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What is a Scientist?Ms. Moore
8/17/12
Albert Einsteinphysicist
Stephen Hawkingcosmology and quantum
gravity
Scientists are…Scientist: a person who is studying or has
expert knowledge of one or more of the natural or physical sciences
Who are your favorite scientists?
How many scientists are in this room?
What is Science?Science: organized way of using evidence to learn
about the natural world
The goal of science is to investigate and understand the natural world, to explain events in the natural world, and to use those explanations to make useful predictions.
Major categories of science:Life scienceEarth sciencePhysical science
Thinking Like a ScientistThe Scientific Method: organized set of
investigationAsk a Question/ResearchForm a HypothesisTest Hypothesis/Design ExperimentRecord/Analyze Data Draw Conclusions/Report Findings
Ask a Question/ResearchMany scientific investigations begin when
someone observes an event in nature and wonders why or how it occurs.
Next, a question is proposed.
These questions lead to the investigator researching the subject and learning information about it.
Form a HypothesisHypothesis: a possible explanation for a
problem using what you know and what you observe.
A hypothesis: Made before data is gatheredPossible answer to your question
Hypothesis: ActivityWatch “The Battle at Kruger” and make a
hypothesis.
Will your hypothesis change as more data is gathered from watching the video?
Test Hypothesis/Design ExperimentTest hypothesis:
Observation: the process of gathering information about events or processes in a careful, orderly way
Experiment: tests the effect of one thing on another using controlled conditions variables: value varies/subject to change
Independent variable: value manipulated (ex. fertilizer) Dependent variable: value changes depending on response to
independent variable (ex. growth) constants: a factor that does not change when other variables
change (ex. sunlight, water, temperature, etc.) controls: standard by which the test results can be compared (ex.
unfertilized plant) Models can represent an idea event, or object to help
others understand
Record/Analyze DataOrganize the results in easy-to-read tables,
charts, and/or graphs
How would you share the information you found with others?
Is there a better way to answer the question?
Drawing Conclusions/Reporting Based on the analysis of your data, you are
now ready to draw a conclusion:You decide whether or not your hypothesis is
supported.If the data does not support the hypothesis it
should probably be revised.
Bias occurs when what the scientist expects changes how the results are viewed.Running many trials with a measurable result
can lessen bias.
ReplicationThe experiment must be repeatable.
A scientific theory is an explanation of things or events based on knowledge gained from many observations and investigations.If scientists repeat an investigation and the results always
support the hypothesis, the hypothesis c an be called a theory.
Scientific law is a statement about what happens in nature and seems to be true all the time.Example: gravity—no experiments have been performed
to disprove this accepted law of gravity
Limitations of ScienceTechnology is the application of science to
help others
It is not always possible to do an experiment to test a hypothesis:Ethical issues of humans
Ex: Does this chemical cause cancer in humans?Disruption of a natural system
Ex: How do animals in the wild interact with each other?
Scientific Method ActivityStudents will work with lab groups to
understand the scientific method. Each group must:
Ask a questionForm a hypothesisDesign an experiment
Including all variables that would be testedCreate fictional data that accepts or rejects the
hypothesisDraw conclusion
Standards of Measurements A standard is an exact quantity that people
agree to use to compare measurements
For a measurement to make sense, a number and unit must be present.
International System of Units: in 1960s all scientists agreed upon an updated metric system; it is abbreviated SI
SI Base Units
Quantity Measured
Unit Symbol Used
Length meter m
Mass kilogram Kg
Time Second s
Electric current ampere A
Temperature kelvin K
Amount of substance
mole mol
Intensity of light candela Cd
Prefix
Symbol
Multiplying Factor
Kilo- k 1,000
Deci- d .1
Centi-
c .01
Milli- m 0.001
Micro-
µ 0.000 001
Nano-
n 0.000 000 001
Measuring DistanceLength is the distance from one point to
another
What can we use to measure length in the lab?
Common SI Units (meter = slightly longer than a yard)1 meter (m) = 100 centimeters (cm)1 meter = 1000 millimeters (mm)1000 meters = 1 kilometer (km)
Measuring MatterThe amount of matter in an object is defined
as mass.
How could we measure mass in lab?
Common SI Units (1 gram = 1 paperclip)1 kilogram (kg) = 1000 grams (g)1 gram = 1000 milligrams (mg)1000 kilograms = 1 metric ton (t)
Finding VolumeVolume is the amount of space an object takes
up.
How is volume measured?
Common SI Units1 liter (L) = 1000 milliliters (mL)1 liter = 1000 cubic centimeters (cm3)
Density is the mass per unit volume of materialMass (g)/ Volume (cm3)
TemperatureTemperature is used to measure hotness or
coldness.
How is temperature measured?
Common SI Units (Kelvin)Add 273 to the °C to determine K0°C = freezing point of water100°C = boiling point of water
Common English-Metric Conversions 2.54 centimeters (cm) = 1 inch (in.)
1 meter (m) = 39.37 inches (in.)
1 kilometer (km) = 0.62 miles (mi)
1 liter (L) = 1.06 quarts (qt)
236 milliliters (mL) = 1 cup (c)
1 kilogram (kg) = 2.2 pounds (lb)
28.3 grams (g) = 1 ounce (oz)
°C = 5/9 x (°F – 32)