Scientific Method 1

The Scientific MethodThe Scientific MethodByBy

Joseph A. Castellano, Ph.D.Joseph A. Castellano, Ph.D.RESEED Silicon ValleyRESEED Silicon Valley

Scientific Method 2

What is Science?What is Science?

Science is the study of natural processes called phenomena Science is the study of natural processes called phenomena that we can see, hear or touch.that we can see, hear or touch.

Science is very broad and investigates living things such as Science is very broad and investigates living things such as animals and plants as well as non-living matter and energy.animals and plants as well as non-living matter and energy.

In this class, we study Physical Science, which includes In this class, we study Physical Science, which includes chemistry, physics, astronomy, and other related topics such chemistry, physics, astronomy, and other related topics such as density.as density.

Scientific Method 3

How Scientists WorkHow Scientists Work

The two key questions that all scientists ask The two key questions that all scientists ask are WHY and HOW.are WHY and HOW.

Scientists raise questions about the world Scientists raise questions about the world around them and seek answers by making around them and seek answers by making careful observations. This often leads to an careful observations. This often leads to an initial theory or hypothesis. initial theory or hypothesis.

Scientific Method 4

The Work of ScientistsThe Work of Scientists

Scientists conduct tests Scientists conduct tests called called experiments to experiments to discover discover why and how a why and how a process works process works to test the to test the initial hypothesis. initial hypothesis.

All experiments, measurements, All experiments, measurements, and observations are and observations are

carefully carefully recorded in a notebook recorded in a notebook so that so that experimental results experimental results can be can be repeated and verified. repeated and verified.

Scientific Method 5

The Scientific MethodThe Scientific Method Scientists use experimental results to confirm Scientists use experimental results to confirm

the theory or to create a new or modified the theory or to create a new or modified theory of why and how the process works.theory of why and how the process works.

The theory is tested by how well it fits with The theory is tested by how well it fits with other other theories and predicts new findings.theories and predicts new findings.

Scientist then publish the results in Scientist then publish the results in a a scientific scientific journal so other scientists can repeat journal so other scientists can repeat and and verify the results to test the theory further.verify the results to test the theory further.

After many years of testing a theory, it may After many years of testing a theory, it may become so well accepted that it is recognized as become so well accepted that it is recognized as a a Law of Nature.Law of Nature.

Scientific Method 6

The Scientific MethodThe Scientific Method

Idea (Hypothesis)Idea (Hypothesis)

Lab ExperimentsLab Experiments ObservationsObservations MeasurementsMeasurements

Record Results – Formulate TheoryRecord Results – Formulate Theory

Scientific Method 7

The Scientific MethodThe Scientific Method

Confirm and Test TheoryConfirm and Test Theory

Publish FindingsPublish Findings

Theory Becomes a Law of NatureTheory Becomes a Law of Nature

Scientists Repeat & Verify ResultsScientists Repeat & Verify Results

New Products DevelopedNew Products Developed

Scientific Method 8

Concept of LengthConcept of Length

The standard unit of length is The standard unit of length is the the meter, identified as meter, identified as mm

Another common unit of Another common unit of length is the length is the centimeter or centimeter or cmcm

1 centimeter (cm) = 1/100 meter (m) = 1 centimeter (cm) = 1/100 meter (m) = .01 m.01 m

oror

1 meter (m) = 100 centimeters (cm) = 1 meter (m) = 100 centimeters (cm) = 100 cm100 cm

Scientific MeasurementsScientific Measurements

Scientists use the metric system in their experimentsScientists use the metric system in their experiments

Scientific Method 9

Scientific MeasurementsScientific Measurements

Standard Metric Units of LengthStandard Metric Units of Length

1,000 m 1,000 m = 1 kilometer (km) = 1 kilometer (km) ROADSROADS

100 cm 100 cm = 1 m = 1 m METRIC RULERMETRIC RULER

10 millimeters (mm)10 millimeters (mm) = 1 cm = 1 cm METRIC RULERMETRIC RULER

1,000 microns (1,000 microns (μμ)) = 1 mm = 1 mm MICROSCOPEMICROSCOPE

Scientific Method 10

Concept of MassConcept of Mass

The metric unit of mass is the The metric unit of mass is the kilogram or kgkilogram or kg

1 kilogram (kg) = 1/1000 gram (g) = 1 kilogram (kg) = 1/1000 gram (g) = .001 g.001 g

oror

1 kg = 1,000 g1 kg = 1,000 g

Concept of TimeConcept of Time

The standard unit of time is the The standard unit of time is the second or ssecond or s

Scientific MeasurementsScientific Measurements

Scientific Method 11

Standard Metric Units of MassStandard Metric Units of Mass

1,000 g 1,000 g = 1 kg = 1 kg

1,000 milligrams (mg) = 1 g 1,000 milligrams (mg) = 1 g

1,000 micrograms (1,000 micrograms (μμg)g) = 1 mg = 1 mg

1,000,000 micrograms (1,000,000 micrograms (μμg)g) = 1 g = 1 g

Scientific MeasurementsScientific Measurements

PERSON (50 – 60 kg)PERSON (50 – 60 kg)

EGG (45 – 50 g)EGG (45 – 50 g)

GRAIN OF SAND (12 GRAIN OF SAND (12 μμg)g)

Scientific Method 12

Concept of TemperatureConcept of Temperature

The standard international unit for temperature is degrees The standard international unit for temperature is degrees Celsius, designated as Celsius, designated as C C

Another unit of temperature often used by scientists is Another unit of temperature often used by scientists is Kelvin, designated as Kelvin, designated as KK. K = C + 273 . K = C + 273

Degrees Fahrenheit (Degrees Fahrenheit ( F F) is mostly used in the United ) is mostly used in the United States by the general public. States by the general public.

