Errors in experiments

1
Errors in experiments
2
How should you record errors?

• Electrical experiments
• Volt meter reading of 1.1V
• What is the error?
• 1.1V could be 1.05 to 1.15
• So the error is 0.05V
• This is written 1.10 0.05V

3
Percentage error

• To calculate the percentage error
• 0.05/1.10 x 100 4.5

4
Error in many readings

• 20 oscillations of a pendulum got readings
• 10.1, 9.9, 10.4, 10.9, 10.2 sec
• What is the average?
• 10.3 sec
• What is the error?
• Lowest reading 9.9, highest reading 10.9
• Average of the difference is 0.5
• Therefore 10.3 0.5sec

5
Mass

• If you weigh 1g of solid on a 2 decimal place
  balance the percentage error will be
• 0.01/1 x 100 1

6
Volume

• Pipette should be on the pipette
• Burette you can obtain reading to the nearest
  0.05cm3
• 0.05/25 x 100 0.2
• Volumetric flask should be on the flask