This story is written for Muggle Studies at Hogwarts School. The piece of dialogue I have used is "I think you have the wrong number."
Essay-The Phone
"I think you have the wrong number, Mrs. Sharp. This is not the number for the London Police Station." Rose Weasley told the woman on the other line, thinking privately that perhaps the woman couldn't read very well.
"Oh, never mind, Dear. Thank-you for your help." With that, she hung up.
Rose sighed, and returned to her almost-blank piece of parchment. Almost blank because she had written the words "Essay-The Phone" at the top of the piece of parchment.
She was to write an essay about the phone, and didn't really know where to begin. She also had to write a short story as one of Alexander Graham Bell's children, but she didn't really know where to begin that one, either.
But just then, her mother Hermione came home from her shopping trip to Diagon Alley.
"Hey Mum, can you please give me some help with my essay about the invention of the telephone?" She asked, and Hermione grinned.
"Of course I can help you with your essay; because I grew up with Muggles, I know quite a lot about the phone."
"Enough to cover 870 words?" Rose asked, and her mother nodded.
"Absolutely." So saying, she pulled out her time turner , and said, "How about we see it's timeline together?"
Five minutes later, due to Hermione upgrading her time turner, they had arrived in late 1840's London.
"So, in 1847, a man by the name of Alexander Graham Bell was born here, and it was Mr. Bell who invented the first practical telephone."
Just as she said this, the time turner suddenly glowed.
"What's going on?" Rose asked, and Hermione shrugged.
"It's probably taking us to another important era in the history of the phone. Like, most likely, when he invented the phone."
"When did he invent the telephone?" Rose asked.
"He invented the telephone in July 1874, and all the research he did on hearing and speech paid off in 1876 when he was awarded the first U.S. patent."
"What's a patent?" Rose asked, and Hermione explained that it was a property right granted by the Government of the United States of America to an inventor.
Rose drank all this information in, and wondered what other kinds of phones there were.
"So, when did we start getting the cellphone and everything?" She asked, and Hermione said "Not until much later on, Rose. It may also interest you to know that the word telephone comes from two Greek words, which together mean "distant voice."
"As for the other phones, my grandparents used to have what was called a rotary phone, and they were around till the 1960's."
"How did they work?" Rose asked.
"Well, despite not being from that time, my grandmother taught me how to use one. The way it worked was on a pulse-based system. The user would turn the dial with their finger before releasing it which would cause the dial to return to its starting point. This action would generate a series of electrical pulses which correspond to the selected digit. So, say you dialled 3, then three pulses would get sent down the line to the switching office."
"From then on, we have the phones we have nowadays, like the home phone, and the cellphone. I may have missed a few things out, but I think we should head home." Hermione finished, and that's where they were not five minutes later. Rose wrote her essay, but decided to give the matter of her story a little more thought.
As it was Friday, the Weasleys all met up for dinner, and Rose told her uncles and aunt all about the telephone, and what an awesome invention it was.
Her grandfather was delighted to hear that she had chosen to take Muggle Studies as one of her third year subjects, and said proudly that he too, thoroughly enjoyed it.
As she stood up to use the bathroom, Rose failed to notice the puddle of water on the floor. As a consequence, she ended up bashing her head on the kitchen floor.
When she came to, it was to find an older girl standing over her, looking worried. This was Elsie May Bell, the older of the two Bell daughters, which could only mean that she was Marian Hubbard Bell.
"Are you alright, Marian?" Elsie asked, and Rose nodded.
Elsie smiled, and held out her hand for her sister to take hold of. Then, pulling the girl to her feet, she said, "Come on. Daddy wants to show us his invention."
Indeed Mr Bell had his telephone to show them, and that was when Rose returned to her own time.
"Are you Ok, Rose?" Her father asked, and she nodded.
The next day there were a stream of text messages on her phone about how she was, what she'd been up to, and the usual thing one is normally asked on a cellphone when they haven't been in contact for a while.
However, Rose didn't answer any of these, at least, not right away. She had her essay to write, and began it with the words "There are many wonderful inventions in the Muggle World, but perhaps the most interesting one is the telephone." She carried on from there, putting in good sized paragraphs about Alexander Graham Bell, his two daughters and his invention of the first practical telephone.
She also mentioned him receiving the US patent, and the different kinds of phones there were, leading up to the cellular phone. She even wrote that she had a cellular phone, before ending the essay with the words "There are many inventors in the Magical and Non-Magical worlds alike, but the one I remember in this essay is Alexander Graham Bell, inventor of the practical phone."