Lifting a horse with your 1 finger doesn’t make sense. Yes, it doesn’t make sense without using tools. But what tool serves to lift a horse with only one finger. Archimedes said “If I have a place to stand and a lever long enough, I can lift the earth”.
aksiografi.com – Science is a system of knowledge about the nature of the things in the universe (Earth and all natural objects in space regarded as a whole). Astronomy is the study of celestial bodies (natural things in the sky, such as stars, suns, moons, and planets). Biology is the study of organisms (living things, such as plants and animals). Chemistry is the study of the materials that substances are made of and how they change and combine. Earth science is the study of the Earth. Physics is the study of energy and matter and how they interact. Energy is the ability to cause motion, and matter is anything that can be moved. Matter takes up space and has mass (an amount of material).
People began thinking about and doing science thousands of years ago, before they even developed a system of writing. So there is no written record of the first investigations. But some of the earliest drawings indicate observations of the natural world, such as the rising and setting of the Sun, phases of the Moon, and fire. (See chapter 7 for more on phases.) Like many of today’s scientific discoveries, the “discovery” of fire was serendipitous, which means it was accidental. The first observed fire was most likely created by lightning. One can only guess at the observations made at the time, but getting burned was probably one of them. Fire was one of humans’ most important early discoveries. It changed the way people lived and the way societies developed. With fire, not only could people stay warm, but they could also cook and keep their food longer.
The ancient people who made the greatest contributions to Western science were the Greeks. Greek philosophers (people who study the meaning of life, problems of right and wrong, and how we know things) made many observations of the natural world and developed theories (ideas) to explain things they saw. Pythagoras of Samos (c.580–c.500 B.C.), a Greek philosopher and religious leader, was responsible for important developments in the history of mathematics and astronomy. Aristotle (384–322 B.C.) was the most influential philosopher in the history of Western thought. Centuries after his death, the writings of Aristotle were considered the truth by the Christian church, and to disagree with his ideas was a crime punishable by imprisonment or death. The study of the natural sciences was dominated by Aristotle until early modern times. While Aristotle and most other Greek scholars were thinkers, some, such as the Greek mathematician Archimedes (c.298–212 B.C.), also performed experiments.
In the past as well as now, scientific advancements occurred out of the need to solve problems. One common problem was the movement of heavy objects, such as large rocks. A machine is a tool used to make it easier to move things. One of the first simple machines used to move a load was the lever. A lever is any rigid bar, such as a tree limb, that turns about a support called a fulcrum. The lever was used for thousands of years before Archimedes explained how it worked. From his investigations, Archimedes determined that if you had a long enough lever you could lift anything, even a horse by pushing down on one end of the lever with one finger. The problem, of course, is getting a lever strong enough and long enough, but in theory it is true, as you’ll see in the investigation that follows.
The demonstration of Nature School is to demonstrate a lever.
egg-size piece of modeling clay
1. Break the clay into four pieces as close to the same size as possible.
2. Mold the clay into four balls.
3. Lay the ruler on a table. Place one clay ball at one end of the ruler and two clay balls, one in front of the other, at the opposite end.
4. Lay the index card on the table and the fourth clay ball in the center of the card. The clay is a support.
5. Position the ruler on the clay support so that it balances. Make note of the length of the ruler on both sides of the clay support.
NOTE: If you have difficulty balancing the ruler, slightly flatten the top of the clay support.
From the point where the ruler balances, it is longer to the end with one clay ball than to the end with two clay balls.
The place where the ruler is supported by the clay represents a fulcrum, the point about which a lever (the ruler) turns. If equal weights were placed on opposite ends of a lever, the lever would balance with the fulcrum in the center. But if unequal weights were place on the ends of the lever, as in this investigation, the fulcrum would have to be closer to the heavier weight to balance the lever. The distance a weight is from the fulcrum is called the lever arm. When the fulcrum is not in the center of the lever, but is placed closer to one end, the result is two unequal lever arms, one short and the other long. It takes less weight on the long lever arm to bal ance a heavier weight on the short lever arm. Archimedes said that if he had a place to stand and a long enough lever, he could lift the Earth.
MORE FUN WITH BALANCE!
Make a balancing bee by copying or tracing the bee pattern on this page. Glue the pattern to stiff paper, such as poster board. When the glue has dried, cut out the bee.
Make two separate chains with three paper clips in each chain. Attach one chain to the end of each wing. Take a new pencil with a flat eraser and hold it vertically in one hand (eraser end up). Hold the bee horizontally in the other hand. Place the tip of the bee’s nose in the center of the eraser and release the bee. The bee stands on its nose. If it leans to one side, adjust the position of the paper clip chains. This will change the length of the lever arms, the distance the chains are from the fulcrum (the bee’s nose). As with the ruler in the original investigation, the length of the lever arms affects how the bee balances.
Hann, Judith. How Science Works. Pleasantville, N.Y.: The Reader’s Digest Association, 1991. Interesting facts and activities about levers and other science topics.
Richards, Roy. 101 Science Tricks. New York: Sterling, 1990. Fun experiments about levers and other science topics with everyday materials.
VanCleave, Janice. Janice VanCleave’s Machines. New York: Wiley, 1993. Experiments about levers and other machines. Each chapter contains ideas that can be turned into awardwinning science fair projects.