Notes Scientific Method How Scientists Work

How Scientists Work: Solving the Problems Much of science deals with solving problems These problems can be environmental, economic, health related, etc. No matter what types of problems are being studied, scientists use the same problem-solving steps called… The Scientific Method

Scientific Method Definition The scientific method is- A logical and systematic approach to problem solving.  An organized way of using evidence to learn about the natural world http://images.google.com/imgres?imgurl=http://web.syr.edu/~ksegrave/Courses_pages/FieldBiology/FieldBioImages/method.gif&imgrefurl=http://web.syr.edu/~ksegrave/Courses_pages/FieldBiology/Science.html&h=175&w=225&sz=17&hl=en&start=11&um=1&tbnid=wdFWEsauzWqdBM:&tbnh=84&tbnw=108&prev=/images%3Fq%3Dscientific%2Bmethod%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN http://en.wikipedia.org/wiki/Scientific_method

Scientific Method Listing the Steps Make an Observation Define the Problem/Question Research the Problem State the Hypothesis Develop Experiment-it’s a test! Perform experiment Collect and Record Data Analyze Data Communicate the Data-graph Draw Conclusions Determine Limitations Report Results If needed, Do more investigation

1. Observing Make an observation Use senses to notice As we all know, frogs have four legs. Make an observation Use senses to notice something unusual that makes you CURIOUS! What’s up with these froggies? http://www.science.psu.edu/alert/Images/Kiesecker7_-02images/Deformed_frog_assorted_RASY.jpg

2. Questioning Recognize, state or define the problem Must be in the form of a question MUST BE TESTABLE http://images.google.com/imgres?imgurl=http://news.minnesota.publicradio.org/features/2005/10/21_bensonl_research/images/truncfemur_large.jpg&imgrefurl=http://news.minnesota.publicradio.org/features/2005/10/21_bensonl_research/&h=225&w=300&sz=9&hl=en&start=7&um=1&tbnid=lA9c0bTzPYtApM:&tbnh=87&tbnw=116&prev=/images%3Fq%3Dfrog%2Bdeformities%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN http://academic.brooklyn.cuny.edu/geology/leveson/core/graphics/nyc_mins2/qmarks.gif http://www.kidcrosswords.com/animated_dictionary/d_e_f/frog.gif

3. Researching Gather information related to the problem Read and study what has already been reported on this topic. Someone may have already answered your question http://www.okc.cc.ok.us/biologylabs/Images/Scientific_method_images/frog.jpg

4. Hypothesizing A hypothesis is: A prediction or possible explanation Must be an “If, then…” statement, which will include your independent variable and dependent variable Must be testable Is based on your research and previous experience http://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.html#The%20obvious%20question http://www.science.psu.edu/alert/Images/Kiesecker7_-02images/Deformed_frog_assorted_RASY.jpg

Variables in an Experiment Variables - Factors that can change in an experiment Controlled Variables - all the variables that a researcher keeps constant Independent (Manipulated) Variable- factor in an experiment that a scientist purposely changes Dependent (Responding) Variable - factor in an experiment that may change because of the independent variable

5. Experimenting Goal of an experiment is to test the hypothesis You must perform your experiment many times to gather evidence (at least 3 times) http://info.hartwick.edu/biology/def_frogs/Introduction/Exploration/explore.html#The%20obvious%20question http://www.tmbfree.com/images/graphics/clipart/froggy2.gif http://images.google.com/imgres?imgurl=http://www.frogcollecting.com/gallery/A2t.gif&imgrefurl=http://www.frogcollecting.com/gallery/gallery.html&h=97&w=80&sz=1&hl=en&start=8&um=1&tbnid=hR-tjkzZyAWtTM:&tbnh=81&tbnw=67&prev=/images%3Fq%3Danimated%2Bjumping%2Bfrog%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN

Setting up a Controlled Experiment In a controlled experiment, only one factor is changed at a time. Independent variable: the factor that is deliberately changed Dependent variable: the factor that the scientist wants to observe; it changes in response to the independent variable

Control and Experimental Groups Control Group- used as a standard for comparing. This group is left alone- or “under normal conditions” Experimental Group-the group containing the factor that has been changed. This group receives the independent variable.

What do I do next??? The steps a researcher will follow to test their hypothesis is their PROCEDURE: Must be a numbered list of directions Must include all the variables: independent, dependent and controlled/constants. The more controlled variables, the more VALID the results are They MUST know what they are going to measure (DEPENDENT) and how

Measure??? Must use the correct tool for measuring-thermometer, triple beam balance, graduated cylinder, ruler, stop watch Must know what you are measuring: time, mass, volume, temperature Keep track of all of your data in a TABLE

