What are the seven base units?
-Mass-kg
-Length-m
-Time-s
-Current-A
-Temperature-K
-Amount of substance-mol
What is random error?
The unpredictable variation in a measurement. IT can be reduced by taking repeated measurements and calculating a mean.
What is a systematic error?
A consistent shift in readings causing a deviation from the true value. This shift is due to the equipment or method being used and cannot be repeated measurements.
What is an uncertainty?
The range of values that could reasonably contain the true value of a measurement, based on the confidence an experimenter has about their result.
What is repeatability?
An experiment is said to be repeatable if the same person with the same equipment obtains the same result when doing the same experiment a number of times, over a short time period.
What is resolution?
The smallest interval that a given measuring device can measure.
What is Reproducibility?
An experiment is said to be reproducible if different people with different equipment, measuring the same quantity, getting a similar result.
How can you reduce random error?
-take repeats (at least 3) and produce a mean
-use computers/ data loggers/ cameras to reduce human error
How to reduce systematic errors?
-calibrate equipment before each use
-read meniscus at eye level
What is the equation for uncertainty?
Absolute Uncertainty / total value x 100
When adding or subtracting data what do you do with the uncertainties?
You add the absolute uncertainty
What do you do when you are multiplying or dividing data to the uncertainties?
Add the percentage uncertainty
What do you do to the uncertainty when you are raising the value to a power
Multiply the percentage uncertainty by the power
