- No measurement is exact
- all estimates are only
__best estimates__, which have some degree of uncertainty - you can only get an exact number when you're counting objects

__Absolute Uncertainty__, the uncertainty expressed in the units of measurement, not as a ratio

Method 1

- Make at least 3 measurements
- Calculate the average
- The absolute uncertainty= the largest difference between the average and the lowest/ highest reasonable measurement

- When making a measurement, always measure to the best precision that is possible
- You should estimate the measurement to a fraction of 0.1 of the smallest segment on the instuments scale
- On a ruler, the smallest segment is 1mm. The best precision should be to break this into 10 equal pieces. (0.1mm)

__Relative Uncertainty and Sigfigs__

Relative uncertainty = absolute uncertainty

- Can be expressed in percent (%)
- Or expressed using sigfigs
- The number of sigfigs indicates the relative uncertainty

__Try some practice questions:__Find the absolute uncertainty:

__Trial #__

__Mass of juice boxes__

1 200.35

2 200.34

3 200.34

4 200.38

5 200.33

__Trial#__

__Mass of a water jug__

1 500.29

2 500.30

3 500.32

4 500.24

5 500.30

-Lauren

## No comments:

## Post a Comment