Science. By Abigail Stivala.
What is science? • Science is a practical way of understanding the world and everything In it. • Make observations and measurements. • Try to explain their observations with theories. • Test their theories with experiments. • Make discoveries that lead to inventions that are important for society and the environment.
Penicillin. • A scientist called Alexander Fleming grew some bacteria ( germs ) in a dish. • Some mould from the air accidently landed in the dish and started to grow. Fleming observed that bacteria did not grow near the mould. His theory was the substance made by the mould killed the bacteria. To test his theory Fleming made a broth from the mould and experimented to see if it killed bacteria. It did.
Penicillin. • Fleming called the substance he discovered penicillin. It was an antibiotic. Ten years later two other scientist, Howard Florey and Ernest Chain, showed that penicillin could be swallowed to treat illness caused by bacteria. Antibiotics have saved million of lives.
The Branches of Science. • Biology is the study of living things.
The Branches of Science. • Physics is the science of matter, forces and energy. This includes movement, heat, light, sound, electricity and magnetism.
The Branches of Science. • Chemistry is the study of substances and reactions.
The Branches of Science. • Geology is the study of the soil and rocks from which the Earth is made.
Observations and investigating. • Scientist use their senses and scientific instruments to observe objects, living things or something that happens. For example, a biologist studying a leaf looks closely at its shape and colour.
Making measurements. • An ant is small but how small? A pyramid is tall but how tall? To make reliable observations that others can check, scientists make measurements with measuring instruments such as rulers, clocks and thermometers.
A fair test. • A good experiment must be a fair test of your ideas. To test the theory that plants need light to grow well, you could grow one plant in a box and one plant in the light. But you must water both plants to make the test fair. In a fair test everything – apart from the thing you are testing – is kept the same.
Recording observations. • A good scientist always records all his observations so that they are not forgotten and can be checked by others. He calls his records his data. When you do experiments, you should describe your method with words and sketches in your notebook. Note the date and time, and record any measurements in a table.
Safety in the laboratory. • To be science you cannot just study science from books, you must do experiments in the laboratory to test your ideas and make discoveries. • Practical work with scientific equipment makes science interesting and exiting, but there are potential dangers. A science laboratory can be a dangerous place if people do not take care while they do experiments. To stay safe, we must think about the things that can cause harm. Remember that:
Safety in the laboratory. • Electricity can kill. We should never use water and electricity together. • Sharp blades and pieces of broken material can cause cuts. • Heat can cause burns; Hot water can scald. Allow hot containers to cool before you move them. • Heavy objects can cause bruises if they fall.
Safety in the laboratory. • Loose outer clothing can catch apparatus and knock it off the bench. • People can fall over bags. An untidy laboratory can lead to accidents. Keep the floor tidy, and bags and coats out of the way. • Long hair must be tied back. • Heated substances can splash and cause burns or scalds. • Some chemicals are poisonous and some are irritants and could damage your eyesight. Never smell, taste or touch unless you know that it is safe.