ERRORS IN EXPERIMENTAL MEASUREMENTS IN SCIENCE

Different types of errors

1. ERRORS IN MEASUREMENTS

2. ERROR The difference between the true value and the measured value of a quantity is known as the error of measurement.

3. Systematic Errors Instrumental errors zero error of instruments

4. Systematic Errors Instrumental errors zero error of instruments

5. Instrumental errors Zero error of instruments Faulty instruments Systematic Errors Comparing instrument with a standard one - calibration

6. Systematic Errors Error due to incorrect experimental technique pressure, temperature, humidity , wind

7. Instrumental errors Zero error of instruments Faulty instruments Systematic Errors Error due to incorrect experimental technique pressure, temperature, humidity , wind Personal errors Parallax error,

8. Systematic Errors Personal errors Parallax error,

9. Systematic Errors Personal errors Parallax error Carelessness lack of proper setting of the of apparatus

10. Instrumental errors Zero error of instruments Faulty instruments Systematic Errors Error due to incorrect experimental technique pressure, temperature, humidity , wind Personal errors Parallax error Carelessness lack of proper setting of apparatus

11. METHODS TO REDUCE SYSTEMATIC ERRORS using better instruments, improving experimental techniques, avoiding personal mistakes.

12. RANDOM ERRORS caused by unknown and unpredictable changes in the experiment Measuring blood pressure

13. METHODS TO REDUCE RANDOM ERRORS Taking more number of readings Take the average of all readings

14. Least Count Error The smallest value that can be measured by a measuring instrument is called its least count.

15. Least Count What is the length of this rod?????????? 9cm 9.5cm What is the least count of the scale????????? 1cm .5cm .1cm

16. Vernier calliper Least Count= 1 MSD/No. of divisions of vernier Least Count= .1cm/10 Least Count= .01cm

17. Screw gauge Least Count= .001cm

18. Absolute error The measurement of length gives values of 2.54 cm, 2.51 cm, 2.48 cm, 2.55 cm, and 2.52cm. Absolute error