Remote Ready Biology Learning Activities
Remote Ready Biology Learning Activities has 50 remote-ready activities, which work for either your classroom or remote teaching.
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Disassembling The Scientific Method
The following is from an NSTA exchange among educators:
Hypothesis
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Rob0bops@aol.com
to generalscience, environmentals., physics, chemistry, physicalscienceMATTHEW WELLS
to Rob0bops, chemistry, environmentals., generalscience, physicalscience, physicsGreat topic.
I wish we could stop using the phrase "scientific method"!
There are many types of legitimate scientific investigation, and not all of them require the isolation of variables, or the stating of hypotheses (is that the plural?).
"Descriptive" investigations are as their name suggests, and don't necessarily require a formal hypothesis.
"Comparative" investigations may investigate relationships between variables, and require some kind of null hypothesis (although not necessarily a "control group")
"Experimental" investigations are the more typical, traditional type that we used to call "the scientific method", where a hypothesis is essential to the design of the experiment.
When it comes to hypotheses, I always keep it simple with the following definition:
"A hypothesis is a scientifically testable statement"
I have found that this "catch-all" definition allows for a wide variety of legitimate expressions.
Matt Wells
Science Dept. Chair
http://mattwells.wikispaces.com
Cypress Lakes HS
5750 Greenhouse
Katy TX 77449
Cell: (281) 799-0542
>>> <Rob0bops@aol.com> 9/10/2010 1:48 PM >>>
Along the way, hypothesis came into the discussion. The responses have been
very enlightening and sometimes contradictory. I would like to open this
subject up to more discussion on this listserv if you would care to
commment (for those of you who subscribe to multiple lists, I apologize).
What exactly is a hypothesis?
Should scientific inquiries always have one stated?
Should the hypothesis be stated in an "If.. then..." statement?
Should a hypothesis include a "because".... as well?
How do we get away from implying causation or when should it be implied?
If anyone has further questions on this or can phrase these in a better
way, please go ahead.
I teach at a school for K-8. I would really like to have our students
have a good concept of scientific inquiry that will carry them beyond our
school into their further learning.
I would also like to take this opportunity to thank each and everyone of
you who reply to these. Your comments and suggestions have been invaluable to
me - within days of reading them, I am applying them in my classroom. On
behalf of myself and my students, I send you a very heartfelt thank you.
Robin Wooten
Holy Trinity School
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Don Abel
to Rob0bops, MATTHEW, chemistry, environmentals., generalscience, physicalscience, physicsyep, I agree with matt and we should also get rid of the generalization about PHEOC as the scientific method. PHEOC to me is how you complete a lab write up and not how you do science. KUDOS.
Don Abel, Jr.
7th Grade Life Science Teacher
D.C. Everest Middle School
9302 Schofield Ave.
Schofield, WI 54476
715-214-9700 Ext. 2222
>>> "MATTHEW WELLS" <MATTHEW.WELLS@cfisd.net> 9/10/2010 2:03 PM >>>
Great topic.
I wish we could stop using the phrase "scientific method"!
There are many types of legitimate scientific investigation, and not all of them require the isolation of variables, or the stating of hypotheses (is that the plural?).
"Descriptive" investigations are as their name suggests, and don't necessarily require a formal hypothesis.
"Comparative" investigations may investigate relationships between variables, and require some kind of null hypothesis (although not necessarily a "control group")
"Experimental" investigations are the more typical, traditional type that we used to call "the scientific method", where a hypothesis is essential to the design of the experiment.
When it comes to hypotheses, I always keep it simple with the following definition:
"A hypothesis is a scientifically testable statement"
I have found that this "catch-all" definition allows for a wide variety of legitimate expressions.
Matt Wells
Science Dept. Chair
http://mattwells.wikispaces.com
Cypress Lakes HS
5750 Greenhouse
Katy TX 77449
Cell: (281) 799-0542
>>> <Rob0bops@aol.com> 9/10/2010 1:48 PM >>>
On the biology listserv, the subject of "scientific method" was discussed.
Along the way, hypothesis came into the discussion. The responses have been
very enlightening and sometimes contradictory. I would like to open this
subject up to more discussion on this listserv if you would care to
commment (for those of you who subscribe to multiple lists, I apologize).
