•We want to know why and how all these thingshappen. We search for an answers. Thus, the study ofscience gives us answers.•Science is the systematic study of nature and how itaffects us and the environment.•The information produced from the study of science isknown as scientific knowledge.•Scientific knowledge develops as new scientificdiscoveries are discovered every day.
•Using scientific knowledge, we invent many usefuldevices such as light bulbs, telephones andcomputers. The application of scientific knowledgefor the use of mankind is called technology.•We use technology almost every aspect of lifethus making science part of our every day life.
Importance of Science•Science plays important roles in our daily life.a.Science helps us to understand ourselves.Knowing how our body works, helps us to takebetter care of our health.b.Science also helps us to understand ourenvironment. This helps us to improve thequality of our environment and conserve it forour future generation.c.Science makes our life more comfortable. Weinvent various machines to help us to work fasterand more efficiently.
Use and benefits of science in daily life In Homes•Facilities such as electricity and tap water make life easier andmore comfortable.•Various appliances such as washing machine, microwave ovenand vacuum help us to do our housework faster.
Communication•Communication is easier and faster with the use of television,telephone, mobile phone, facsimile and computer.•Global communication is now possible with the use ofcommunication satellites, e-mail and the internet.
Transportation•Transportation is easier, faster and more comfortable.•Modern public transports such as commuter trains and lightrail transit reduce congestion in cities.•The design of better roads and highways increases the safety ofusers.
Construction•Buildings and structures are now built with strong materialssuch as steel, concrete and reinforced glass.•Powerful machinery such as cranes, tractors and bulldozers areusually used in construction works.
Agriculture•Machines are used to carry out heavy and difficult taskssuch as ploughing and harvesting.•Plant breeding, new agricultural techniques, fertilizers andinsecticides contribute greatly in increasing the world’sagricultural products.
Medicine•More diseases can now be cured with the discoveries of newdrugs, vaccines, antibiotics and the invention of better surgerytechniques and equipment.•Diseases can be diagnosed and detected earlier with varioustests and devices such as X-ray machine and ultrasoundscanning device.
Careers in science•Science offers various career opportunitiesaccording to one’s area of interest.a.Doctor – a person has been trained in andpractises medicinal science.b. Veterinarian – an animal doctor.c. Pharmacist – a person who dispensesmedical drugs and advise their uses.
d. Engineer – a skilled person who designs, builds or maintains engines, buildings, bridges or roads.e. Architect – a person who design buildings and advises on their construction.f. Chemist – a person trained in chemistry.
•Science is divided into a number of areas of study:a. Biology – the study of life.b. Physics – the study of matter, energy, force and motion.c. Chemistry – the study of composition and chemical properties of substance.d. Astronomy – the study of planets and stars in the Earth.e. Geology – the study of rocks, minerals and the structure of the universe.f. Meteorology – the study of weather and climate.g. Biochemistry – the study of chemical process in living organisms.
Science Laboratory•The place where a scientist works is called laboratory.•Students carry out scientific investigations orexperiments during science lessons in sciencelaboratories.•There are rules and safety precautions that must befollowed by the students in order to avoid accidents.
Rules and Safety PrecautionsNever enter the laboratory unless a teacher ispresent.Do not eat, drink or taste chemicals.Always follow the teacher’s instructions.Never touch chemicals with your bare hands. Use aspatula.Read a label on a reagent bottle before using itscontent.Turn off the Bunsen burner after use.Do not pour back any unused chemical into its bottle
Do not throw solid wastes into the sink.Wash and keep all apparatus after use.Do not run or play in the laboratory.Do not test anything without the teacher’spermission.Report any breakages to the teacher.Keep the bench clean and tidy.
•We need to use apparatus to carry out experiments Test tube Boiling tube To hold a small amounts For heating small amounts of liquid or chemical. of liquid.
BeakerConical Flask Flat – BottomedFlaskTo hold bigger amounts of liquids or chemicals.
Measuring cylinderTo measure volume of Pipetteliquids. To measure a fixed volume of liquids.
BuretteTo measure small volumes Retort standof liquid accurately. To hold or support apparatus.
Filter funnelUsed together with a filter Bunsen burnerpaper to filter mixtures ofsolids and liquids. To provide a flame for heating.
Tripod standTo support apparatus Wire gauzeduring heating. To support apparatus and ensure even heating.
Evaporating dishTo hold liquids for Crucibleevaporating. To hold solids for strong heating.
Test tube holderTo hold a test tube during Spatulaheating. To transfer small amounts of liquids.
a. A Bunsen burner is used in the laboratory to heat substance.b. The Bunsen burner has an air – hole. The air – hole can be opened or closed by turning the collar.c. When the air – hole is opened, the Bunsen burner gives a blue flame. This is called a non – luminous flame. The flame is very hot because the gas is burned completely.d. When the air – hole is closed. The burner gives a yellow flame. This flame is easier to see and it is called luminous flame. This flame is less hot and produce a lot of black soot because the gas is not burned completely.
e. The correct way to light up a Bunsen burner isas follows:•Close the air – hole by turning the collar.•Hold a lighted match or a lighter at the top of thebarrel.•Turn on the gas slowly. A yellow or luminousflame will be obtained.•Open the air – hole to obtain a blue or non –luminous flame.
f. To avoid accidents when using a Bunseenburner, the following precautions should betaken.•Use a lighter or a match to light up a Bunsenburner instead of a burning paper.•We must light up the match before turning onthe gas.•When heating a test tube, hold the test tube atan angle of 45 degrees. Use a test – tube holderand do not point the mouth of the test tube toyourself of your friends.
•Do not heat flammable substances likealcohol directly.•When not using the Bunsen burnertemporarily, close the air – hole to obtainthe yellow flame because this flame iseasily seen. Remember to turn off the gasafter using the burner.
The correct way to hold a test tube during heating.
•Some substances in the laboratory arehazardous or dangerous.•Hazard warning symbols are placed on labelsof bottles or containers of hazardous substancesto show the danger of the substances.•As young scientists, you must be able torecognize the symbols and know how to handlethe substances properly.
Symbols Danger of Examples Handling substances techniques Explosive •Sodium, •Keep in •Easily potassium paraffin explodes •Concentrated •Avoid contact when mixed acids and with water with other alkalis •Keep away substance from other substances including water.
Flammable or •Organic •Keep awayinflammable solvents from fire or such as heat•Easily catchesfire and burns ethanol, sources. petrol or keroseneToxic / •Mercury, •Do notpoisonous chloroform, inhale, lead,•Causes death touch oror harm to the benzene, bromine, taste thebody if sodium substances.absorbedthrough the cyanide, •Keep in askin, swallowed hydrogen lockedor inhaled. sulphide cupboard.
Corrosive •Concentrated •Avoid acids and contact with•Causes damage alkalis, skin or eyes.to the skin or bromine, •Spill on bodyeyes upon hydrogen parts shouldcontact peroxide. be washed away quickly under running waterIrritant / harmful•Ammonia •Spill on body parts•Irritates causes solution, should be washes with a lot of water.(itchiness and chloroform,rashes) skin, dilute acidseyes and and alkalisrespiratorysystem
Radioactive •Uranium, •Keep in special plutonium, radium. lead containers.•Gives outradiation thatcan causecancer ordestroy bodilytissues.