"Sid's got more chips than me!" protests Petra.

"No I haven't!" I reply, guarding my plate in case she tries to swipe one of mine.

"I gave you exactly the same amount," says Mum.

"He's definitely got more," Petra insists.

I quickly start eating mine, saying, "No I haven't," through mouthfuls of chips.

"Not-a-clue!" she hisses.

"Empty-space-head!" I hiss back.

"Will you two stop bickering for one minute!" demands Mum, looking exhausted.

As if that's ever going to happen.

You see, Petra and I are twins.

Up to the age of seven that was a good thing. We got on brilliantly, shared all of our toys, played endlessly together and liked the same TV programmes. But now we're ten, it's a bad thing. Although Mum always buys us identical things like pencil cases and socks and alarm clocks and always goes out of her way to be "fair", our interests are now very different.

Petra's interested in astronomy, telescopes... that kind of thing.

I'm into mystery novels, "whodunits"... that kind of thing.

When I'm annoyed, I call her "Empty-space-head".

When she's annoyed, she calls me "Not-a-clue".

Petra counts the chips on her plate, while I finish mine off.

"He had more," she growls.

We glare at each other.

The next day after school, I'm in a bad mood. Petra managed to get into the house before me and grab the comfy green armchair, the one we both love. The rule is whoever gets the green chair first chooses the first TV programme we watch. To make things worse, I have maths homework, set by Mr Clifton, who Miles Frost says looks like a rat. Petra has already done hers.

I'm in my room, angrily rooting around for a pencil in my desk drawer, when I spy something strange. It's a flat green disc, about the same size as a watch but without a strap. Like a watch, it has a digital screen but this is blank. Above the screen in small writing are the following words: Danger - Max Use - Once Daily. Below the screen are two buttons labelled "ON" and "GO".

I frown and turn it over in my hands. Its back is silver and shiny. What is this thing? And how did it get into my desk drawer? Did I get it from a cereal packet years ago and just forget about it?

I shrug my shoulders and press the "ON" button.

There's a clicking sound and the screen flickers into life:

10 SECONDS TIME FREEZE , it declares.

Time freeze? What does that mean? Is my finger going to freeze in ten

seconds? Do I need to put the disc in a freezer for 10 seconds before it starts doing... something?

I put it in my pocket and turn to Mr Clifton's maths homework. It's about symmetry. I hate symmetry.

A short time later, a delicious smell wafts out of the kitchen: dough, tomato and mozzarella. It's pizza night and Mum's homemade pizza is awesome.

Petra's already sitting at the kitchen table when I get there. I take the chair opposite her; the days of us sitting next to each other are well over.

Mum has two plates in the air and as she lowers them, one towards me, the other towards Petra, surprise, surprise, Petra blurts out, "Sid's got more than me!"

I can't face another argument and for some reason I pull that green disc thingy out of my pocket and flick the "ON" button.

There's the click and the screen lights up, stating 10 SECONDS TIME FREEZE, just like before.

As Petra is about to complain more, out of curiosity or boredom or both, I press the disc's "GO" button.

A split second later, every single thing in the kitchen completely freezes. I don't mean in the cold way, I mean in the stopping dead-still way. I'm telling you: Mum has frozen like a statue, the two pizza plates outstretched in her hand. Petra is completely motionless, her snarling upper lip caught still in time. The plant that was blowing in the window breeze a moment ago is rigid. Everything has frozen, apart from me.

The display on the disc suddenly starts counting down.

9, 8, 7...

I quickly grab the plate Mum is handing to me, take a slice of pizza and gobble it down as quickly as I can.

...3, 2, 1, 0.

ONLY 4 TIME FREEZES LEFT, flashes the screen and then goes blank.

Everything in the kitchen suddenly comes back to life. Petra looks at her plate and then at mine. "I must have been wrong," she says. "I've got more than you."

I nod, swallowing the last piece of the slice I grabbed, while sliding the green disc below the table.

"Great," says Mum with relief, "now eat up because I've got some apple crumble for pudding."

Petra happily chews her way through a pizza slice but I'm now the one who has stopped. I'm looking down at the disc and thinking only one thing: that was incredible!

Chapter 1: Activities

Comprehension Exercise: Quiz - Test your knowledge of the chapter with these five brain-busting questions.

Purple Mash Activity:In the story, Sid finds a device that freezes time for ten seconds at a time. The device will only work five times. How would you use a gadget like this. Think of five situations where it would be really useful.