วันเสาร์ที่ 12 มิถุนายน พ.ศ. 2553

The Need for Tools

Humans are truly amazing creatures. Compared with many other animals on the planet, it might seem as if we are at a serious disadvantage. Ostriches can outrun us, elephants can out-pull us, and lions can rip us to pieces. Bats have better hearing, eagles have better eyesight, and even mosquitoes and wasps pack more of a sting. Despite all these limitations, we’ve done pretty well as a species. Th at’s because unlike most other animals, humans can make tools. Using tools, humans have molded and shaped the world. Tools also have allowed us to adapt to just about every environment on the planet. Th e truth of the matter is that without tools, humans probably would have become extinct a very long time ago.

When people hear the word tool, they usually think of objects such as hammers, screwdrivers, or even chain saws. Tools aren’t just for building, though. In fact, most of us can’t go more than a few minutes without using some type of tool. When you brush your teeth, you use a tool. When you eat your cereal or butter a bagel, you are using tools. Even pencils and pens are specialized tools. In the most general sense, a tool can be any device used to get a job done or make a task easier. Some tools, such as a sewing needle or a wrench, are simple. Th ey require only the force of a human hand to make them work. Other tools, such as a table saw or a drill press, are complex. Th ey have many moving parts, and motors or engines power them.

These days, people have an incredible variety of tools at their disposal to do all sorts of diff erent jobs. If you take a trip to a local hardware store or home improvement store, you can find hundreds of different devices for doing all sorts of tasks. Some tools, such as a pair of pliers, are versatile: They can be used for many different jobs. Others, such as a torque wrench, are designed for only one specific task. Regardless of a tool’s size, use, or complexity, our ability to make and use tools has been the driving force behind human evolution. Tools have taken us from being simple nomadic scavengers to space explorers and movers of mountains.

No one knows for certain how long humans have been making and using tools, but many scientists believe that we’ve been at it for at least 2.5 million years. We don’t have an exact date because we’re not sure what the first tools looked like. In addition, the historical record from this time is very spotty, so just finding true artifacts is very difficult.

Some of the earliest tools were made out of stone. They look similar to rocks that you might find lying around on the ground. In fact, unless you were trained in identifying tools, you would probably walk right over these rocks without even noticing them. Many scientists believe that before making tools, early humans began using stones for different tasks. Small rounded rocks were used to crack open nuts or break animal bones to get the marrow out. Rocks with sharp edges were used to cut through animal skins and tough plant material, such as vines.

Over time, humans discovered that they didn’t have to waste time looking for stones with the right shapes. Instead, they found that they could use one stone to chip away at another stone and shape it to fit the job. They learned that they could make tools to help them in their everyday lives.