Zero error occurs when the measuring instrument registered a reading when there should be none.
Note: You can check out Measurement Of Length for information on how to deal with zero error for vernier calipers and micrometer screw gauge.
Accuracy is a measure of how close the results of an experiment agree with the true value.
- When accurate, small systematic error
Precision is a measure of how close the results of an experiment agree with each other. It is a measure of how reproducible the results are.
- small uncertainty, increase precision, small random error.
A scalar quantity is a physical quantity with magnitude only.
A vector quantity is a physical quantity that has both magnitude and direction.