Creating the student-centered lab

[fishspawned]

I had mentioned in another thread that I had just started teaching Physics.

I had spoken about the qualities of a Physics teacher and the challenges he/she may face but something I left out was "The Lab". This was something that was a thorn in my side right from the start going back to when I was in high school ( the 80s!). And I was hoping that I could start a thread where other teachers would be interested in contributing their ideas as well.

My experience of Labs, including the ones proposed to me by other Physics teachers have been of a the standard format.
1. A set of instructions
2. The student follows these instructions to get the expected result
3. The student writes a lab report [usually cutting/pasting the procedure into it]

In my opinion, this does not allow a student to make use of scientific inquiry but instead learn how to be a good worker. So I took it upon myself to recreate the labs (which I'm sure many of you have done as well) so that they became centered upon a more student centered approach.

When we were to do the lab regarding gravity and basic motion laws, my lab was the simplest. The conversation was as follows:

T: "what is the value acceleration due to gravity?"
S: "9.8 m/s^2"
T: "Great. prove it."

And that was the lab. I offered little more than guidance following this. What this does is provide several opportunities:

1. Students must develop their own experiment
2. Students will learn that failure is a part of the process
   
3. Students will be forced to realize the importance of both Accuracy and Precision [such as the need for Trials) within their experiments.
4. Procedures will have a value within the lab [i should note that I also insisted that they submit the Procedure to their experiment BEFORE they did it - this I found to be very important]

The experiment was incredibly successful. They were, at first, completely freaked out being left in the ocean without a paddle. But it took no time at all for them to start to critically think about what they knew in order to come up with a very wide variety of experimental procedures.

Another experiment. Two blocks of wood [the ability to add extra weight is there] are provided and students are asked to produce a race between them [on an inclined plane] where one beats the other by 2 seconds exactly. An experiment focusing on friction.

I am sorry for the length of this post but here I stop and simply ask if anyone else has managed to put together similar open ended experiments. I thought this would be a great place to share.

 

[ZapperZ]

You might be interested in an old thread that I created that tried to highlight my own "pet project" at revamping Undergraduate Intro Physics Lab. These have open ended experiments where all they are doing will be discovering correlations (if any) between two quantities, and studying a cause-and-effect. There's even one that challenges them to come up with their own explanation based on what they already know and perceive from their everyday experiences.

https://www.physicsforums.com/threa...duate-introductory-physics-laboratory.271833/

I think that the experiments I suggested are simple enough that they can even be done at the high school level. It was certainly targeted to non-science majors who do not get a lot of opportunities to perform experiments.

Zz.

 

[fishspawned]

ZapperZ,

An excellent resource!
Thanks for the link. I will be spending some time there.

 

[Birkeland]

Inquiry-based physics is huge in the physics education research community, and is at the heart of the changes to both AP Physics and NGSS. If you are interested in that kind of thing, you could check out these resources.

http://www2.phy.ilstu.edu/pte/publications/index.html
http://modeling.asu.edu/
http://www.bscs.org/sites/default/files/_legacy/BSCS_5E_Instructional_Model-Executive_Summary_0.pdf

 

[bcrowell]

My impression is that, especially in first-semester freshman mechanics at the college or university level, the traditional lab has simply been eliminated in most cases. Many state four-year schools don't have a lab course at all for that semester, which I think is just a funding-driven decision. At the community college in California where I teach physics, we have about 30 natural science faculty, and I'm pretty sure I'm the only one currently doing a lab course in which students do experiments and turn in lab reports every week for a grade. Most faculty just don't seem to want to do all that grading. They use lab periods for homework help, worksheets, computer simulations, etc. When there are experiments, they don't collect any written work.

Inquiry-based learning is often presented not just as an alternative way of doing lab but as a way of organizing the whole course. In some of these courses there is no textbook at all, and students are supposed to learn everything for themselves. In others, there is a text, but students fill in a lot of the details through inquiry-based learning. These approaches can be fun when done well and when you get a good group of students, but when done badly or with a weak class they can be disastrous. They also tend to be extremely resource-intensive. The more successful ones have often involved a professor plus an army of TAs. This makes them expensive to sustain. It's usually done with gen ed classes. I've done a gen ed physics class that way, with mixed success.

 

[Andy Resnick]

<snip>

T: "what is the value acceleration due to gravity?"
S: "9.8 m/s^2"
T: "Great. prove it."

<snip>.

In general, I like the inquiry approach. However, I'm not sure this is any better than the 'old' cookbook approach. First, you don't 'prove' a particular value of g. Second, the measured value of 'g' is not going to be 9.8 m/s^2 and there is (apparently) no guidance for the student to reconcile their direct experience with 'recieved wisdom'. Third, I suspect that as soon as one group figured out how to measure g, the other groups simply copied their approach rather than independently solving the problem.

Did you summarize the experience by having the students present their findings to each other? That's a vital part of problem-based/iquiry-based learning.

