The parallax error also: parallax error is an observation error that arises when you look at two objects lying one behind the other and change the starting point, so that there is an apparent shift of the objects - the so-called parallax , which is only simulated by the different viewing angles.
An everyday example arises when taking a panorama picture by hand, when the photographer simply turns around his vertical axis and holds the camera a little in front of him and thus a little in front of the pivot point.
The closer objects come into the picture, the greater the shifts occur in successive recordings. In order to avoid these generally undesirable shifts, the axis of rotation should coincide with the entrance pupil of the objective used in each case. A parallax error leads to a measurement error when reading a pointer measuring device , which occurs if one does not look at the scale at a right angle. Accuracy is a measure of how close the results of an experiment agree with the true value.
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. For accurate measurement, the eye must always be placed vertically above the mark being read. This is to avoid parallax errors which will give rise to inaccurate measurement. Parallax errors affects the accuracy of the measurement. If you consistently used the incorrect angle to view the markings, your measurements will be displaced from the true values by the same amount.
This is called systematic error. However, if you used different angles to view the markings, your measurements will be displaced from the true values by different amounts. This is called random error. Parallax error is primarily caused by viewing the object at an oblique angle with respect to the scale, which makes the object appear to be at a different position on the scale.
Place the measurement device on its edge so it is level with the object being measured. If the measurement marking is above or below the object, it will magnify any parallax error caused by your line of sight being at an angle with respect to the marking.
Seek out the finest possible edge of the measurement device, or use a device with finer edges. A wider edge allows for a larger parallax error because the object could be higher or lower with respect to the true measurement marking.
Place your eye at the level of the appropriate measurement marking when measuring the level of a liquid in a graduated cylinder. Read the lower part of the curved surface of the liquid -- the meniscus -- to gain an accurate measurement and avoid parallax errors. Ask other people to take measurements.
Because parallax error is a type of random error, you can average multiple readings taken by different people to cancel out most of the parallax angle. It is likely that some readings will have positive parallax error and others will have negative error.
The average of these readings will be closer to the true measurement. Karl Wallulis has been writing since
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