This video is about systematic and random errors.
We will discuss errors during measurement, systematic errors, and random errors.
When we measure something not only in physics, but anywhere else in life,
we never get an exactly accurate and precise result.
In other words, our measurement will always be at least a bit off.
This is caused by measurement errors, which in turn lead to uncertainties in our measurement data.
Two examples are measuring the mess of an object on a scale,
and measuring the time it takes for a ball to roll down a slope.
Errors in the mess might be the result of an uncalybreaded scale,
while the time we measure for a ball to roll down a slope,
is usually affected by our reaction time.
There are two types of errors we consider in physics.
Systematic errors and random errors.
Let's start by discussing systematic errors.
Systematic errors, as the name suggests, are caused by the system that we use to make measurement.
These errors are very often due to faulty equipment.
An example is a so-called zero error on a scale.
This is high zero error looks like on an analog scale.
Before using this scale to measure something,
the pointer, the arrow, should be pointing at zero.
As you can see, the pointer on this scale is below zero.
This will cause all measurements to be smaller than the actual value.
In other words, a systematic error results in the same constant error for all measurement values.
If you have done science experiments, in some of them you have probably carried out repeated readings,
or trials, and then found the average or mean of these results.
An important point to remember here is that repeated readings or trials do not remove systematic errors.
This makes sense because if every reading or trial has the same error,
then their average will also have the same error.
The only way to remove or minimize systematic errors is to check your equipment
and verify that it's working properly.
Finally, you have probably heard a term accurate when describing measurements.
When a measurement is accurate, it means that it has small systematic errors.
It might be a good idea to add this word to your physics vocabulary.
Next, let's discuss random errors.
These are errors that are caused by environmental or procedural limitations.
An example is small changes in posture when measuring the height of someone.
Let's assume that the actual height of a person is 181.3 cm.
We measure the height of this person on four different days in a row and get the following values.
Two of these values are smaller than two are larger than the actual value.
So random error means that the results are clustered around the same value,
some larger and some smaller than the actual value.
In order to avoid or minimize random errors, we can take repeated readings or trials
and then calculate the average or mean of these results.
You have most likely done this in previous science experiments.
And finally, a word for your physics vocabulary,
measurements with small random errors are said to be precise.
Let's summarize what we have covered.
We have seen that measurements always have errors,
sometimes small, sometimes large, which lead to uncertainties in the data that we collected.
We discussed systematic errors, which are caused by the measurement system that we use,
and this is very often faulty equipment.
Systematic errors result in the same constant error in all measurement values,
and these errors are not removed by repeated readings or trials.
They can only be minimized by checking and verifying equipment.
Measurements that have small systematic errors are said to be accurate.
We also covered random errors, which are due to environmental or procedural limitations.
In other words, these errors occur not because of the equipment,
but often because of how we use the equipment.
Random errors cause results that are clustered around the same value,
and can be minimized by taking repeated readings or trials and calculating the mean.
You have almost surely done this in previous science experiments.
Finally, measurements with small random errors are said to be precise.
This completes our discussion of systematic and random errors.
In the next video, we will learn how to record and work with uncertainties.