Eric threw him a sympathetic glance. “Let me show you something fun,” he shouted, producing a plastic ruler from his pocket. He brandished it in front of George’s nose. “Do you know what this is?” he asked at top volume.

“A ruler?” said George. The answer seemed a bit too obvious.

“That’s right,” cried Eric, who was now rubbing the ruler against his hair. “Watch!” He held the ruler near the thin stream of water running from the tap. As he did so, the stream of water bent in the air and flowed at an angle rather than straight down. Eric took the ruler away from the water and it ran down normally again. He gave the ruler to George, who rubbed it in his hair and put it close to the stream of water. The same thing happened.

“Is that magic?” yelled George with sudden excitement, completely distracted from Annie’s rudeness. “Are you a wizard?”

“Nope,” said Eric, putting the ruler back in his pocket as the water ran down in a long straight line once more. He turned off the tap and switched off the radio. It was quiet now in the kitchen and Annie could no longer be heard in the distance.

“That’s science, George,” said Eric, his whole face shining. “Science. The ruler steals electric charges from your hair when you rub the ruler through it. We can’t see the electric charges, but the stream of water can feel them.”

“Gosh, that’s amazing,” breathed George.

“It is,” agreed Eric. “Science is a wonderful and fascinating subject which helps us understand the world around us and all its marvels.”

“Are you a scientist?” asked George. He suddenly felt very confused.

“I am, yes,” replied Eric.

“Then how can that” – George pointed at the tap – “be science when science is killing the planet and everything on it? I don’t understand.”

“Ah, clever boy,” said Eric with a flourish. “You’ve got right to the heart of the matter. I shall answer your question, but to do so, first I need to tell you a bit about science itself. Science is a big word. It means explaining the world around us using our senses, our intelligence and our powers of observation.”

“Are you sure?” asked George doubtfully.

“Very sure,” said Eric. ‘There are many different types of natural science and they have many different uses. The one I work with is all about the How and the Why. How did it all begin – the Universe, the Solar System, our planet, life on Earth? What was there before it began? Where did it all come from? And how does it all work? And why? This is physics, George, exciting, brilliant and fascinating physics.”

“But that’s really interesting!” exclaimed George. Eric was talking about all the questions he pestered his parents with – the ones they could never answer.

“Shall I carry on?” Eric asked him, his eyebrows raised.

George was just about to say “Oh, yes please”, when Freddy, who had been quiet and docile up till then, seemed to pick up on his excitement. He lumbered to his trotters and, with a surprising spurt of speed, he dashed forward, ears flattened, hooves flying, towards the kitchen door.

“No-o-o-o-o!” cried Eric, throwing himself after the pig, who had barged through the door.

“Sto-o-o-op!” shouted George, rushing into the next room behind them.

“Oink oink oink oink oink oink!” squealed Freddy, who was obviously enjoying his day enormously.

© Lucy and Stephen Hawking 2007

George’s Secret Key to the Universe by Lucy and Stephen Hawking is published by Doubleday on September 13, £12.99

Buy the book here for £11.69 (free p&p)

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