‘Maxwell’ by Chris Robbins
The boy and the girl were about to wash their hands. I won’t name them as they are just an ordinary boy and an ordinary girl about to do an ordinary thing, and are very much like you and the people you know. The tap they were about to use had two short levers at the base and a single, tall, curved tube that arched over the metal sink. Pull the left lever down and the tap delivered hot water. Really hot water. Pull the right lever down and the tap delivered cool, refreshing, cold water.
The boy and the girl were mindful of what they had been told when using the tap; always turn the cold water on first and let it run for a few seconds before putting your hands in the stream of water. The boy had once ignored this and had scalded his hand. As I said, the left lever delivered really hot water. The boy pulled the right lever and waited. The girl put her hands in the stream of water. "It’s too cold," she said, pulling her hand back. "Put some hot in it."
The boy pulled the right lever a little and after a few seconds he turned to the girl.
"Try it now," he suggested, "it should be getting warmer." The girl put her hand back into the stream of water. It still wasn't warm enough. The boy turned on the hot tap a little more.
"That’s better," the girl said as she reached for the soap and began to wash. "I wonder how hot water knows it's hot, and cold water knows it's cold, and how they agree to be warm when you mix them," the girl pondered aloud.
"That's easy," boasted the boy. "Everybody knows that if you want to cool hot water down you add cold water to it, and when you put hot water into cold water it gets warmer. Hot water has a high temperature and cold water has a low temperature, and when you mix them you get something with an in-between temperature.
Everybody knows that."
While the boy and the girl were washing and talking they hadn’t noticed the small flash of light that winked on and off above the tap. They hadn’t noticed that when the flash had faded it had left behind a small, roundish red and black object that floated in the air, bouncing up and down ever so slightly. "Yes," said the object suddenly, "but what is temperature?"
The boy and the girl gave a start and stared at the object. The object's two, large catlike eyes stared back. A lob-sided, kindly smile underneath the eyes waited for the question it knew was coming. Now, in this situation, you may think that they would run, or scream, or perhaps just stare in shock with open mouths. However, the kindly smile and gentle cat-like eyes were strangely calming and somehow the children knew the object was friendly and wouldn't harm them. "Er, er, where, er, what, er, who are you?" said the girl.
"I'm Maxwell," said the object, "and you," he said, nodding slightly to the girl, "have asked a brilliant question. And you," he said, turning to the boy, "have made a good attempt to answer it." Maxwell paused a brief moment then continued, "But I ask again, what is temperature?"
The boy, confident, answered again, "It’s how hot or cold something is."
"Yes," said Maxell, "but what is it that makes a hot thing hot and a cold thing cold?"
The boy pondered but couldn’t think of an answer. He wanted to say its temperature, but that was the question they were being asked. The girl pondered but she also couldn’t think of an answer. "Oh, I wish I knew why," she said aloud.
"I'm not a genie," said Maxwell, "I don't grant wishes! But I can help. If you want to gain knowledge you’ve got to ask the right question. Ask the right question and I'll help you find a way to answer it."
The boy and the girl were silent for a short while, then, after seeing a twinkle in Maxwell’s eyes, the girl hesitantly repeated her question, "How does hot water know it’s hot, and cold water know it's cold, and how do they agree to be warm when you mix them?"
There was a flash. The boy and the girl blinked. When they opened their eyes they found themselves floating next to Maxwell, who had grown to be the same size as them. Or had they shrunk to his size? They looked around. They seemed to be surrounded by a sea blue. Were they underwater? How were they able to breathe?
"This is like cold water," said Maxwell suddenly. "Look carefully, what do you see?"
The boy and the girl looked around in amazement. "There's lots of little balls moving and jostling around and bashing into each other," said the boy.
"Some are moving really slow and they are deep blue," added the girl. "Some are moving a little faster and are a lighter blue. And there are some that are faster still and they are greenish."
"And," continued the boy, "sometimes a slow one is hit by a faster one which slows down the fast one and speeds up the slow one."
"Those things you see are called water particles. They are what water is made of," explained Maxwell. "I'm going to take you to hot water now. Tell me what you see."
There was another flash. When the children opened their eyes they found themselves in a sea of orange. They were again surrounded by small balls but this time they seemed to be moving much faster. "This is like a speeded-up version of cold water," said the boy. "Everything is zipping around."
"Yes," agreed the girl, but then she hesitated. "There are some really fast ones that are bright red, and many not so fast ones that are orange and yellow. But there are still some slow ones that are green and, look over there," she pointed, "there are a few that are very slow and blue."
"Excellent observation," said Maxwell. "So, what's the difference between hot and cold water?"
"In hot water," said the boy, "the particles are moving faster than they do in cold
water. But they still bash into each other and change each other's speed."
"But there can still be some slow ones though," added the girl. "Are water particles really that colour?" she asked as an after-thought.
Maxwell looked down for a second and smiled. "No," he said, "I added colour to make it easier for you to see the differences. A little like when you're cold you sit and shiver and go blue, and when you run around you get hot and go red. The colours aren't real and are, by the way, the opposite way around to how colours really go in hot things, like stars. But that's another adventure…" Maxwell trailed off, then started again brightly. "Watch," he said, "I'm going add some cold water to this hot water."
A plume of blue and greenish particles appeared from above them and mixed amongst the orange and red particles. "Look," said the girl, "the fast-moving particles are bashing into the slower ones and slowing down."
"And the slower ones are speeding up," added the boy.
As they watched the oranges and reds gradually faded to yellows and greens as they slowed down. And a number of blue ones faded to greens and yellows as they were speeded up. There were still a few very slow blue ones, and a few very fast orange ones but most were green to yellow and moving at a speed between fast and slow.
"Can you unmix the water particles back into hot and cold water?" asked the boy.
"That," said Maxwell with a frown, "is an entirely different problem." He turned to them and said, "it's time to go back now but remember, ask the right question and I'll help you find an answer." Then, after a short pause added, "If I can!" He winked and smiled, and, in a flash, he was gone and the boy and the girl were back at the sink.
"What's taking you two so long?" asked the parent from behind them.
"Oh nothing," said the boy, "We were just wondering why hot water is hot."
"And why cold water is cold," added the girl.