Simran had made it to the back of the classroom before people had finished setting up -- most seemed to be able to get through unassisted, including Mr Doley, despite his evident boredom with the lesson.

Truly, she felt a little bad for making such a good student out of his mind, but she sent him a thumbs up somewhere in between his stopwatch readings.



There was something rather calming about pendulums and their swinging, and Simran made a mental note to get herself a Newton's cradle for her office just so she could have something else to procrastinate grading papers with.

Thank goodness for Miss Smethwyck, though, for snapping her out of her pendulum-induced hypnosis before she got too carried away. Why an oscillation? Oh, well. She knew the answer for this, at least. "Many things swing. For example, if I were to slide your pendulum off the clamp and swing it at someone's head, that would be a pendulum swing."

"An oscillation, however, is a word for a specific type of swing,"she said, her right index finger now following the movement of a nearby pendulum. "It describes a periodic motion, where the restoring force acts in the opposite direction to the displacement of whatever it is you're measuring. We call it simple harmonic motion."

And then drawing nearer, she lowered her voice slightly. "If you want extra reading on the subject, feel free to stick around after class and I'll get you something."



Oh, quite a nicely set up apparatus was going on here. The Slytherin prefects seemed to be on a roll today. "Excellent setup, Miss Mallari."



But on the subject of well-set-up apparatus, this one was rather... not. Not that it was terribly set up, but there were so many knots that Simran almost had a headache trying to imagine disassembling it.

"Master Dakest, you do know that more knots increase friction, which can affect your results, yes?" Summoning a spare pendulum bob, she picked up the spool of string and cut a new length, something she approximated to a half metre even though it was about 58cm in reality.

"A double knot on the pendulum will do, if you tie it tight, it won't fall off." We following? "And a loop on the top is the most efficient considering you can just sliiiiiide it onto the clamp."

Like so.

Merry Christmas, Lucas Dakest, Professor Sandhu just set up your apparatus for you.



At the Gryffindor prefect's tone, something seemed to simmer in her veins. Was it her blood? How quickly it boiled these days without Amrita to nag at and Jasmine to coo over.

"And that will be 3 points from you for your lack thereof, Miss Merriweather," she said frostily. "And your blatant lack of respect."

She drew nearer, voice still low, but the patented disappointed brown parent look in her eye. "I can put up with and occasionally enjoy your sad attempts at wit in lessons with your peers, dear, but when the younger students are around, I expect you to be an example. If that seems too much to ask of you, I will be more than happy to bring it up with your head of house. Do I make myself clear?"

Hm?



Oh, Kaiser, dear, what ever were you doing? Simran made her way over to his desk and picked up his stopwatch, and then held it out to him. "Time ten oscillations, dear, and then adjust the length of the string."

"And don't forget to record your results!" Maybe someday all her students would listen when she gave instructions.



Well, truthfully, Professor Sandhu had planned a whole host of introductions to the night sky, but the weather had decided to one-up her and she wasn't really in the position to tell the weather to kindly buzz off.

At least Anahera seemed to be doing well, even if she looked liable to fall asleep in the next few minutes.



And with Miss Newton, as always, precise to a flaw. Simran nodded in approval at the girl's setup before moving back towards the front.

Clapping her hands twice to get their attention, because her throat was dry and she didn't quite want to scratch it further before she had some tea, she waited until eyes moved from pendulums to her person. Did she have the room yet? Wonderful.

"Now you've all become acquainted with the simple pendulum and learned the relationship between the manipulated variable -- the length of the string -- and the time taken for the pendulum to oscillate. Your conclusion would be that the shorter the string, the faster the oscillation -- or the higher the frequency."

The conclusion wrote itself out on the board, and the associated equation as well. "This experiment is not only important to illustrate the effects of simple harmonic motion, but is also the simplest way to derive the value of gravitational acceleration." SURPRISE! Bet they didn't think pendulums had anything to do with astronomy at all.

"Either way, we won't be deriving that right now," she said, looking out over the room. "As you were performing the experiment, I'm sure it was difficult to keep your results as accurate as possible, especially with so many moving parts."

"Now, can you all tell me what could have possibly gone wrong in this experiment? Or in any experiment, for that matter?"


OOC: Thanks for participating in the mini-activity, guys! Now we're on to Question 2. You'll have about 24 hours from the time of this post before we move on!