1. How to Read and Record Measurements

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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.

10. 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

11. Now let’s practice!