Demi Cartwright, 17, from Telford, looking on Facebook

Simon is upstairs in his bedroom. You know he’s safe because you checked on him half an hour ago, before settling down to watch EastEnders. Your 14-year-old was watching DVDs, nothing unusual in that. His computer was switched off and his phone was on his bedside table. He grunted his acknowledgement when you peered around his door. Oh well. It’s better than being ignored.

Sophie, meanwhile, is writing an essay in her bedroom. She’s been given plenty of homework for the summer holidays and is keen to make a start. You smile, inwardly, she’s such a good girl for a 13-year-old. Why can’t Simon be more like her? You take a cup of tea and plate of biscuits into her room then leave her to complete her essay, sighing to yourself as you pull the door to.

All hunky dory, right? Wrong. The secret lives of teenagers are far removed from those that we’d like to believe they lead. The moment you exit Sean’s bedroom he’s straight on his mobile telephone, texting friends and telling them to call round when you’re at work tomorrow. He won’t, in fact, be taking the dog for a walk, though he’ll tell you he has.

Sophie, meanwhile, sniggers to herself when you leave her bedroom. She closes the Word document that you thought contained her essay. Silly you. She switches on her mobile phone and uses it as you’d use a radio, listening to the latest tunes. She clicks on another icon on the bottom of her computer screen and peruses the virtual aisles of Next. She’s seen a dress she’d like, she’s stalked it for weeks and now that there’s 50 per cent off…..

Teenagers consume media like no other generation. The technologically-astute generation rejects such fangled old school gadgets as radios, cd players and newspapers because the information and entertainment they provide is freely available elsewhere.

Few teenagers read newspapers and hardly any listen to conventional radio stations, opting to visit online sites streaming for free music. Facebook is among the most popular internet site, enabling youngsters to network from the safety of their bedrooms.

Demi Cartwright, 17, is an A level student at Thomas Telford School, in Telford. She says: “Facebook is the main site for people my age. It’s great because you can talk to your friends in private and have conversations that are as long as you want them to be. All of my friends are on it. Twitter tends to be for people in their twenties and up.”

Demi has owned her own mobile telephone for four years and is constantly sending or receiving texts. She adds: “If we want to arrange to meet up, we’ll do it by text. But then we’re always on the phone as well. Facebook, text or phone, it’s what we do all the time.”

She eschews the aisles of HMV when she wants to listen to tunes by Lady Gaga or James Morrison. Similarly, she’s never bought a newspaper. “Why would I?” she says. “I can get my news or information from Google, BBC.com or similar sites.”

Demi says: “If you listen to the radio, you have to listen to lots of adverts and the djs also waffle on. Plus, there’s lots of music you might not like. So I listen to music online. My parents know that I’m always on Facebook, but it’s not really a thing for their generation. Things have moved on. It’s no longer TV, radio and landline telephones, it’s Facebook, online music and entertainment, social networking and mobiles.

“We love going to the cinema but it’s annoying that we have to pay up to £7.80 once you’re over 16. Me and my friends, thankfully, get away with looking like we’re 14, so we can pay a little bit less.”

The browsing habits of teens have hit the headlines after 15-year-old Matthew Robson became the talk of Tokyo. The south London pupil compiled a report on How Teenagers Consume Media, which he wrote during a work experience placement at Morgan Stanley. He laid out the world according to teens, where the PC is a radio, the mobile phone is a stereo and texting machine, the DVDs are pirate copies and nobody uses Twitter.

Demi adds: “Technology is changing so quickly and we use it to lead the lives we want to live.”