How to Read and Record Measurements

Taking Measurements How do we know if a measurement is accurate (correct)? Accuracy depends on: Skill of person taking measurement Capacity of the measuring instrument

Read measurements to the full capacity of the instrument Always read to the smallest mark, and then estimate another digit beyond the smallest mark On ruler A, the smallest increment is 0.1cm, so the estimated digit should be the nearest 0.01cm On ruler B, the smallest increment is 1 cm, so the estimated digit should be the nearest 0.1cm A B __ ___ __ 1 1

On ruler A, what should be recorded as the length of the blue block? Around 0.52cm On ruler B, what should be recorded as the length of the blue block? Around 0.5cm A B __ ___ __ 1 1

What if the measured value falls on a scale marking? On ruler A, what should be recorded as the length of the blue block? Around 0.90cm If the measured value falls on a scale marking, the estimated digit should be a zero. The zero is important! Even though it doesn’t change the value of the measurement, it reflects the precision of the instrument. A B __ ___ __ 1 1

What if the measured value falls on a scale marking? On ruler A, what should be recorded as the length of the blue block? Around 1.00cm On ruler B, what should be recorded as the length of the blue block? Around 1.0cm A B __ ___ __ 1 1

How do I figure out the smallest increments on the scale? Divide the number of whole units by the number of marks between the two units on the scale For example,the number of marks between 0 and 1 (1 whole unit) or 2 and 4 (2 whole units) or 9 and 10 etc… A B __ ___ __ 1 1

How do I figure out the smallest increments on the scale? ____ 4 __ ___ ____5 Count the marks from 4 to 5 (1 whole unit)on the ruler to the right There are 10 marks Now divide 1unit/10marks= 0.1 So, the smallest increments on the scale are 0.1cm That means to estimate to the 0.01cm place

How do I figure out the smallest increments on the scale? ____ 4 __ ____5 Count the marks from 4 to 5 on the ruler to the right There are 5 marks Now divide 1unit/5marks= 0.2 So, the smallest increments on the scale are 0.2cm We could reasonably only estimate to the 0.1cm, since there isn’t a mark for every 0.1cm.

How do I figure out the smallest increments on the scale? ____ 5 __ ____10 Count the marks from 5 to 10 (5 whole units) on the ruler to the right There are 5 marks Now divide 5units/5marks= 1 So, the smallest increments on the scale are 1 cm So we would estimate to the 0.1cm

Now let’s practice!