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In most college lectures the slides go up and everyone races to copy them before the next click. By the end of the hour you have a copy of something the lecturer will probably upload anyway, and little of what they actually said.
A better plan: get the slides early, use the lecture to add what they leave out, and turn the result into a sheet you can test yourself with.
Should you copy lecture slides word for word?
Not if you can get them another way. In two experiments with science lectures, Marsh and Sink (2010) found that students who had slide handouts during the lecture took fewer notes, needed less time to prepare for the final test in one study and scored better on it in the other.
The ICAP framework from Chi and Wylie (2014) helps explain why copying adds little. It sorts learning activities into four modes, passive, active, constructive and interactive, and predicts that learning increases from passive towards interactive. In its examples for listening to a lecture, taking verbatim notes counts as active, while asking questions and drawing concept maps count as constructive, one level higher.
So the goal is not more notes. It is notes that you had to think to produce.
How do you annotate lecture slides during class?
Start before the lecture:
Download the slides as soon as they are posted, or print them three to a page with lines beside each slide.
Skim them for ten minutes. Put a "?" next to anything you do not follow yet.
Leave the margins empty. That space is for the lecture.
In class, use a short code so you are not writing sentences:
E for an example the lecturer works through, with the numbers.
? for a question you still have, written as a question.
! for anything the lecturer stresses, repeats or says students often get wrong.
→ for a link to an earlier topic ("same idea as the last chapter").
What does an annotated slide look like?
Say a physics slide reads only: "Work-energy theorem: W(net) = change in kinetic energy." Copying that gives you nothing new. An annotated version looks like this:
E: A 2 kg block starts at rest on a frictionless floor and is pushed by a 10 N force for 5 m. Work done = 10 x 5 = 50 J, so kinetic energy = 50 J. From ½mv² = 50, v² = 50 and v is about 7.1 m/s.
?: With friction, is the net work still 10 x 5? (No: net work counts every force, so friction's negative work comes off.)
!: Lecturer said the sign of work is where most marks are lost.
→: Newton's second law; why does the normal force do no work?
If a "?" stays open after class, the Fermi Concept Library has a lesson for every concept in physics, chemistry, biology, mathematics and computing, so you can close the gap the same day.
How do you turn annotated slides into a review sheet?
Do this within a day (see how to recap a lecture on the same day).
Turn each annotation into a question. "E" becomes "Find v for the 2 kg block"; "!" becomes "What sign does friction's work have, and why?"
Write the questions on one sheet per lecture, answers on the back or folded under.
Answer from memory first, then check against the slides.
Come back to the same sheet a few days later, and again before your mid-semester exam.
This works because testing yourself is itself a way of learning. In Roediger and Karpicke (2006), students who took recall tests on prose passages remembered substantially more on tests two days and one week later than students who reread the passages, even though rereading made students more confident.
A large review by Dunlosky and colleagues (2013) rated practice testing and distributed practice as high-utility techniques, and highlighting and rereading as low-utility. A colour-coded copy of every slide sits close to the low-utility end; a question sheet you revisit over several days uses the high-utility ones.
What if your lecturer doesn't share the slides?
Ask, politely and early. You could say: "Could the slides be uploaded before class? Some of us would like to print them and add notes during the lecture." Giving the reason helps.
If not, split each page down the middle: headings and formulas on the left, your examples and questions on the right. And if the slides are online, you still need the lecture to fill the margins; see what the data shows about skipping lectures.
When a lecture example leaves you unsure which method to use on similar questions, the Fermi Problem Library has worked problems with a step-by-step solver that explains the reasoning rather than printing an answer. Rewrite its reasoning in your own words on the review sheet rather than saving a screenshot.
Bring next week's slides with empty margins. For how these sheets fit the semester, see how much mid-semester exams matter.