What exactly is a hypothesis?
Should scientific inquiries always have one stated?
Should the hypothesis be stated in an "If.. then..." statement?
Should a hypothesis include a "because".... as well?
How do we get away from implying causation or when should it be implied?
If anyone has further questions on this or can phrase these in a better
way, please go ahead.
I teach at a school for K-8. I would really like to have our students
have a good concept of scientific inquiry that will carry them beyond our
school into their further learning.
I would also like to take this opportunity to thank each and everyone of
you who reply to these. Your comments and suggestions have been invaluable to
me - within days of reading them, I am applying them in my classroom. On
behalf of myself and my students, I send you a very heartfelt thank you.
Robin Wooten
Holy Trinity School
To change your listserv settings or to unsubscribe,
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David Smith
to Rob0bops, generalscience, environmentals., physics, chemistry, physicalscienceHypotheses are perhaps the most misunderstood part of science in K-12 science teaching. A hypothesis is, at its essence, an explanatory statement. It is NOT an "educated guess" or a guess of any kind, although this is what it often becomes when teachers ask students without sufficient depth of knowledge to formulate a hypothesis. It is also distinct from predictions, which are a statement of what will happen if certain conditions are met.
"Table salt will melt ice faster than sugar" is a guess, not a hypothesis, because there is no explanation. "I know that adding a soluble material to water causes freezing point depression, so sugar, table salt, and epsom salt should all melt ice at -5 C" is a hypothesis because it offers a mechanism to explain the expected results. It may be an incorrect explanation, but hypotheses are necessarily tentatively held and subject to refutation.
The hypothesis is only a required part of an investigation in school books. Plenty of science inquiry can be conducted, and often needs to be conducted in the absence of a hypothesis. Hypotheses, because they are explanatory, require a lot of information before they can be formulated. That information comes from investigations that are not hypothesis-driven. Most school labs are not hypothesis driven either, which is why, when students are asked to write hypotheses, they produce such bad ones and they fail to learn what a hypothesis really is. Take the distillation of wood lab that I did at the beginning of high school chemistry some decades ago - in order to offer a reasonable hypothesis for the origin of the methanol we produced, I would have had to know a great deal of organic/biochemistry. It's not that one couldn't offer a reasonably formulated hypothesis for the conditions under which thermal decomposition of cellulose would yield methanol, but that we, as beginning students, did not have nearly enough knowledge to do so.
Requiring if...then... statements is problematic. Some hypotheses may take this form, but I could write hypotheses all day that are not if...then... or even if..then..because... statements. If... then.. format also leads to confusion with predictions, which very often take an if... then... form. Students should learn to write and understand a diversity of forms and creativity of expression should never be inhibited provided the statement remains a hypothesis. That said, it may be helpful to offer a struggling student a form as a scaffold (but far too often, we give students a scaffold before they need one, just because someone last year needed it and it would be so much more efficient just to give it to them - efficient, yes, effective, no). Here is a possible scaffold:
I know that _(independent variable)_ affects __(dependent variable)__ by _(action)_ (cite background research). Therefore, when __(experimental condition)__, the __(dependent variable)__ will __(change expected)__ when compared to the __(control condition)__.
For example (with thanks to Robert Krampf, from who I got this example), I might write:
I know that enzymes affect proteins by breaking them down (research cited). Therefore, when protein based stains are washed in an enzyme-containing detergent, the stain will be removed more thoroughly when compared to the same stains washed in a non-enzyme detergent.
I could write it more felicitously if I weren't trying to stay in the form, but it will give students a guide.
Hypotheses can and often do imply a causal link - the enzymes in the detergent break down the material of the stain causing it to be more effective. The danger comes in making the same leap in the interpretation. A positive result TENDS TO SUPPORT your hypothesis, it does not prove it! Hypotheses can never actually be proven true. They can however be proven false. This is hard for students to understand, in part because they are surrounded by teaching and materials that present scientific understandings as Truth, and in part because it is simply a challenging idea that something can be well-known without being known for sure.
There's a great resource for all of this called Understanding Science at
http://undsci.berkeley.edu/
Their descriptions of the process and methods of science are as accurate as anything i have ever read.
Dave Smith, long-time scientist, turned professional developer