Expt. 1 Measurement, Uncertainties and Errors

Errors, Uncertainties, and

Measurement

Experiment 1

Physics

The Nature of Physics

Physics has developed out of the efforts

of men and women to explain our physical

environment.

Physics encompasses a remarkable

variety of phenomena:

planetary orbits

radio and TV waves

magnetism

lasers

many more!

The Nature of Physics

Physics predicts how nature will behave

in one situation based on the results of

experimental data obtained in another

situation.

Newton’s Laws → Rocketry

Maxwell’s Equations → Telecommunications

Units

Physics experiments involve the measurement

of a variety of quantities.

These measurements should be accurate and

reproducible.• The unit of measurement should not change

• The unit of measurement can easily be duplicated

The first step in ensuring accuracy and

reproducibility is defining the units in which

the measurements are made.

Units

SI units

meter (m): unit of length

kilogram (kg): unit of mass

second (s): unit of time

Units

Units

Units

Errors, Uncertainties, and

Measurement

Experiment 1

Experiment 1: Errors, Uncertainties, and Measurement

Uncertainty: doubt in measurement

Degree of uncertainty:

1. Accuracy

2. Precision

Error: deviation from standard or accepted value

Sources of error:

1. Systematic error

2. Random error

Main Scale Reading : 27 mm

Vernier Scale Reading :

Notes on Significant Figures

Experiment 1: Errors, Uncertainties, and Measurement

Vernier caliper

Experiment 1: Errors, Uncertainties, and Measurement

Micrometer caliper

3

3

4

:

rV

Volume

n

diameterdiametermean

diametermeanreadingd

deviation

:

n

dda

deviationAverage

..

:

n

daDA

meantheofdeviationAverage

....

:

Volume

mass

100%

S

SEError