Too Late To Love Me I Already Left With His Twins (Lydia and Dave) novel Chapter 327

Lydia POV

“Mom, school was so much fun today! We did a demonstration of Archimedes’ principle in physics, and we also learnt about contact and non-contact forces!”

I raised my eyebrows. “Really? That sounds interesting.”

“It was! We used water and different objects, and our teacher showed us why some things float and some things sink. Then we did the forces thing, too!”

“Slow down, Professor Eli,” I said, laughing. “Let’s start from the beginning. Tell me what happened.”

He took a deep breath, as though preparing to deliver a lecture to an audience that had paid good money for tickets.

“So, first, our physics teacher brought a big transparent container filled with water. She also brought a measuring cylinder, a small metal object, a stone, a piece of wood, and a plastic ball. Before she started, she asked us what we thought would happen if she put each object into the water.”

“And what did you say?”

“That the stone would sink, the wood would float, and the plastic ball would float too. But one boy in my class said that the metal object would float because ships are made of metal!”

I laughed. “Well, he wasn’t completely wrong to bring up ships.”

“That’s what our teacher said! She told us that the question wasn’t simply whether an object was made of metal, but how its weight compared with the buoyant force acting on it. Then she put the stone in the water, and it sank straight to the bottom. The wood floated, and the plastic ball floated too.”

Eli demonstrated the stone sinking with a dramatic movement of his hand.

“Then she asked us why the stone sank. One girl said it was because the stone was heavier than the water, but our teacher explained that we had to think about density, too. She said that an object sinks when its average density is greater than the density of the fluid, while an object can float when its average density is lower.”

I nodded encouragingly. “Good. So what happened next?”

“She took the metal object and suspended it from a spring balance. She showed us its weight in the air, then lowered it into the water without allowing it to touch the bottom. The reading on the spring balance became smaller!”

He widened his eyes at the memory, as though the demonstration had somehow become more magical in the retelling.

“She asked us why the object seemed lighter in the water. Some people said the water was holding it up, and she said that was basically right. The water exerts an upward force on an object placed in it. That’s the buoyant force!”

“Very good.”

“Then she explained Archimedes’ principle. She said that the upward buoyant force is equal to the weight of the fluid displaced by the object.”

He said the words carefully, clearly pleased with himself for remembering them.

“She also showed us a container with an outlet near the top. When she put an object into the water, some water flowed out through the outlet and into another container. Then she measured the displaced water and explained how its weight was related to the buoyant force.”

I smiled. “Oh, that’s a good demonstration. It makes the principle much easier to understand when you can actually see the water being displaced.”

“Exactly, Mom! It wasn’t just something written on the board. We could see it happen. And then we started arguing about the ship.”

“The ship?”

“Yes! The boy who said the metal object would float kept asking about ships. So our teacher explained that a ship isn’t a solid block of metal. It’s hollow, and its shape allows it to displace a large amount of water. The average density of the whole ship, including the air inside it, can be less than the density of water. That’s why it can float.”

“And what did the boy say?”

Eli grinned. “He said he understood, but I think he was just tired of everybody looking at him.”

I laughed. “Poor boy.”

“He was fine, Mom! He actually asked another question about submarines, and our teacher explained that submarines can control their buoyancy by changing the amount of water in their ballast tanks. It was so cool!”

“Okay, that is actually very cool.”

“And then we did forces!”

He was practically bouncing on his feet now.

“Our teacher put a book on the table and asked us what forces were acting on it. One person said gravity, and another person said the table was pushing it up. Then she explained that the book’s weight acts downwards and the normal reaction from the table acts upwards. Since the book was resting without accelerating, those forces balanced each other.”

He paused to check that I was still following him.

I nodded. “I’m listening.”

“So she asked us to push the book across the table. We had to explain what happened when we pushed it gently and when we pushed it harder. She said the push was an applied force, and the friction between the book and the table opposed the motion. When we pushed harder, the book started moving because the applied force was enough to overcome the friction that had been resisting it.”

“Did everyone get a turn?”

“Yes! We took turns pushing the book, and we also tried pushing a pencil case and a heavier stack of books. The heavier stack was harder to get moving. Our teacher explained static friction, which acts when surfaces aren’t sliding against each other, and kinetic friction, which acts when they’re sliding.”

“Look at you,” I said, laughing. “You sound like you were the one teaching the class.”

“I was paying attention!”

“I can see that.”

“And we learnt about non-contact forces too. Our teacher brought a magnet and some paper clips. She asked us to bring the magnet close to the clips without touching them, and the clips moved towards it. Then she explained that magnetic force can act without direct contact.”

He reached for a spoon on the table, then seemed to remember that we were no longer in the classroom and put it down again.

“We also talked about gravitational force and electrostatic force. She rubbed a balloon against a piece of fabric and brought it near tiny pieces of paper. Some of the paper moved towards the balloon, and everybody started shouting.”

I laughed. “I can imagine.”

“It was so funny! One girl thought the balloon was going to pick up the entire paper sheet. And our teacher explained that rubbing the balloon transferred electric charge, allowing it to attract the little pieces of paper. She said the force wasn’t magic, even though it looked like magic.”

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