Experiment 1 Measurement error

【Experimental Principle】

1. Physical experiment and measurement error

1. The prevalence of measurement errors

When we measure physical quantities, due to the influence of factors such as theoretical approximation, resolution or sensitivity of experimental instruments, and instability of environmental conditions, measurement results cannot always be absolutely accurate. There is always some difference between the true value of the physical quantity to be measured and our measured value. This difference is called the measurement error. The measurement error exists in all measurements and runs through the measurement process.

2. The relationship between measurement error theory and physical experiment

To study the nature and causes of measurement errors, how to effectively reduce the impact of measurement errors on experimental results, how to scientifically express the experimental results containing measurement errors, and how to evaluate the experimental results, etc. Very important

of.

Second, accidental error and systematic error

According to the customary classification method, according to the nature of the error, the measurement error can be divided into accidental error and systematic error.

1. System error

Under the same conditions, when measuring the same physical quantity multiple times, the deviation of the measured value from the true value (including size and direction) is always the same. This type of error is called a systematic error.

2. Accidental error

Under the same conditions, due to occasional uncertain factors, each measured value fluctuates irregularly. The deviation of the measured value from the true value is large, small, and negative. Such errors are called accidental errors.

【Instruments】

equipment name

Model / Specification

Unit price (yuan)

Remarks

Race bridge comprehensive experiment instrument

DH6108

2850

DC single-arm bridge (choose one)

QJ23

880

Mains type

QJ23

730

Battery type

Handheld 4 and a half digital multimeter

DY2106

290

Measured resistance

50

Desktop 5 and a half digital multimeter

TH1951

2980

Can be purchased in moderation