4E/5NA Practical Skills

Name : _________________________________ ( ) Class : _________ Date: _________ _________________________________ ____________________________________________________________ _______________________ Practical Skills Worksheet Page 1 St. Patrick’s School Secondary 4 Science (Physics) Topics : Practical Skill Worksheet Making Observations and Presenting Data 1. Raw Data Raw data are readings or measurements taken directly from a measuring instrument. This is expressed to a fixed number of decimal places dictated by the units and precision of the instrument. [Refer to table below] Apparatus Smallest Division Examples Half metre or metre rule 0.1 cm 8.4 cm, 12.1 cm Vernier caliper 0.01 cm 2.75 cm, 5.38 cm Micrometer screw gauge 0.01 mm 2.10 mm, 3.26 mm Electronic balance 0.1 g 121.0 g, 86.2 g 0.01 g 121.10 g, 86.21 g Stopwatch (digital) 0.01 s 28.69 s Thermometer (-10 0C to 110 0C) 1.0 0C 23.0 0C, 29.5 0 C Measuring cylinder (100 cm3) 1.0 cm3 18.0 cm3, 7.5 cm3 Spring balance (0 – 10 N) 0.1 N 3.7 N, 5.8 N Ammeter (0 -1 A) 0.02 A 0.20 A, 0.54 A Milliammeter (0 – 100 mA) 2 mA 20 mA, 35 mA Voltmeter (0 – 5V) 0.1 V 2.5 V, 3.6 V

_________________________________ ____________________________________________________________ _______________________ Practical Skills Worksheet Page 2 2. Tabulation Example of Table with raw and processed data: Independent Variable l /m Time for 20 oscillations tave / s T /s T2 / s2 t1 / s t2 / s Guidelines: (a) Correct symbols and appropriate units are used for headings eg. length l and its unit metres are written as l/m and not as l (m). (b) The first column of the raw data should be the independent variable. (c) There should be a minimum of 5 to 6 readings for a straight line and 8 readings for a curve. (d) The independ ent variables should be arranged in increasing order and at regular intervals. (e) Measurements of dependent variable are repeated (where possible) to obtain an average value. 3. Processed Data (i) Processed data are readings obtained from calculations (usually multiplication or division) of one or more sets of raw data. For example, in the experiment to determine the period of a simple pendulum, a metre rule and a stopwatch are used to measure the length and time t1 and t2 of n oscillations of the pendulum. The values obtained are called raw data. To determine the average time tave and the period T of the pendulum, the following mathematical operations are carried out: tave = (t1 + t2) and T = tave where n = number of oscillations 2 n The average time tave and period T are called processed data. R