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"Ideas and Evidence" topic

TwoShanks

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I'm a (fairly new) science teacher in the UK and I've now been asked to write a scheme of work for Year 9 entitled "Ideas and Evidence", which is intended to be a sort of "How Science Works" module (see http://www.standards.dfes.gov.uk/schemes2/secondary_science/sci09m/?view=get) - i.e. teaching the scientific method.

I thought this might be a good place to get some interesting critical thinking work involved, including experiments, while still meeting the curriculum needs.

I've made a start - the first lesson involves deciding the sort of question that can be answered scientifically and planning an experiment accordingly - but I'd like any advice or comments on how to proceed, bearing in mind that it will need to be differentiated for levels 3-8 inclusive. Topic should last about 8 lessons in total, so I have plenty of time for experiments.

Any suggestions will be gladly received.
 
Ah, Year 9 is the third year of secondary school (i.e. 13-14 years old).
Levels 3-8 represent the ability of the students, where 8 is the highest possible ability and 3 is well below the average expected of 11 year olds. Basically a very large range of ability.
 
I think there are two ways to go, maybe you could do both.

1st) You could demonstrate a real scientific phenomenon, Then ask for ideas as to why they think it happens, then set a class exercise to try and come up with tests to see if that is the case.

2nd) You could demonstrate a phenomenon like the ideomotor effect ask for tests to see if its real and then reveal the truth demonstrating the need for double blind studies.

Problems:
1) I haven't thought of a good phenomenon for number 1 yet Still thinking, It has to be one that there could be lots of explanations for, but whose mechanisms are still easily guessed at and tested for. The only one I can think of right now is when our physics teacher put a metal rod in a flame and it started to droop. "Melting" we all said, then he flipped it over and it continued to curl up. It was really a bimetallic strip. Good luck with finding a good example!

2) There may be more than the ideomotor effect going on. Some of the students might just want to please the teacher by deliberately making a dousing rod twitch. Also you have to make dousing rods.
 
Introducing Probability

One of the key ideas of science is that we live in a probabilistic universe -- thus no phenomenon will occur 100% of the time, nor 0% of the time. For students at this age, who tend to be impulsive and binary in their view of the world, you could be very helpful in their growth by introducing the idea that everything which guides decisions is really based on probability.

To do this, in a fun and challenging way, you might look at the work that has been done in Games Theory. Games such as "Prisoner's Dilemma," "Chicken," and several others can provide both challenge and incorporation of this kind of world view.

Search for the "Chicken Game" in Wikipedia, or "Prisoner's Dilemma" to see the many ways these games can be administered.

Assuming you know students fairly well, pair those who tend to be high risk takers, and have the rest of the class engage in predictions of who will come out the winner. here are infinite variations for scoring, and pairing of combatants.

You can also up the ante by having rewards (such as no homework for the winners, or those who make best predictions) and even some punishment (extra homework, reduction in grade average) for losers.

Years ago, when I was a middle school teacher of Social Studies (History, Government), I used this tool to great advantage in helping students to incorporate this concept into their thinking.
 
I'm sure that there are others on the forum who could direct you to existing lesson plans for Critical Thinking. That might save a lot of time.

For myself, here's a suggestion for a module on Expectation Bias:



I'd suggest reproducing the N-ray experiment in small groups. You could use grade 12 physics lasers instead of x-rays, and black metallic blocks as prisms. The prisms should be housed in a cardboard box of some kind, so as to be hidden from the operator's view.

First, have the groups record the positional angle of N-rays in their apparatus, under the assumption that they're real. This is the way most highschool 'experiments' work, unfortunately: confirmation.

Second, propose that there may not *actually* be N-rays. Let the groups devise their own experiments to determine this.

Lastly, explain that actually, N-rays are not real, but greater minds than your students have been fooled, and now we know proper ways to conduct experiments to remove expectation bias. Hopefully, one of the groups will have tripped over the double-blinded technique of adding/removing the prism without telling the operator.
 
Oh, another expectation bias would be to reproduce Cox' braincase capacity studies. Give different groups identical containers, but tell them they have different volumes. Then, allow them to measure the volumes with, say, mustard seeds or something compressible. You will find that the groups' results will cluster around the 'known' volumes.

And it's not just Cox: the value of the electron charge went through a slow migration from Millikin's value to the real value because of exactly this bias.
 
For the higher-level students, one approach might be to take some area in the sciences that has yet to be explained, but competing theories exist, and examine why each theory exists, what the areas of controversy are, and what tests are being done to arrive at a better understanding of the pheonomenon. It might need to be simplified to be age-approprite.

Another idea would be to examine missteps in science, and how they were eventually corrected (to the degree we can truly know they were "corrected", give the provisional nature of science). Paradigm shifts in physics offer plenty of examples. For a more recent example, examining how the cold fusion hoax of 1989 unfolded might be instructive.
 
When I was in school I had a class similar to this, "how science works," "what is a scientific question," etc. Coincidentally that's where I first heard about James Randi.

One thing I remember my teacher doing was demonstrating false claims like psychics, magic tricks, etc, and showing how these things violate the rules of scientific investigation. He made us think critically about these topics and try to design experiments to test out phenomena like that.

A class like this should be taught to all high school students. I think scientific methodology is more important than any one of chemistry, biology, or physics.
 
I think another recent example of experimental biase is in gene therapy studies. Especially in the cases of the Magical TAT sequence.

It went from making anything cell membrane permable to directly targeting the nucleus to simply being a charged based internalization and cellular trafficking event.
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But all of this raises a critical aspect of the scientific method. Peer review.


Perhaps have a section where students conduct an experiment and have a seperate group evaluate and critique their findings.

you could do this with your N-ray experiment by just telling the one group conducting the experiment of thier existance. Then tell the evaluting group nothing of them, but that they may or may not exist.
 
Looking at some of the suggestions, it seems to me that many have a problem in that they rquire a level of content knowledge that many students at the age you specify are unlikely to have.

With that in mind, let me add a low-cost (if at al) easy to conceptualize question you can readily use:

Filll two glasses with tap water -- one nearly full, the other half full. insert a thermometer in each. Put both glasses in a refrigerator until frozen solid. Test the hypothesis: There will be no significant difference in the time needed to raise both glasses to room temperature. Have your students make predictions about the time needed, and then measure actual time for each glass.

Using the predictions for Glass 1, and Glass 2, you can also get in to the differences in prediction compared with actual times.
 
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