Measuring physical quantities
A physical quantity can be measured and written as a number with a unit.
Scale division is the value of one smallest division between marks.
Error is the unavoidable difference between a measured value and the true value.
Reading = number + unit
Division value = (large mark − small mark) / number of divisions between them
Several measurements → arithmetic mean
Pick the symbol for the quantity.
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Temperature
Quantity symbol?
The red mark is the edge of the object (ruler) or the liquid level (thermometer). Read the value at that mark.
Thermometer 0–100 °C
Read the scale at the marker (red line).
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↑ liquid level
0
10
20
30
40
50
60
70
80
90
100
Scale (°C)· division: 1 °C
Reading:°C
Find the division value and the reading.
Scale 0–5 s, steps of 0.1 s
Read the scale at the marker (red line).
↑ marker
0
1
2
3
4
5
Scale (s)· division: 0.1 s
Reading:s
Division value:s
Calculate the arithmetic mean of the readings.
Readings:
2.122.22.1
Arithmetic mean of readings (enter a number)