An excellent way for any science teacher to practice differentiated instruction is by tailoring how we give (and grade) lab assignments. Labs can be inquiry-based or not, open-ended or not, even mandatory or not, and each of these is a method of differentiating in the classroom. I'd like to point out a few practices I've been using that qualify as differentiated instruction in the physics classroom, particularly in lab assignments.
(A good primer on differentiated instruction in general can be found at the website for the National Center on Accessible Instruction Materials at CAST, Inc.)
1. Lab directions on PowerPoint
A major problem for students who are less than meticulous is that they are easily distracted. Especially if they feel rushed, they tend to skip large sections of the directions. To address these students, I have been putting our lab instructions in PowerPoint slide shows, which students can then retrieve to their school-issued laptop. It's harder to accidentally skip 4 slides than it is to skip 4 lines in a paragraph.
Of course, it's also easy for me to delete 4 slides from the procedure for advanced classes. In fact, there are several labs for which I give no procedure at all with AP physics students--a practice that simply doesn't work in my Conceptual Physics classes.
Another nice benefit to using PowerPoint is that I can easily embed photographs or videos of our lab setup if I want to aid students in understanding exactly what to put where. As they say, a picture is worth a thousand words.
Of course, this is within the context of labs in actual lab notebooks, and not as worksheets. I have students use composition notebooks that do not leave the classroom. This leads me to the next practice I want to share:
2. Labs do not have to fit into class time.
Particularly in my AP physics classes, I am an advocate of requiring students to come in on their own time. I assign them at least one lab per marking period for which absolutely no class time is allotted. Before school, after school, during lunch... students will have to find a time to come in with a lab partner or two (I don't assign these lab partners and I don't think teachers should even try in this situation). I am comfortable taking the equipment to a colleague's room if students request to work during study hall... provided that teacher agrees, of course. I've only ever had one colleague decline.
By the second marking period, students understand that lab work is not constrained to scheduled class time. Consider the impact this has on the labs we do during class time; I can tell students that if they didn't finish, they're welcome to come in whenever they have time and complete their measurements. They don't protest, because they already have had to do that before. In fact, for many students it removes the stress that comes with any timed assignment. This allows these students to perform better on the assignment, and to learn the material at a pace that encourages retention. And it gets students to feel comfortable coming in to my classroom outside of class. There is no way to overstate how important that last point is.
3. Don't help.
I have a tendency not to answer students' questions during lab. There are exceptions, but usually what they are really asking is for the teacher to do or explain something that they are supposed to be figuring out themselves. So I repeat the question back to them, or I tell them I don't know the answer but I'm hoping they'll figure it out so I can publish it. It's amazing how quickly students start turning to other lab groups for ideas and clarification.
The "don't help" practice dovetails nicely with not giving a procedure for the lab.
These are three practices that I've introduced over the years in order to make lab assignments more enjoyable for me and more educational for my students. At the time I started each, I hadn't even heard of differentiated instruction. But I had heard of playing to a student's strengths, remediating their weaknesses, and working individually with students on their specific difficulties. And I'm pretty sure that's all differentiated instruction really is.