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King E

What is the correct definition of zero error?

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Is this the correct definition of zero error?

The systematic error in a measuring instrument due to non-uniform or wrongly marked graduation due to which a measurement may be less or greater than actual measurement is called zero error of the measuring instrument.

 

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43 minutes ago, King E said:

Is this the correct definition of zero error?

It seems slightly off from what I recall.

I'll try a hint since this is homework section:

A: Let's say an analog meter shows 101 when value really is 100. The same meter shows 0 when actual value is 0. Does that indicate that the meter have a zero error or not?

B: Lets say a meter shows -1 when actual value is 0. The same meter shows 100 when value really is 100. Does that indicated that the meter have a zero error or not?

I would say that your definition states that A and B above are zero errors. AFAIK only A or B is a zero error. 

 

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'Zero error' is the degree of error at the zero mark. Does that agree with the statement you posted?

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16 minutes ago, Ghideon said:

It seems slightly off from what I recall.

I'll try a hint since this is homework section:

A: Let's say an analog meter shows 101 when value really is 100. The same meter shows 0 when actual value is 0. Does that indicate that the meter have a zero error or not?

B: Lets say a meter shows -1 when actual value is 0. The same meter shows 100 when value really is 100. Does that indicated that the meter have a zero error or not?

I would say that your definition states that A and B above are zero errors. AFAIK only A or B is a zero error. 

 

I agree that the OP definition is not quite right, but both your  A and B examples have two errors.

1 hour ago, King E said:

Is this the correct definition of zero error?

The systematic error in a measuring instrument due to non-uniform or wrongly marked graduation due to which a measurement may be less or greater than actual measurement is called zero error of the measuring instrument.

 

Yes a zero error is a systematic error but it is not due to a wrongly marked or non uniform graduation and yes it can result in an increased or decreased actual measurement.

A simple example of a zero error would be dirt on the pan of an otherwise accurate weighing scale.

 

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11 minutes ago, studiot said:

I agree that the OP definition is not quite right, but both your  A and B examples have two errors.

Yes a zero error is a systematic error but it is not due to a wrongly marked or non uniform graduation and yes it can result in an increased or decreased actual measurement.

A simple example of a zero error would be dirt on the pan of an otherwise accurate weighing scale.

 

So “The error which occurs in a measuring instrument due to non-leveling of scales on zero point is known as zero error”?

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13 minutes ago, studiot said:

I agree that the OP definition is not quite right, but both your  A and B examples have two errors.

Yes a zero error is a systematic error but it is not due to a wrongly marked or non uniform graduation and yes it can result in an increased or decreased actual measurement.

A simple example of a zero error would be dirt on the pan of an otherwise accurate weighing scale.

 

The example I read about was due to parallax error as an example.

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Ok. Everybody gave such good and precise answers (+1,+1,+1) that I didn't know of anything else to say. Except give the complementary mathematical focus, which is my favourite. Mathematically, a reading scale normally involves something like (at least for most measures within a certain range for both T and X:

T=T0+kX

Your apparatus is sensitive to X, while your theory connects it to the readings T. One example could be temperature as a function of the position of the mercury column. The zero error would be the error in T0, whether T0 be actually zero or not.

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Some more examples of zero errors.

Mark has a metre rule with a piece of chewing gum stuck on the (zero|) end.

This rule always measures too short a distance.

Melissa has a different metre rule with the first centimetre broken off.

This rule always measures too long a distance.

Johannes is slapdash in filling his burette for titrations.
Sometimes he overfills slightly, sometimes he does not quite reach the fill mark

So his titration readins could be either too high or too low.

 

Wilhelmina often bakes cakes, and weights out the flour into a old ice cream box stood on her digital scale.
However she often forgets to zero the scale plus box (this is called the tare function of the scale) so weighs out too little flour by the weight of the box.

 

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Posted (edited)
11 minutes ago, studiot said:

Some more examples of zero errors.

Mark has a metre rule with a piece of chewing gum stuck on the (zero|) end.

This rule always measures too short a distance.

Melissa has a different metre rule with the first centimetre broken off.

This rule always measures too long a distance.

Johannes is slapdash in filling his burette for titrations.
Sometimes he overfills slightly, sometimes he does not quite reach the fill mark

So his titration readins could be either too high or too low.

 

Wilhelmina often bakes cakes, and weights out the flour into a old ice cream box stood on her digital scale.
However she often forgets to zero the scale plus box (this is called the tare function of the scale) so weighs out too little flour by the weight of the box.

 

How is this a zero error since his error is not due to an inaccurate zero. He's just slapdash. If  his apparatus zero point is correct, he has the potential to measure correctly. It's his upper bound that is inaccurate not the zero point.

Edited by StringJunky

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1 hour ago, StringJunky said:

How is this a zero error since his error is not due to an inaccurate zero. He's just slapdash. If  his apparatus zero point is correct, he has the potential to measure correctly. It's his upper bound that is inaccurate not the zero point.

Burettes are filled to the zero mark which is at the top of the graduations on the tube.

The graduations increase downwards from this zero so indicating the amount run out when the tap is closed and the new level of liquid is read off.

 

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Posted (edited)
31 minutes ago, studiot said:

Burettes are filled to the zero mark which is at the top of the graduations on the tube.

The graduations increase downwards from this zero so indicating the amount run out when the tap is closed and the new level of liquid is read off.

 

It's been a long time since I've seen a burette.... clearly, I've forgotten.

Edited by StringJunky

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