Intro Physics Labs: Why?

Some of my research these days is focusing on the introductory physics lab. In this post, I will seek to outline some qualitative findings about introductory physics labs at universities and colleges in the USA. I am planning to follow-up these conclusions by doing a survey of a representative sample of physics departments — but that will have to wait until late August.

1. Parallel or Separate?

In most programs, the physics lab runs parallel with the physics course. At Lincoln University, for example, students take Phys 105 and 106 as their two-semester introductory physics sequence, and also enroll in Phys 105L and 106L at the same times. Here, the goal of the lab tends to be focused on reinforcing core ideas. At Penn State, labs “are designed to provide you with hands on experience with the material being investigated in class”. The key concern here is that recent research suggests that labs provide “no added value to learning course content” (Holmes et al).

Less common is a lab that is run as a separate course, sometimes requiring the first course in the introductory physics sequence as a pre-requisite. At Drexel, for example, students take Phys 128 as a separate course. These separate courses tend to focus more on the development of experimental skills and mindsets. At Carnegie Mellon, the purpose of intro lab course 33-104 is “to become skilled at acquiring, recording, and analyzing data, and drawing conclusions from experimental work”.

2. What is the purpose of labs, anyway?

The AAPT lab guidelines focus on the process of “constructing knowledge” and scientific skills, rather than core ideas. Ideally, I think, labs would meet both aims: helping students to enrich their understanding of core physics ideas, while also learning how scientific knowledge is generated experimentally.

In constructing a lab experience, core ideas and scientific skills will need to be interwoven. Could we say that a lab is successful if students only practice core ideas? Could we say it is successful if students only learn scientific skills? I would say that the former is not acceptable, but the latter might be.

3. What labs are being done?

Cookbook-style lab manuals are nearly ubiquitous. Most of these seem to have been written locally, but have the same format: an overview of the relevant physics (which students rarely read), then step-by-step instructions for what students should do in the lab, and finally some questions.

There is variation in how students are assessed. Often, there is a pre-lab quiz. Written lab reports are common (often 1 per group of 1-3 students), as are worksheets that need to be filled in.

Most labs are 3-hour sessions, with a new experiment each week. In some places, a 1-hour lecture precedes the lab session. In others, experiments stretch over two weeks.

Some manuals seem to try to scaffold students from this mode of highly-structured inquiry (where direct instructions are given) toward guided inquiry (where, instead, students are given goals and broad guidance). I wasn’t able to find any lab programs that aim for open inquiry.

4. How do AP, IB, and Cambridge A-Level lab expectations compare?

For all three of these programs, labs are expected to occupy about 20% of the instructional time. In the AP, IB and A-Level classes, labs are explicitly expected to build toward independent student work (ie: open inquiry). AP labwork is not assessed directly, while IB students submit a lab report for external assessment, and A-Level exams include a substantial practical component.

It seems to me that colleges and universities have substantially lower expectations for student performance in labs than is found in the AP, IB, and Cambridge A-Level courses.

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

w

Connecting to %s