Tips Table & Observations We compiled a new list of errors and improvements for the last part of question 2 in physics paper 3. Only the first one you can use everywhere, as long as the question requires taking any type of measurement at all. These are all from the past papers marking schemes. These could be helpful if you're running out of time and had memorized these before, but please make sure these errors and improvements fit the question! 1. Error: Two readings not enough to support the conclusion Improvement: Take more sets of readings and plot a graph/compare values of k (This one works everywhere. Memorize this!) 2. Error: Large uncertainty in measured quantity because quantity is too small (like when measuring the thickness of an object) Improvement: improved method to calculate this quantity like taking more readings at different parts of the object and dividing by number of readings for an average. 3. Error: Friction with surface (apply to any object that you have to pull on a surface) Improvement: apply lubricant to surface 4. Error: (only when newton meter used horizontally!) Zero error on newton meter when used horizontally. Improvement: adjust vertical arrangement of newton meter. 5. Error: (Keeping an object at certain height with your hands for a long time) keeping "object" at a certain height difficult Improvement: use a clamp/tape. ELECTRICITY: 6. Error: Voltmeter scale not sensitive enough/not precise enough Improvement: Use a digital voltmeter/use a voltmeter that reads to 0.01 V. 7. Error: Wire not straight/wire kinked (coils) / difficulty in keeping wire straight Improvement: Tape wire to a ruler/ clamp wire. 8. Error: Contact resistance/fluctuating ammeter or voltmeter readings Improvement: Sand the crocodile clips to clean them/ tighten clips OSCILLATIONS 9. Error: Difficult to judge start/center/ end of swing / complete swing Improvement: use fiducial marks/pointer 10. Error: large uncertainty in time / time taken too short Improvement: use video and timer that captures frame by frame video 15. Error: Difficult to mark rebound height/final position Improvement: Use a high speed camera that has slow motion playback and use a data logger. ------------------------------------------------------------------------------------------------------------11. Error: Object does not travel in a straight line Improvement: Method of guiding object to travel in a straight line/narrow tube (if ball moving inside) 12: Error: (when measuring degrees in an experiment that's suspended in the air like the degrees between a rubber band when stretched) difficult to hold protractor steady Improvement: project image of the rubber band onto a screen. 13: Error: applying a force on the object when releasing it/impossible to release object without applying a force. Improvement: use an electromagnet release clamp to release the object so it falls/moves on a slope or surface under the force of its own weight. 14. Error: Air currents may cause variation in path of object (KEEP IN MIND THE MASS OF THE OBJECT AND BE REASONABLE) Improvement: Close fans and air conditioners, shield object from draughts. 16. Error: Difficult to make accurate cylinder shape Improvement: Use a cylinder mold to make and accurate shape/method of making accurate cylinder. 17. Error: inconsistent ball bounce/ball bounces (on surface) at an angle. Improvement: use a smoother brick. 18. Error: Friction at pulley Improvement: Lubricate pulley 19. Error: Retort stand moves improvement: Clamp stand to bench/table 20. Error: Labelled value of mass may not be accurate Improvement: use a top pan balance to find mass. 21. Error: Large uncertainty error in thickness Improvement: Measure more layers of paper/(object) OR use micrometer screw gauge for better precision. ------------------------------------------------------------------------------------------------------------Meter Rule: 0.1 cm = 1mm = 0.001m Vernier Caliper: 0.01cm = 0.1mm Micrometer: 0.001cm = 0.01mm Protractor: 0.1 or 0.2 degrees (depending on experiment) Time: 0.1s Important: Also google pictures of DIGITAL MULTIMETERS and learn how to use them. Good night people. Remember me in your prayers
