Measuring Instruments Flashcards
Instrument
What are the instruments used to measure length?
there are 4
Ruler
Measuring Tape
Vernier Caliper
Micrometer Screw gauge
Micrometer & Vernier Caliper
Range of a micrometer screw gauge & vernier caliper measure?
2 decimal places
ie. 0.01
Ruler & Measuring Tape
Range of a ruler & measuring tape measure?
1 decimal place
ie. 0.1
Accuracy
Define accuracy
How close a measured value is to a true value.
Precision
Define Precision
The degree of exactness of a measurement.
Errors
Characteristics of random errors
Big random errors have high accuracy of average value, high uncertainty of single measurement.
accidental
Errors
Characteristics of systematic errors
Big systematic errors, good precision of measurement, low accuracy.
Has known causes
Random vs Systematic
Repeated readings
-Random errors in repeated readings cannot be repeated excatly.
-Systematic errors ing reading are constantly too high & too low.
Random vs Systematic
Correctablilty
-Random errors can never be eliminated but can be reduced by taking multiple readings.
- Systematic errors has know causes & can be corrected.
Random vs Systematic
Reason/Cause
- Random errors are caused by experimental errors.
- Systematic errors are because of approximation, instruments used, the environment & observations.
Random vs Systematic
What do they reduce?
- Random errors reduce precision
- Systematic errors reduce accuracy
Random vs Systematic
Examples
- Random:
Reaction time - Systematic:
Zero errors, Parallax,
Temperature, Approximation
errors.
Sensitivity
What is sensitivity in an instrument?
The sensitivity of a measuring instrument is its ability to respond quickly to a small change in value of a measurement.
smaller the min. scale division=more sensitive the measuring instrument
Linear vs Non-Linear Scales
What is the difference between linear and non- linear scales.
-Linear scales have an equal distance between divisions while non-linear scales do not
