"And on the other hand, those..." he's looking at Bruce now, eyes narrowed, "...who may expect to be simply handed the benefits of this knowledge without working for them... will find that no such conveniences will be extended in my classroom. Potter." The snap of the last word is so sharp that Neville, on Bruce's other side, startles and nearly falls out of his chair. "Tell me, what I would get if I added powdered root of asphodel to an infusion of wormwood?"

(This information is in chapter eight of their textbook, mentioned briefly in a sidebar about the importance of distinguishing infusions from decoctions and a horror story about some guy trying to make an energy drink for a party and accidentally draught-of-living-deathing his entire social circle.)

The potions master is ignoring Hermione. He called on Bruce.

Aaaaaaaaa? What did he do this time?!

"The the the draught of living death? Professor?" Oh no he sounds like Professor Quirrel

For approximately four seconds, Bruce's evident terror is deeply satisfying.Then Severus processes the even more evident fact that answering this somewhat unfair question correctly, while stammering in terror and still trying to be deferential about it, is .... perhaps the single least James-Potter-like behavior which any human person has ever displayed within his field of view. Quite possibly ever anywhere, really.

He frowns.

What he should say here is, of course, ah, you thought you would read ahead to show off, did you?, all the better to start in on an educational rant about the difference between knowing something in theory and actually being able to do it in practice. He's been storing up snarky spiteful comebacks for two decades, it should be so easy to do this. For some reason when he reaches for it it's not there. "...correct," is what comes out of his mouth instead, "one point to Gryffindor for being prepared for class," and he cannot, actually, end that sentence with the words Mr. Potter, so he just... doesn't, and instead snaps in the general direction of the other Gryffindors, "Let us hope the rest of you are prepared to keep up. I am not in the habit of coddling laziness." There, that's a perfectly normal thing for him to say, everything is fine. "We will begin now, and you will turn in your first attempt at the Cure For Boils at the end of this class period." He waves his wand, and the chalk-scribing charm, perhaps the only useful thing he ever learned from Andromeda Black before she wrote him off as unacceptably evil, prints instructions neatly onto the blackboard for his preferred formulation of the introductory potion. Those students who have read ahead in their textbooks may notice it is not the same as the one which appears therein. 

(The simplified version which appears in Arsenius Jigger's textbook is easier for eleven-year-olds not to screw up, but Professor Snape's personal teaching philosophy is that they should simply learn not to be careless idiots. Dumbledore made him spend five straight summers comprehensively verifying and improving all the safety wards in the potions lab before he let him alter the curriculum in this way, but he did eventually satisfy the old mother hen that none of his precious children will so much as need a trip to the hospital wing even if they do every step completely incorrectly and now he is free to require them to actually weigh their ingredients to specific error tolerances instead of eyeballing them and worrying about that only for less forgiving recipes, and to perform the more complicated series of heating and stirring cycles which if omitted entirely makes the potion more stable but worse, and if attempted imperfectly tends to cause it to explode.)

Blackboard information which doesn't appear anywhere else! It must be written down immediately before doing anything else whatsoever!! Scribble scribble.

Bruce is still deeply rattled but he appreciates the neat and legible blackboard writing a lot. He starts carefully measuring out each ingredient he needs and putting them all in separate little piles and containers so he'll have them all right there when he needs them.

Ron is, shall we say, a better cook than he is a baker. (He's eyeballing his ingredient amounts.)

Draco complains to his tablemate (Theodore Nott; one doesn't simply split up a Crabbe-and-Goyle, they're sitting together behind him) that he also knew the answer to that question, because he very responsibly read all his textbooks in advance too (1). "Why does Potter get a point! Unfair!"

(1) he didn't want to do this, mind, he complained the entire time, but he's obviously not going to admit that in front of the Gryffindors

"Mr. Malfoy, the point of calling upon students is to check whether they are prepared for class. I will not insult you," or more to the point, your father, who is the superintendent of the Hogwarts board of directors, "with the implication that you might not be." 

... oh. Okay then.

Back on the Gryffindor side of the room, Neville is trying to follow Bruce's example, but he keeps dropping things. Seamus, fiddling with the burner to understand how it works, is absolutely no help on this front. Dean, on the other hand, has the level of patient chill with cooking-like implements intrinsic to all older siblings who've ever had to keep a four-year-old from trying to Help a little too much, and putters contentedly through his task at a normal and healthy speed, eyeing Hermione's frantic notetaking next to him with mild concern. 

When Snape's attention is definitely elsewhere Ron whispers to Bruce. "What a git. Asking random questions just to mess with you. And of course Malfoy is going to ooze all over him."

Someone taking his side out loud with words is very reassuring!

"Thank you!" he whispers back. Also he realizes a downside of his strategy, which is that he's been hogging the shared measuring cups. "I think you have too much beetroot." He nudges the appropriate cup over to Ron's side of the table.

Ron does not think "You have too much beetroot" is a sensible or polite response to "that teacher was so unfair to you" but it's a very Bruce response. He rolls his eyes a bit and measures his shredded beetroot and scrapes some of it back into the bottle.

Many teachers would swoop down upon Ron at this point with a lecture about how you Never Ever put decanted ingredients back into their containers.

Severus Snape, however, is of the firm belief that anyone who could not be bothered to read their textbook, which is already a masterpiece of excessive handholding, is not going to learn from being merely told, and needs to learn the hard way. He glances in Ron's direction, judgmentally, and then ignores him in favor of taking notes on what percentage of the classroom is successfully performing each of the steps. Septima Vector, who collects this kind of data like normal people collect decorative knickknacks, asked nicely.

Correctly following the directions: Potter, Granger, Thomas, Malfoy, Nott, Greengrass, Patil. (7/18, 39%)

Not following the directions (on purpose): Weasley, Parkinson, Zabini, Finnegan, Davis. (5/18, 28%)

Not following the directions (but trying to): Longbottom, Brown, Crabbe, Goyle, Bulstrode, Roper. (6/18, 33%)

This does mean, on the bright side, that it's fairly easy to carry on a conversation during Potions class once everybody gets into swing, since the classroom is full of ambient clattering and crackling and Snape does not actually care so long as you stay at your table and are doing something basically recognizable as attempting the activity.

Hermione, once she looks up from her notes and detects this, hisses over to Ron from her table, concerned and alarmed. "On page 2 of Magical Drafts and Potions it specifically says not to put ingredients back in their bottles after you pour them out!"

"Eh, don't be a worrywart," pipes up Seamus, "that only really matters if you - ow - " (he poked his cauldron while he was talking and burned his fingertip, which doesn't in any way cause him to alter the course of his sentence) " - if you aren't careful with it."

Hermione sort of... stares at him in bewilderment for several seconds, caught between her conflicting desires to recite the dictionary definition of the word 'careful', to recite the designated first aid steps for minor burns, and eventually says, incensed, "Rules always matter!" 

Seamus scoffs and goes back to crushing beetles with great enthusiasm.