The conversion from F to C is: C = 5/9 ( F – The conversion from F to C is: C = 5/9 ( F – 32). 32).

Scientific Measurements: Scientific Measurements:

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Scientific Method 13

Accuracy & Precision (Reproducibility)Accuracy & Precision (Reproducibility)

Scientific Measurements Scientific Measurements

AccuracyAccuracy

How much uncertainty does your measurement How much uncertainty does your measurement have?have?

Half of the smallest interval marked on the tool Half of the smallest interval marked on the tool

See your metric ruler: if the true value is 10.17 See your metric ruler: if the true value is 10.17 centimeters and the metric ruler has millimeter marks, centimeters and the metric ruler has millimeter marks, then you can be accurate to:then you can be accurate to:

Uncertainty is not about place value, so it is wrong to say Uncertainty is not about place value, so it is wrong to say ++ .01 mm because you can’t read 1/100 mm on the tool! .01 mm because you can’t read 1/100 mm on the tool!

++ .05 cm or .05 cm or ++ .5 mm .5 mm

Scientific Method 14

Accuracy & Precision (Reproducibility)Accuracy & Precision (Reproducibility)

Scientific MeasurementsScientific Measurements

PrecisionPrecision

Do you get the same number over and over? Do you get the same number over and over?

You measure the mass of a piece of steel three times You measure the mass of a piece of steel three times and get the following results:and get the following results:

50.2 g 50.4 g 50.3 g50.2 g 50.4 g 50.3 g

The average is: (50.2 g + 50.4 g + 50.3 g) / 3 = 50.3 g The average is: (50.2 g + 50.4 g + 50.3 g) / 3 = 50.3 g

so the measurements are precise to so the measurements are precise to ++ 0.1 g 0.1 g

Note the unit g after each numberNote the unit g after each number

There are no naked numbers in science!There are no naked numbers in science!

Scientific Method 15

Accuracy & Precision (Reproducibility)Accuracy & Precision (Reproducibility)

Scientific MeasurementsScientific Measurements

There is no such thing as a perfectThere is no such thing as a perfect

measurement so it is important to know measurement so it is important to know bothboth

the accuracy (uncertainty) and precisionthe accuracy (uncertainty) and precision

(reproducibility) of the measurement.(reproducibility) of the measurement.

Scientific Method 16

Scientific CalculationsScientific CalculationsBalancing of Units Balancing of Units

When making calculations always make sure the units balance.When making calculations always make sure the units balance.Example: A runner reaches a speed ofExample: A runner reaches a speed of10 meters/second, 20 seconds after he starts.10 meters/second, 20 seconds after he starts.How far does he travel?How far does he travel?

D (distance) = V (velocity) x t (time)D (distance) = V (velocity) x t (time)

D = 10 D = 10 mm x 20 s = 200 m x 20 s = 200 m s s X

X

The answer is 200 metersThe answer is 200 meters

Scientific Method 17

The Importance of ScienceThe Importance of Science Science provides the means to improve the way Science provides the means to improve the way of of life for current and future generations of people. life for current and future generations of people.

Scientists:Scientists:

Develop new instruments and surgical Develop new instruments and surgical techniques to techniques to identify and cure diseases.identify and cure diseases.

Create new products that improve Create new products that improve communications, communications, transportation, and transportation, and entertainment.entertainment.

Ensure the cleanliness and safety of the Ensure the cleanliness and safety of the environment.environment.

Discover new drugs that improve and extend Discover new drugs that improve and extend health.health.

Scientific Method 18

The Importance of ScienceThe Importance of Science Science is at work in everyday life.Science is at work in everyday life.

An automobile’s operation involves many interrelated An automobile’s operation involves many interrelated scientific principles including electricity, mechanics, scientific principles including electricity, mechanics, chemistry, and physics.chemistry, and physics.

The calculator you use in class employs a combination The calculator you use in class employs a combination of chemistry, physics, and electronic engineering.of chemistry, physics, and electronic engineering.

The computers in our classroom use complex The computers in our classroom use complex mathematical principles, wireless communication mathematical principles, wireless communication technology, electronics, mechanics, chemicals, and more.technology, electronics, mechanics, chemicals, and more.

Understanding science will help in your future Understanding science will help in your future endeavors, regardless of what they might be. endeavors, regardless of what they might be.