Farhan
Rizwana Ashraf에 의해One day, James came to Robert and David, full of excitement. “Hey, come here! I’ll show you some magic!” he said eagerly.
James tore a sheet of paper into tiny pieces and rubbed a glass rod on his hair. When he brought it close to the paper bits, they clung to the rod.
“Look! The paper is getting attracted to the glass,” he said proudly.
“Wow! Now show us something that repels,” said Robert.
“That part I don’t know,” James admitted.
“Alright then, let me show you some magic,” said Robert with a smile.
He took a plastic ruler and a piece of a plastic bag, rubbed both on his hair, and brought them close together. To everyone’s surprise, they pushed away from each other. But when the same plastic was brought near James’s glass rod, it got attracted.
“Sometimes it repels, and sometimes it attracts—what kind of magic is this?” asked David curiously.
“This isn’t magic,” explained Robert. “When plastic is rubbed on hair, it gains electrons and becomes negatively charged, while glass loses electrons and becomes positively charged. Like charges repel each other, and opposite charges attract.”
Just then, David remembered he had a metal ruler. “Metal is the best conductor,” he said. “That means it can easily lose electrons, so it should develop the strongest charge.”
But when he tried it, the metal ruler didn’t attract even a single piece of paper.
Can you figure out why that happened?
