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Make 50 Wild and Wacky (but Useful!) Contraptions
Building a Contraption
Always remember that, broadly speaking, there are only two things that go into making a great contraption....
First, it has to be able to do something. Whether it's catching a mouse, flipping a domino, or switching off a light, your contraption should be able to fulfill some sort of meaningful (if absurdly basic) task. Second, it has to do it in style. This means unexpected twists, a sense of humor, and—above all else—far greater complexity than is necessary. After all, the point of these contraptions is that they're designed to make a simple task as complicated as possible, otherwise you may just as well go out and buy a real mousetrap, apple corer, or light switch. If you can look at your design and honestly say that it fulfills both of these criteria, then you're well on your way.
Getting it right
Before you start work, remember the three Ps: Preparation, Planning, and Prototype. Start by working your design out on paper, then rough it out in real life in sections, and only then start to make the finished device. It's always a good idea to start at the cud, with whatever it is that you want to do—popular actions include pouring cereal into a bowl, squeezing toothpaste onto a toothbrush, unscrewing the lid of a jar, turning the page of a hook, and opening a window blind.
Although it sounds back-to-front, it's important that you build from the finish backward. If, for example, a cage needs to be knocked over a "mouse," what's going to do the knocking? And what's going to cause it? Are there any otherways to spring the trap, and would any of them be more dramatic, or effective, or funny? Sometimes you suspect that some Hollywood films start life like this: with a great ending, and the hope that the rest will fall into place. You need to think the same way.
The great thing about designing contraptions is the way that you can change things around—often at the last minute—to improve the design. As long as there's enough variation in each of the individual sections, you can mix them up until you find out what makes the most exciting contraption.
When you were in school, you might have thought that the only point to Sir Isaac Newton was to make your life miserable; alternatively, you could have thought he was the greatest genius until the man who invented the cell phone with a built-in MP3 player.
What we owe Newton, however, is nothing less than the science of classical mechanics, which neatly describes the motion of objects through space in a series of laws and mathematical equations. This is precisely the science that you'll be using when you're building and operating your own contraptions.
Sir Isaac Does Fruit
Sir Isaac Newton (1642-1727) is famous for his apple—the clue, so the legend has it, to the secrets of gravity. But Newton is far more significant than his experiences with ballistic fruit. In his Philosophiae Naturalis Principia Mathematica (Mathematical Principles of Natural 1 Philosophy) of 1687 he outlined the J three laws of motion that describe how all objects move (see box) and the law of universal gravitation. The "Principia" became the foundation of the science of classical mechanics, which in turn remains the basis for the branches of modern physics.
Classical mechanics concerns itself with different types of motion at the macroscopic scale, that is, the world we can see, feel, and touch. When dealing with the infinitely small, and infinitely fast, you need quite different forms of physics, but when planning your contraptions, consider using different forms of motion to achieve more varied and interesting effects. Here are the main types of motion described by classical mechanics:
Translational: motion by which a body shifts from one point in space to another (for example, the motion of a projectile).
Rotational: motion by which a body changes orientation with respect to other bodies without changing position (for example, the motion of a spinning top).
Oscillatory: motion that continually repeats in time with a fixed period (for example, the motion of a pendulum).
Circular: motion by which a body executes a circular orbit about another fixed body (for example, the orbit of a planet around a sun).
A Matter of Words
In describing motion, classical mechanics employs mathematical equations, which are beyond the scope of this book to explain in detail. However, classical mechanics also uses a very precise vocabulary of terms that are often confused with more general terms. In this section, we'll look at the concepts of displacement, velocity, acceleration, and mass, which in common usage are often confused with distance, speed, - and weight.
Out of Place
Displacement shouldn't be confused with distance. For I example, displacement doesn't indicate how many miles a ear has traveled along a winding road, but how far it has moved relative to a fixed reference point of origin along a vector (a line of direction).
Fast and Furious
In colloquial English, speed is often used to mean velocity and acceleration, which are the two key concepts of motion. Velocity is the change in an object's position (its displacement) over time. Velocity can be either positive or negative, depending on the direction of motion. The conventional definition of speed is that it's the magnitude of velocity, and object can't have a negative speed. Acceleration is the rate of change in the velocity over time. It can arise from a change with time of the magnitude of the velocity, or of the direction of the velocity, or both.
The terms mass and weight are often confused. However, in classical mechanics their meanings are quite different. An object's mass is a measure of its inertia; that is, its resistance to deviating from uniform straight-line motion under the influence of an external force. Weight is simply the force exacted by the gravity of the earth with which the earth attracts an object.Make 50 Wild and Wacky (but Useful!) Contraptions. Copyright � by Robert Brandt. Reprinted by permission of HarperCollins Publishers, Inc. All rights reserved. Available now wherever books are sold. <%END%>