1. WHY DO SCIENTISTS TAKE MEASUREMENTS ?

5. MEASUREMENTS Every measurement is an ESTIMATE.
Measurements are subject to the error of: the instrument instrument error
the person measuring human error
the conditions or method during
measurement are also a factor.
Affect person or instrument.
method error
Ex: rain, wind, temperature, instrument

6. Measurement error Parallax – error caused by viewing an object at an
angle.

7. Measurement error
Meniscus – curved surface of a liquid in a container caused by the attraction of the liquid to the container

8. Accuracy - how close a measurement is to a specific standard
Precision – ability to get the same measurement repeatedly.
how close measurements are to each other.
accurate &
precise
accurate
precise

9. 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 as follows:
All non-zero numbers are significant.
All non-zero number having all portions before and after the decimal point are significant, including zeros in between.
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.

10. 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.