6. Collect and Record Data Data: Observations and measurements made in an experiment Quantitative - observations that involve measurements or numbers; i.e. 3 days, 12 maggots, 4 g, 13 sec, 8 liters Qualitative - observations that do not involve numbers, are of a descriptive nature i.e. rabbits fur color changed, leaves were all wilting http://images.google.com/imgres?imgurl=http://www1.istockphoto.com/file_thumbview_approve/310758/2/istockphoto_310758_the_mad_scientist.jpg&imgrefurl=http://www.istockphoto.com/file_closeup/%3Fid%3D310758%26refnum%3D361997%26Lang%3Den&h=367&w=380&sz=49&hl=en&start=27&um=1&tbnid=vejiM3E-VcJ5JM:&tbnh=119&tbnw=123&prev=/images%3Fq%3Dscientist%26start%3D20%26ndsp%3D20%26svnum%3D10%26um%3D1%26hl%3Den%26sa%3DN

7)Communicate Data All data must be put into a GRAPH. The type of graph you use must reflect the data: Line graph- Shows changes as time is going by Bar graph- Comparing things that aren’t related Pie graph- Percents

8. Analyze the Data Examine data tables, charts, and graphs Examine experimental notes Look for trends, patterns, and averages What does the data show Put your data into words

9. Draw Conclusions Accept or reject the hypothesis, based on your experimental results. If accepted, support your conclusion with specific, numerical data. If rejected, explain why & go back to the drawing board- either change your experiment or change your hypothesis

10. Determine Limitations Scientists look for possible flaws in their research They look for faulty (inaccurate) data They look for experimental error or bias's They decide on the validity of their results They make suggestions for improvement or raise new questions

11. Publish Results Communication is an essential part of science Scientists report their results in journals, on the Internet, or at conferences This allows their experiments to be evaluated and repeated Scientists can build on previous work of other scientists

Can you put these steps in order? Define the Problem 2 Analyze Data 7 10 8 6 Report Results Make an Observation State the Hypothesis 5 1 4 the Problem 9 3 http://images.google.com/imgres?imgurl=http://www.abcteacher.com/images/cwg3503.gif&imgrefurl=http://www.abcteacher.com/catalog/pages/cwg3503.shtml&h=283&w=295&sz=51&hl=en&start=14&um=1&tbnid=LNucRj8DmvEUbM:&tbnh=110&tbnw=115&prev=/images%3Fq%3Dscientific%2Bmethod%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN Determine Limitations

Steps of Scientific Method in order 1 State the Hypothesis Make an Observation Define the Problem 2 the Problem 3 4 5 6 Analyze Data 7 8 http://images.google.com/imgres?imgurl=http://www.abcteacher.com/images/cwg3503.gif&imgrefurl=http://www.abcteacher.com/catalog/pages/cwg3503.shtml&h=283&w=295&sz=51&hl=en&start=14&um=1&tbnid=LNucRj8DmvEUbM:&tbnh=110&tbnw=115&prev=/images%3Fq%3Dscientific%2Bmethod%26svnum%3D10%26um%3D1%26hl%3Den%26rls%3DGGLB,GGLB:1969-53,GGLB:en%26sa%3DN 9 10 Report Results Determine Limitations

Scientific Theory A theory is an explanation of a set of related observations or events based upon proven hypotheses and verified multiple times by detached groups of researchers http://www.antiquark.com/img/scientific_method.jpg http://wilstar.com/theories.htm

Scientific Law Scientific Method Scientific laws represent the cornerstone of scientific discovery They must be simple, true, universal, and absolute If a law ever did not apply, then all science based upon that law would collapse http://www.debunking911.com/hypothesis.gif http://wilstar.com/theories.htm

Science at Work Let’s look at an example of the Scientific Method using Francesco Redi’s Experiment on Spontaneous Generation He was trying to disprove the idea of Spontaneous Generation http://hometown.aol.com/ksmith9526/braininjar.gif Francesco Redi (1668)

Stating the Problem Example: How do new living things come into being? Spontaneous generation once commonly accepted Redi wanted to show what caused the appearance of maggots (and then flies) on meat

Belief based on prior observations If leaf lands on water it becomes a fish If a bale of hay is left in barn, it produces mice Muddy soil gives rise to frogs Meat hung out in the market is the source of flies

Forming a Hypothesis Redi’s Hypothesis: Flies produce maggots. How could he test this? Through a controlled experiment http://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Don_francisco_de_quevedo-villegas.jpg/120px-Don_francisco_de_quevedo-villegas.jpg http://www.ifir.edu.ar/~divulgon/diciembre04/imagenes/redi.jpg

Redi’s Controlled Experiment Redi used two groups of jars Jars that contained meat and no cover Jars that contained meat and gauze cover Jars with meat Uncovered jars http://hometown.aol.com/ksmith9526/braininjar.gif Covered jars

Variables in Redi’s Experiment Controlled Variables: jars, type of meat, location, temperature, time Manipulated Variables: gauze covering that keeps flies away from meat

Let’s think about this.… Which is the control group? Which is the experimental group? Uncovered jars Covered jars Two groups of Jars with meat Uncovered jars Covered jars

Redi’s Experiment on Spontaneous Generation OBSERVATIONS: Flies land on meat that is left uncovered. Later, maggots appear on the meat. HYPOTHESIS: Flies produce maggots. PROCEDURE Manipulated Variables: gauze covering that keeps 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