Work Text:
"All right!" Grace called out to his class, clapping his hands together to gain the pebbles' attention. "Come on everyone! Focus up here please!"
Slowly, the gentle chatter and chirping of the classroom quieted down to a soft humming as the students did their best to behave for their favorite teacher. They loved his lessons, always fun and interesting in one way or another, especially when he decided to cover topics and concepts that were new to Erid.
"Thank you," he said gently, letting the translator speak for him so his kids could understand him properly. "So today, we're continuing to cover the idea of forces. Who can remind me of what a force is?"
Immediately, the group of pebbles raised their small little arms, hoping for Mr. Grace to call on them, hoping for the chance to prove themselves to their teacher.
"Golem!" Grace called, pointing at one of the larger students. "What is it?"
"A force is a push or pull on an object that changes how the object interacts with its environment!"
"Very good!" Grace praised. "Who can give me an example? Iggy!"
"Pushing my sibling down the stairs!" They screamed out, climbing on top of their friend as they spoke.
"Um…" Grace hesitated for a moment. "Yes, that is a use of force, but let's not do that, okay? Also, get off of Aron please, Iggy. We don't climb on our classmates. Does uh, does anyone else have a safe use of force?"
"Running and stopping?" Rhydon offered, their notes squeaking with the lack of confidence in their answer.
"Yes!" Grace cheered, giving them two thumbs up. "Exactly! That would actually be a use of force in 2 different ways because you are using force to start moving and then you are using force again to stop moving. Good job, Rhy!" He praised.
Turning to the board, Grace began jotting down a simple problem, Newton's Second Law that stated that the force of an object is equal to its mass times its acceleration - a simple enough equation for the pebbles to get started with.
"Okay, now that we know what a force is," Grace began, scribbling on the board behind him a crude drawing with different values labeled, "let's do a problem with one. We're going to be using Newton's Second Law that we talked about yesterday to solve this one: force is equal to mass times acceleration. So, for this example, we have a trebuchet that launches a rock that weighs 10 kilograms at a rate of 20 meters per second squared. How much force does the rock have when it leaves the trebuchet?"
Multiple pebbles claws went up in an instant, their brains moving faster than Grace could have ever hoped for his to. God, he loved these kids… not like that, strictly in a non-weird way.
"Okay, let's see here," Grace said, making a game of it. "Onix! What did you get for an answer?"
"200 Newtons!" They called back.
"Exactly!" Grace cheered. "200 Newtons," he said, writing it on the board with a line under it. "Now-"
"What is a trebuchet, Mr. Grace?" Luna, a smaller Eridian that sat in the front, asked.
"Oh, a trebuchet is a type of catapult," Grace explained gently. "It uses force to launch something by moving an arm with weight at the end of it."
The pebbles only looked a him more confused than before. This wasn't working.
"It sounds cool," Aron said, speaking up gently, Iggy still hanging off of them. "But we've never seen one and your drawing isn't great, Mr. Grace."
Ouch, that hurt a bit, but Grace understood. He wasn't an art teacher for a reason - stick figures were as good as it got for him.
"Okay. Hmm…" Grace mused to himself for a moment. "What if we were to build one?" He offered, as an idea hit him to really get the kids interested in physics and engineering. "Just how sturdy are you guys?"
Excited energy filled the room instantaneously as the pebbles realized what Grace was getting at. They were going to be the rock in his problem.
"Very! Very sturdy!"
~~~
God, this reminded Grace of teaching his kids back on Earth, when he would light their hands up with rubbing alcohol for fun as a reward when his prize box ran out. It was always done safely with the fire going out immediately. They'd loved it so much and he was sure the pebbles were going to love this too.
"So, we're making this for a demonstration?" Rocky asked, helping Grace put the boards of xenonite into the proper position and locking the weight into place.
"Yep," Grace said. "They didn't know what it was and I figured that a physical demonstration would be best."
