Free The Prometheus Project by Douglas E. Richards Page B

location of the force-field without activating it.
    Minutes later they exited the tram and climbed one of the orange trees. They were in luck! A stream was only a few hundred yards away, winding its way through the woods.
    Using the holographic controls they drove toward the stream. The tram slid forward as though on a sheet of ice, even over rough and uneven terrain. They passed several small alien animals but nothing that looked threatening.
    They parked the tram and walked eagerly to the stream. Ryan bent over and put a hand in. The water was cool and nothing had ever looked more refreshing. He smelled it carefully. It had no odor of any kind. This was a good sign. Ryan cupped his hands and prepared to take a sip.
    “Shouldn’t we test it first?” said Regan. “To be sure it really is water. We’re not on Earth, after all.”
    “I already tested it the only way I know how. It feels and smells exactly like water,” said Ryan.
    “And it probably is. But what if it turns out to be some strange liquid that doesn’t exist on Earth? For all we know, a single drop might kill us.”
    Ryan looked at his hands nervously and then quickly wiped them dry on his pants. “Okay. That’s a good point,” he acknowledged. His forehead creased in thought. “So how else do you test for water?”
    “I have no idea.”
    “But you were the one who just said we should test it.”
    “I know,” she said. “Since I came up with the idea, I thought you could come up with the test,” she added, smiling.
    Ryan laughed. “Okay,” he said. “I accept the challenge.” He thought for a moment. “I guess the key is to think of properties of water that are unique.”
    “Are there any?”
    “Yeah. I know I learned that water is pretty remarkable, either from Mom or at school. Give me a minute to remember.” He strained as hard as he could until some of the information finally began to come back to him. “Okay,” he began. “Here’s a unique property. Things expand when they get warmer and contract when they get colder. Like the liquid in a thermometer. So if you freeze a liquid solid, it contracts: it takes up less space. But water does the opposite,” he added triumphantly. “Water actually expands when it’s frozen.”
    Very interesting, thought Regan. She remembered leaving a bottle of water in the freezer a few months earlier. Sure enough, when it had turned to ice it had expanded and broken the bottle. She hadn’t really thought about it before, but he was right.
    “And because water expands when it freezes,” continued her brother, “ice is less dense than water, so it’s able to float on water. This floating thing is very unique to water also.”
    “So what are you saying, that if you made ice-cubes out of gasoline and put them in a glass of gasoline, the cubes would sink to the bottom?”
    “Exactly,” he said. He smiled as an image popped into his head of a woman in a fancy dress, sipping a glass of cold gasoline like it was lemonade. “I remember Mom telling me that this was a very important property of water. Because ice floats, in the winter a lake or river becomes frozen on top, protecting the water beneath from freezing also. If ice didn’t float, the surface would keep freezing and sinking to the bottom until the entire lake or river ended up as a gigantic cube of ice, killing all the fish.”
    Regan listened in fascination. There had to be a way to use this information. And then it hit her! Of course . “You did it Ryan. We have our test. All we have to do is turn some of this stream ‘water’ into ice and see if it floats in the stream.”
    “Good plan, Regan. But unless you happen to have a freezer with you it doesn’t help us.”
    Regan grinned broadly. “You’ve been in California too long, Ryan,” she teased. “It’s true that in San Diego the only way to freeze water is with a freezer. But in other parts of the country there is another way— leave it outside during the winter