In any case, the Physics Education Group in Washington has a lot of relevant materials (especially 'tutorials in introductory physics') you may be interested in:

https://depts.washington.edu/uwpeg/

 

[fishspawned]

In general, I like the inquiry approach. However, I'm not sure this is any better than the 'old' cookbook approach.

I must respectfully disagree. I do feel that by presenting the procedure as an unknown changes the game plan for most students. The feedback from this initial foray was overwhelmingly positive. They actual felt like scientists, and - although this is only anecdotal - all of the students clearly saw this route as being much better than labs they had done in the past. This may not have been the best lab ever (and likely subject to further tinkering) but it proved to be much better of an experience for all involved.

First, you don't 'prove' a particular value of g. .

You are right and I am, of course, paraphrasing the exact wording when discussing the problem with the kids.

Second, the measured value of 'g' is not going to be 9.8 m/s^2 and there is (apparently) no guidance for the student to reconcile their direct experience with 'recieved wisdom'.

Remember that what this method allows is failure. Failure must be a part of experimentation - something the cookbook method - in my mind - tries to avoid (or at least is not the intention). And the reconciliation - and the discussion that follows when everyone in the class talks about what they did and found out becomes much more of an enriching as a result.

Third, I suspect that as soon as one group figured out how to measure g, the other groups simply copied their approach rather than independently solving the problem.

This may surprise you, but each group had a completely different method from each - (there was a ticker tape approach, a stop watch and dropping a ball method, an inclined plane, even a long exposure camera one!). Their focus in most cases was not in determining a method - which generally came fairly easy (but in some cases very imaginative!) but rather considering how many trials would count as enough to get a good value. Questions of accuracy, precision, and the difference between calculated values vs real world measurements were a larger part of the discussion, and this was very important to me.

 

[symbolipoint]

My impression is that, especially in first-semester freshman mechanics at the college or university level, the traditional lab has simply been eliminated in most cases. Many state four-year schools don't have a lab course at all for that semester, which I think is just a funding-driven decision. At the community college in California where I teach physics, we have about 30 natural science faculty, and I'm pretty sure I'm the only one currently doing a lab course in which students do experiments and turn in lab reports every week for a grade. Most faculty just don't seem to want to do all that grading. They use lab periods for homework help, worksheets, computer simulations, etc. When there are experiments, they don't collect any written work.

...

Bad, bad, bad! Really bad!
Any support for what I say should not be necessary.

 

[Andy Resnick]

I must respectfully disagree.<snip>.

Remember, I said that in general, I like using the inquiry-based approach. My point is simply that when changing the pedagogical approach, the teacher also needs to change their methods. As an example, this past year we focused on improving how error analysis is incorporated- students typically associate 'measurement error' with 'failure'- so we spent time and effort leading the students through a proper analysis and instructing the TA's not to accept "user error" as a source of error.

Another constraint is the amount of time available: students must complete the entire lab- setup to writeup- within 2 hours. The primary reason students must turn in their completed lab at the end of class is to prevent cheating/copying once the students leave the room.

 

[John F. Gogo]

I had mentioned in another thread that I had just started teaching Physics.

I had spoken about the qualities of a Physics teacher and the challenges he/she may face but something I left out was "The Lab". This was something that was a thorn in my side right from the start going back to when I was in high school ( the 80s!). And I was hoping that I could start a thread where other teachers would be interested in contributing their ideas as well.

My experience of Labs, including the ones proposed to me by other Physics teachers have been of a the standard format.
1. A set of instructions
2. The student follows these instructions to get the expected result
3. The student writes a lab report [usually cutting/pasting the procedure into it]

In my opinion, this does not allow a student to make use of scientific inquiry but instead learn how to be a good worker. So I took it upon myself to recreate the labs (which I'm sure many of you have done as well) so that they became centered upon a more student centered approach.

When we were to do the lab regarding gravity and basic motion laws, my lab was the simplest. The conversation was as follows:

T: "what is the value acceleration due to gravity?"
S: "9.8 m/s^2"
T: "Great. prove it."

And that was the lab. I offered little more than guidance following this. What this does is provide several opportunities:

1. Students must develop their own experiment
2. Students will learn that failure is a part of the process
   
3. Students will be forced to realize the importance of both Accuracy and Precision [such as the need for Trials) within their experiments.
4. Procedures will have a value within the lab [i should note that I also insisted that they submit the Procedure to their experiment BEFORE they did it - this I found to be very important]

The experiment was incredibly successful. They were, at first, completely freaked out being left in the ocean without a paddle. But it took no time at all for them to start to critically think about what they knew in order to come up with a very wide variety of experimental procedures.

Another experiment. Two blocks of wood [the ability to add extra weight is there] are provided and students are asked to produce a race between them [on an inclined plane] where one beats the other by 2 seconds exactly. An experiment focusing on friction.

I am sorry for the length of this post but here I stop and simply ask if anyone else has managed to put together similar open ended experiments. I thought this would be a great place to share.

Excellent idea. Failure is just as important as success!