WHY DO SCIENTISTS TAKE MEASUREMENTS ?

MEASUREMENTS

Every measurement is an Estimate.

Subject to the error of the instrument or the error of the person measuring.

The condition during measurement is also afactor. Affect person or instrument.

Ex: rain, wind, temperature, instrument

Measurement error

Parallax – error caused by viewing an object at an

angle.

Measurement error

Meniscus – curved surface of a liquid in a container caused by the attraction of the liquid to the container

Accuracy - how close a measurement is to a specific standardPrecision – ability to get the same

measurement repeatedly.

how close measurements are to each other.

accurate preciseaccurate &precise

Significant figures, or digits, are the amount of digits that are accurate in a calculation.

This is determined by the number of digits in the numbers of a calculation.

The rules for determining significant figures are below.

All non-zero numbers are significant

A number having all portions before and after the decimal point are significant.

Zeroes at the end of a number that does have a decimal point are significant.

The decimal point makes the zeroes significant.In a decimal number, the last zero or number measured is significant.

Zeroes at the end of a number that does not have a decimal point are not significant.

In a decimal number starting with zeroes, the zeroes are not significant.

ADDING AND SUBTRACTING SIGNIFICANT FIGURES

Numbers that are added or subtracted should have the answer rounded to the decimal place of the number having the fewest number of DECIMAL PLACES.

MULTIPLICATION AND DIVISION OF SIGNIFICANT FIGURES

Numbers that are multiplied or divided should have the answer rounded to the decimal place of the number having the fewest number of SIGNIFICANT FIGURES.