Practical

Practical

1. Measuring tools

   • 1. measuring tape for distances
   • 2. micrometer for small lengths and thickness
   • 3. stopwatch for time intervals
   • 4 thermometers for temperatures
   • 5. balance for masses
   • 6. ammeter for current intensity
   • 7. voltmeter for potential difference

2. Precautions

   • Mistakes and errors
     • Systematic experimental errors
       • Parallax error occur by looking with an angle to the scale
         • Align of eyes perpendicular to the scale
       • Zero error when the scale does not start from zero
         • Pre-calibrating instruments to adjust future readings and use of zero reset button
     • Uncertainties of measurements as the exact value cannot be justified (specific significant figure) and precise
       • the result is accurate if it close to the true value of quantity
     • Insufficiently controlled values that affect the dependant value
     • Random human errors of measuring and recording
   • Safety
     • 1. Eye protection
     • 2. Safe support
     • 3. Low current dry wires
   • Repeat the experiment and take averge
   • Respect to the reactio time so take reading of several takes then divide to be closer to the true value
   • Get rid of anomalous results

3. Experimental accuracy

   • If the values have differences less than 10% they are close enough to be accepted within the limit of experimental accuracy
   • If the values have difference more than 10% they are too far to be explained within the limit of experimental accuracy

4. Variables

   • Independent variable is changed by the experimenter to know its effect plotted on X-axis
   • Dependent variable is the outcome that is measured from the experiment each time the independent variable is changed plotted on the Y-axis
   • The control variables can affect the dependent variable, so they need to be kept constant during the experiment for accuracy (environmental conditions)