Monday, March 1, 2010

Helping students to design experiments

A student might be interested in an article from the newspaper or a digitized article like this one: That interest in the news or digital article can be steered into an excitement for science.

The example states:

... a recent study revealed that combining blueberries and milk in the same meal could block your body's absorption of the antioxidant goodness in the berries.

The example also posts the original source:
Published on 03/01/2010
Antioxidant activity of blueberry fruit is impaired by association with milk. Serafini, M. et al., Free Radical Biology & Medicine 2009 Mar 15;46(6):769-774.

[Note: Not all articles post the original source (though ethics says they should), but, you can use Reach Reading TM skills to help a student find original sources on the same material.]

Now, the student might come in bursting with questions...
What if I eat my blueberries with cream, yogurt, or cheese? What about raspberries? Does milk affect the absorption of antioxidents from raspberries?
If the student doesn't have such questions, but, is interested in the article, you might steer him or her to formulate such questions.

Such curiosity is the beginning of experimental design when one thinks like a scientist. What is the next step?


If you said formulate a hypothesis, or something similar. That's good. But suppose the student said, "Let's have a yogurt (or, even better...blueberries) snack," as long as you took the snack out of the lab, or washed the whole lab and everyone washed his or her hands, too (safety first), could come under the guise of preliminary research. Hmm! Remember, science is supposed to be fun (or we'd have no scientists...). Also, eating the yogurt will give time for discussion, and other students might come up with other hypotheses.
I want to test carrots?
Is this why my parents say, "don't eat spinach and milk at the same time?"
and other questions---soon to be hypotheses. Can you feel the excitement catching on? Students might not have thought about chemicals in their foods before (Oh, yes, all matter is made of atoms...Here is a, "teachable moment:" not all chemicals are bad.)

More coming....

Other students might branch out and get ideas for experimental design on health and beauty issues, for example, this link: Skin Care Information, Research and Reviews. Look at all the chemistry he or she could get in just a couple of clicks (Don't forget, biologists (from botanists to cell biologists , skin biologists to ...) use a lot of chemistry, and for that matter, physics):
Hyaluronic acid is synthesized by the enzymes called hyaluronan synthases. Humans have at least three types of hyaluronic acid synthases: HAS1, HAS2, and HAS3. HAS1 and HAS2 synthases produce high molecular weight HA whereas HAS3 produces low molecular weight HA. Hyaluronic acid is degraded by the enzymes called hyaluronidases, of which there also appear to be several types

Source:; Accessed 2-29-2010.

What is the end result the student would expect from a design?




Did you say:
Gather background information and write it up?
Form a hypothesis?
Create a protocol...what you will do (steps)...what will you use?
Create a table for collecting the data you expect to collect?
Keep track of sources you used?
or, something like that?

Okay so, how do they get there?

You can throw out the open-ended question of how much it would cost to do the experiment they have designed. Remind students of funding and the tax-connection. Is the experiment worth doing? Why or why not? Is the design sound? Is there a control planned? Has a thorough literature search been done? Do we already know the answer?

Ah! That last question is very important for funding,
Do we already know the answer?

Another important concept to convey is,

What if we get the opposite of what our hypothesis predicted, do we fail the experiment?

This question, too, is important for funding.

Can you think how?





Here's a blueberries video while you think:

; Accessed March, 1, 2010.

(c) 2010 J S Shipman. All rights reserved.

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