the graph line.
•If you are required to give a value for the y-intercept, it may be possible to directlyread it off from your graph from an axis where x=0. If this is not possible you caninstead calculate the y-intercept by using the equation of a straight line. In this caseyou should substitute into this equation a pair of x and y values from your line of bestfit along with your calculated value of gradient.
Gudluck to you all People!!!!
