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