1Q-LESSON-3-MEASUREMENTS-ACCURACY-PRECISION.pptx

2. LESSON 1: MEASUREMENTS
Topic:
SI Unit of Measurement
Accuracy and Precision

3. OBJECTIVES:
a.Explain the need for
measurements;
b.Carry out a measurements of
length, mass, and volume; and
c.Cite some situation in daily life
where measurement is important.

5. Why is it so
important to know
the science of
measurement?

6. Measurement is an integral part of
modern science as well as of
engineering, commerce, and daily
life. Measurement is often considered
a hallmark of the scientific
enterprise and a privileged source
of knowledge relative to qualitative
modes of inquiry.

7. Typically, a method used to collect data
involves measuring many things.
Understanding how any one thing is
measured is central to understanding the
entire research method.
Scientific measurement has been
defined as “rules for assigning numbers
to objects in such a way as to represent
quantities of attributes” (e.g., Nunnally, 1978, p. 3).

8. oMeasurement – is a
collection of quantitative
and numerical data that
describes a property of
an object or event.
oQuantity- is an
amount of something
and consists of a
number and a unit.

9. The International System (SI) of
Measurement is being used in
scientific measurement.
PROPERTY SI UNITS
Length Meter (m)
Mass Kilogram (kg)
Volume Cubic meter (m3
)
Time Seconds (s)
Temperature Kelvin (K)

10. Arrange the JUMBLED words.
1. REEMRMTOTEH
2. IIEWGNGH LACES
3. AERKBE
4. SMAEIUGNR APET
5. POST TWAHC

11. 1. THERMOMETER
2. WEIGHING SCALES
3. BEAKER
4. MEASURING TAPE
5. STOP WATCH

13. Examples and questions as to integrate the value of
the lesson in real-world environment/everyday living.
∙Length- in measuring the height of a
person; distances; size of cloths
∙Mass- in measuring the weight of a
person; the amount of salt or sugar
being bought.

14. Examples and questions as to integrate the value of the lesson in real-
world environment/everyday living.
∙Volume- in measuring the amount of a liquid.
∙Time- in measuring the duration of an event.
∙Temperature- in measuring the body
temperature of a person or of the atmosphere.

15. Practical Application of measurement. Cite
some situations in daily life where
measurement is important.

16. What is Accuracy and Precision?
∙Accuracy is a measure of how close a
measurement is to the correct or accepted
value of the quantity being measured.

17. oPrecision – measure of how close a
series of measurements are to one
another.

18. ACCURACY and PRECISION

19. ERRORS IN MEASUREMENT
Systematic Errors –
cause the result to be far
from the true value (low
accuracy)
Random Errors –
cause the result to be
different from each other
(low precision)

20. ACCURACY and PRECISION
Problem analysis regarding Accuracy and Precision
A student performed an analysis of a sample for its calcium content and got
the following results: 14.92%, 14.91%, 14.88%, 14.91%. The actual amount of
calcium in the sample is 15.70%. What conclusions can you draw about the
accuracy and precision of these results?
a)While precise, these results are not accurate
b)While accurate, these results are not precise
c)these results are both accurate and precise
d)these results are neither accurate nor precise
Ans: _______ ?

21. Meniscus - The meniscus (plural: menisci, from
the Greek for "crescent") is the curve in
the upper surface of a liquid close to the surface of
the container or another object, caused by surface
tension. The formation of menisci is commonly used in
surface science to measure contact angles and surface
tension.

22. *Sample analysis of accuracy and precision in the given data.
• Martin is conducting an experiment. His first test gives him a
yield of 5.2 grams. His second test gives him a yield of 1.3
grams. His third test gives him a yield of 8.5 grams. On
average, his yield is 5.0 grams, which is close to the known
yield of 5.1 grams of substance. Which of the following are
true?
a.His results are accurate but not precise
b.His results are precise but not accurate
c.His results are both accurate and precise
d.His results are neither accurate nor precise

23. SIGNIFICANT FIGURES
• Significant figures (also known as significant digits) are used to convey the
precision and accuracy of numbers. Here are the rules for determining
significant figures:
1. Non-zero digits are always significant. For example, the number 198745
contains six significant digits.
2. Zeros between any two non-zero digits are significant. Consider the
number 108.0097, which has seven significant digits.
3. Zeros to the right of a decimal point and to the left of a non-zero digit
are never significant. For instance, 0.00798 contains three significant
digits.

24. SIGNIFICANT FIGURES
• Significant figures (also known as significant digits) are used to convey the
precision and accuracy of numbers. Here are the rules for determining
significant figures:
4. Zeros to the right of a decimal point are significant only if a non-zero
digit does not follow them. In the number 20.00, all four zeros are
significant.
5. Zeros to the right of the last non-zero digit after the decimal point are
significant. For example, 0.0079800 contains five significant digits.
• Remember that significant figures help maintain the precision of
measurements and calculations.

25. You are assigned to deliver a chemical sample from
Lab A to Lab B, exactly 125.0 meters away.
You are timed by your lab supervisor. You run the
distance in 18.5 seconds while carrying a sample
that weighs 0.04500 kilograms.
Your task is to compute how fast you ran, using
only SI base units, and express your answer with
the correct number of significant figures.
PROBLEM SOLVING: # 1

26. Tasks:
Identify the SI units used for:
a. Distance
b. Time
c. Mass
Calculate your speed in m/s.
Determine how many significant figures your
final answer should have.
Explain why your answer has that number of
significant figures.

27. Next Lesson:
Lesson 4:
Laws of Chemical Changes
Dalton’s Atomic Theory