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)

Metric/SI Measurement LabUsing the knowledge we learned today,

complete the worksheet using lab materials supplied at your table.

Who has bigger hands: practice with the scientific method