Rocky nodded in understanding, not expecting Grace to do much of anything that was dangerous with it, even when they made a net of xenonite net with give to it to catch whatever he launched, preventing it from going too far and letting it land gently on the ground in a safe way. He trusted his friend. Besides, the kids were excited to see what Grace was making for them. What's the worst that could happen?
~~~
"Okay everyone!" Grace called. "Form a nice single file line along the side here," he said, waving a hand to where he wanted them to go.
All of the pebbles chittered and chattered in excitement, looking at the large trebuchet that Grace and Rocky had built for them. Their suits held them well as they moved in glee, ready for it to be their turn to go where the decent sized Rocky was now.
"This is a trebuchet," Grace explained, ensuring that all of the pebbles were a safe distance back for now. They'd be getting a closer demonstration soon enough. "Remember from our problem yesterday? This one has a rock that weighs 5 kilograms and it accelerates at a rate of 10 meters per second squared. How fast will this rock go when I do this?" Grace asked, pulling a lever down and sending the weight down to the planet surface due to gravity.
The pebbles watched in awe as the rock went flying, soaring through the air, landing on a xenonite net a little ways away, moving faster than they had ever seen, especially while it was in the air.
"50 Newtons!" Graveler yelled out, first to get their attention back to Mr. Grace's question.
"Correct!" Grace yelled back. "Get on up here!" He told them, crankling the lever back to its right position as it locked into place, ready to launch its next victim.
Scrambling over, Graveler climbed into the basket and curled into a ball, ready to be the first pebble to fly on Mr. Grace's machine.
"You ready?" Grace asked gently, double checking the system and his student's willingness.
"Yes yes yes!" Graveler cheered. "Send me! Send me!"
"Okay," Grace shrugged, pulling the lever down again as Graveler went airborne.
"Weeeeeeeee!" They screamed, notes happy and high pitched until they hit the net Grace had set up.
"You okay, Graveler?" Grace called over.
"Again again again!" They cheered as the pebbles began to fight each other to climb into the basket next.
"Here's the deal everyone," Grace yelled, silencing their chirps. "Form a line for me and everyone gets a turn for each question they answer right, okay?"
~~~
Standing outside of the dome, Rocky wasn't sure how to react, especially as Adrian stood by his side, watching as pebble after pebble went flying through the air, landing safely into the net and then climbing into the back of the line over and over.
"Please," Adrian began, their voice tired and twinged with disbelief, "go stop him before one of their parents comes by and sees this."
Entering into the dome, Rocky wasn't sure what to say until Grace saw him first, cranking the lever back into its proper position like he had been after sending each and every pebble off.
"Oh, hey Rock!" Grace waved, a big smile on his face as they pebbles brimmed with excitement. "Do you want a turn?"
And that was how Rocky found himself being sent into the air for a second time in his life, this time by his friend who had very little concern for safety when fun and mad science was involved.
Hitting the net that Grace asked him to put up, Rocky now understood its purpose and had one question for Grace.
"Can I go again?"
A large grin appeared on Grace's face as he nodded, preparing the trebuchet to go again, letting Rocky into the line behind the pebbles as they all continued to get launched across the beach.
Over and over, pebble after pebble with Rocky occasionally in the mix, the Eridians were launched, finally feeling the freeing sensation of being weightless and understanding physics better than before.
"Hey!"
Rocky and Grace immediately froze, one in the basket and the other with a hand on the lever. Adrian had come and they didn't sound too happy.
"Send me, Grace," Rocky whispered. "Do it. Get me out of here."
"Nope," Grace muttered back. "If I have to deal with them, so do you."
"No loyalty. To think I burned myself up for you and nearly died."
"To think I turned my ship around and nearly starved on my way here," Grace snapped back.
"Hey!" Adrian yelled at them again. "Rocky, I told you to stop Grace, not join him."
"Oops," Rocky shrugged. "It looked like fun and the pebbles are enjoying it."
"Yes yes yes!" The class cheered. "Very fun! Very much fun!"
"Well," Adrian sighed out, their voice twinged with a bit of mischief, "let me have a turn. To make sure it's safe of course."
Grace and Rocky immediately broke down in chuckles - Adrian was going to love this.