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UNIT ONE: Habits of Mind. How scientists work. No matter what types of problems are being studied, scientists use the same problem-solving steps called the scientific method . The scientific method is A logical and systematic approach or process to problem-solving. - PowerPoint PPT Presentation
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UNIT ONE:HABITS OF
MIND
No matter what types of problems are being studied, scientists use the same problem-solving steps called the scientific method.
The scientific method isA logical and systematic approach or process to problem-solving.
An organized way of using evidence to learn about the natural world.
HOW SCIENTISTS WORK
1. Make an observation.2. Define the problem.3. Research the problem.4. State the hypothesis.5. Experiment to test the hypothesis.6. Collect and record data.7. Analyze the data.8. Draw conclusions.9. Report results.
LISTING THE STEPS
Then
And
Question
Research
Hypothesis
Procedure/Method
Data
Observations
Conclusion
What does the scientist wantto learn more about?
Gathering of information
An “Educated” guess of ananswer to the question
Written and carefullyfollowed step-by-step
experiment designed to testthe hypothesis
Information collected duringthe experiment
Written description of whatwas noticed during the
experiment
Was the hypothesis correct or incorrect?
Next
Then
Next
And
Finally
FirstScientific MethodAn Overview
Question: What will happen to the magnesium metal if I drop hydrochloric
acid into the test tube?
SCIENTIFIC METHOD
Ask Question
Do BackgroundResearch
ConstructHypothesis
Test with anExperiment
Analyze ResultsDraw Conclusion
Think!Try Again
Report Results
Hypothesis is True Hypothesis is Falseor Partially True
Aristotle proposed that living things can be generated from non-living things, and his theory is called Spontaneous Generation in 322 BC.
People accepted the idea.Francesco Redi disagreed in 1668. He
was trying to disprove the idea of Spontaneous Generation using fruit flies.
WAIT…people believed this for 1668 + 322 years!
REDI’S EXPERIMENT ON SPONTANEOUS GENERATION
Maggots occur on meat after a few days.
MAKE AN OBSERVATION
How did the maggots get on the meat?
DEFINE THE PROBLEM.
Redi observed that maggots appeared on the meat after a few days.
He believed that flies landed on the meat, laid eggs, and the eggs hatched.
RESEARCH THE PROBLEM.
Flies produce maggots.
STATE THE HYPOTHESIS
Redi set up a controlled experiment. Others have used his experiment as a model for setting up their own experiments for many years.
EXPERIMENT TO TEST THE HYPOTHESIS
Control GroupExperimental
Group
Control Group: used as a standard of comparison Jars with meat and
no coverControl variables:
same jars, same type of meat, same location, same temperature, same amount of time (MANY)
Experimental group: Jars with meat and a gauze cover
Manipulated variable: gauze covering the jar (ONLY ONE)
Dependent variable: whether maggots appear or not (RESULT)
IMPORTANT VOCABULARY & CONCEPTS
Redi recorded the size jar, type of meat, amount of meat, location of meat, temperature of room, time passed, type of gauze used, changes in meat each day, and when/if maggots appeared.
Maggots only appeared on the meat in the uncovered jars after a few days. No maggots appeared on the meat in the covered jars.
Types of Data: Quantitative: involves numbers; often graphedQualitative: does not involve numbers
COLLECT DATA
Redi reviewed his hypothesis: Flies produce maggots.He accepted the hypothesis because of the data.Flies must have laid eggs that are too small to be seen.
Flies could not get to the covered meat to lay their eggs.
Maggots did not spontaneously generate on the meat.
EVIDENCE was necessary to disprove Aristotle’s claim. Data IS evidence.
DRAW CONCLUSIONS
Redi looked over his work carefully. He tried to identify mistakes in his experiment. Could there be another explanation for his results?
He looked for ways to improve his experiment.
He decided if it was necessary to repeat the experiment with the improvements.
DETERMINE LIMITATIONS
When Redi was satisfied with his results, he wrote a report of the experiment outlining all of the information that we’ve discussed.
He published that report in 1668 in a book.
Other scientists repeated his experiment to check his work, and finally the theory of spontaneous generation was disproved.
REPORT RESULTS
Variables - Factors that can be changedControlled Variables - all the variables that remain constant
Independent Variable - (also called the Manipulated Variable) - factor in an experiment that a scientist purposely changes
Dependent Variable- (also called the Responding Variable) - the outcome or results, factor in an experiment that may change because of the manipulated variable….what a scientist wants to measure or observe
Graphing Rule: Graph the dependent variable on the Y-axis. The independent variable goes on the X-axis.
REVIEW OF EXPERIMENTAL VARIABLE VOCABULARY
OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat.
HYPOTHESIS: Flies produce maggots.
PROCEDURE
Manipulated Variables:gauze covering thatkeeps flies away from meat
Uncovered jars Covered jars
Several days pass
Maggots appear No maggots appear
Responding Variable: whether maggots appear
CONCLUSION: Maggots form only when flies come in contact with meat. Spontaneous generation of maggots did not occur.
Controlled Variables:jars, type of meat,location, temperature,time
Usually quantitative data is measured with an instrument in the lab.
Scientists use the metric system units.
GATHERING QUANTITATIVE DATA
Measurement Equipment Used Metric Base UnitLength Metric ruler or meter
stickMeters
Mass Balance GramVolume of a liquid Graduated cylinder Liter
Time Stopwatch or second hand on clock
second
The metric system is based upon powers of ten. Prefixes are added to the base units to make larger or
smaller units. Example: milli, kilo, or deci
Since our number system is also based on powers of ten, converting from one metric prefix to another is as simple as moving a decimal.
Memory device: King Henry died by drinking chocolate milk.
METRIC SYSTEM PREFIXES & CONVERSIONS
Kilo Hecto
Deca BASE Deci Centi Milli
K h D MeterLiterGram
d c m
1000 100 10 1 .1 .01 .001
Conversion examples Convert 145.8 cm to mm.
1458 mm Convert 3.4 kg to dg.
34,000 dg Convert 13,499 mL to hL.
0.13499 hLFor homework tonight, complete the metric mania
worksheet.
METRIC SYSTEM PREFIXES & CONVERSIONS
Kilo Hecto
Deca BASE Deci Centi Milli
K h D MeterLiterGram
d c m
103 102 101 1 10-1 10-2 10-3
Biology is the study of life!Are Flames Alive?All living things have 8 characteristics in
common.1. Made of one or more cells2. Displays organization3. Grows & develops (increase in mass & gains new
abilities)4. Reproduces5. Responds to stimuli (ex. heat, light, weather)6. Requires energy7. Maintains homeostasis (stable internal conditions)8. Adaptations evolve over time (help species
survive)
CHARACTERISTICS OF LIVING THINGS
Levels of OrganizationOrganismsOrgan systemsOrgansTissuesCellsMoleculesAtoms
DISPLAYS ORGANIZATION