Introduction to Science
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1. Science relates to phenomena in the natural world and enables technological development that benefits humanity. 2. It involves identifying problems, forming hypotheses, planning experiments, collecting and analyzing data, and reporting conclusions. 3. Scientists use various instruments and follow standardized measurement systems to study topics like health, transportation, and communication.
Introduction to Science
- 2. MEANING OF science Science is a knowledge that relates to the world around us RELATED PHENOMENA Parrot is able to fly Chameleon changes its Reproduction Ice melting skin color
- 3. Importance of science Science enables the development of new technologies to benefit mankind. FIELDS OF DEVELOPMENT Health Transportation Communication
- 4. Career in the science field Scientists Nurses Doctors Engineers
- 5. HAZARDOUS symbols Symbol Symbol Flammable Corrosive • Burns easily • May destroy living • Examples: alcohol, tissues on contact petrol, kerosene & • Examples: bromine, ether concentrated acids and alkali Irritant Poisonous • Can cause rashes and • Can cause harm or discomfort to the skin death if in contact • Examples: bromine, with skin, swallowed sulphur dioxide and or inhaled ammonia • Examples: mercury Explosive Radioactive • Explode easily • Releases radiation • Examples: sodium and • Examples: uranium, potassium radium and plutonium
- 6. Laboratory apparatus Test tubes Beaker Measuring cylinder Pipette • To hold small • To hold liquid • To measure the • To measure fixed quantities of volume of a liquid amount of volume liquids of a liquid. Filter funnel Bunsen burner Tripod stand Flask • To divert liquids • To heat things up • To support beaker • To hold liquids into a container in the laboratory or flask while such as conical heating flask or beaker
- 7. Evaporating dish Wire gauze Thermometer Retort stand & clamp • To evaporate • To spread out the • To measure • To hold apparatus liquids heat of the flame temperature at different heights eventually Burette Tube rack Stopwatch Pestle and mortar • To measure • To place test tubes • To record time • To crush solid into volume of a liquid powder accurately to 0.1cm3
- 8. Cork and stopper Spatula Glass rod Dropper • To close the mouth • To transfer solid • To stir liquids in a • To transfer small of test tubes and chemicals container amount of liquid flasks Filter paper Test tube tolder Crucible with lid Crucible tongs • Used together • To hold the test • To contain solids • To hold hot with a filter funnel tubes when it is that can be heated crucible and lids to separate solid being heated directly without from liquids using wire gauze
- 9. Steps in scientific investigation ❶ Identifying a problem ❷ Forming a hypothesis ❸ Planning the experiment ❹ Controlling variables ❺ Carrying out investigation ❻ Reporting
- 10. ❶ Identifying a problem • Arise from a desire to know what happens in our surroundings. • Examples: - Why do birds fly but not ostrich? - Why do cactus able to grow on a deserted land with no water available? ❷ Forming a hypothesis • A hypothesis is an early idea or explanation for the phenomena that we observe. • A hypothesis can only be accepted or proven true after going through experiments. If the hypothesis is not true, a new hypothesis has to be formed.
- 11. ❸ Planning the experiment • A list of material and apparatus required and the way they should be carry out are made before an experiment can begin. • Moreover, we need to determine the way to collect, analyze and interpret the data obtained from the experiments.
- 12. ❹ Controlling variables • Variables are situations and factors that are controlled and change in an investigation. • Types of variables: (a) A variable that is kept constant - variables that are kept constant or fixed (b) A variable that is manipulated (changed) - variables that are used to test the hypothesis (c) A variable that responds - results are collected from the variables that are changed when testing a hypothesis
- 13. ❺ Carrying out investigation • Steps that are to be followed: (1) Collecting data - all data are observed and measured accurately (2) Analyzing and interpreting data - the data is then presented in a table or chart - interpretation is made from the table or chart (3) Making conclusions - an accurate statement to describe the problems identified throughout the experiment - determine whether to accept or reject the hypothesis
- 14. ❻ Reporting Title/Aim: Hypothesis: • A report is made after conducting a scientific Variables: (a) Constant experiment based on (b) Manipulated (c) Responds the format shown: Material/apparatus: Procedure: Results/Observations: Discussion: Conclusion:
- 15. Physical quantities and units • Physical quantities are used to measure values of certain aspects (length, mass, time) • The International System of Units (SI) is used as a standard unit by scientists around the world. • Examples: Physical Physical SI unit quantity Quantity Length metre (m) Example: Length = 10 m Time seconds (s) Mass kilogram (kg) Value Unit Temperature kelvin (K)
- 16. Prefixes • Prefix is used to record readings that are too big or too small Prefix Symbol Actual value of the Value of the symbol symbol in standard form tera T 1 000 000 000 000 X 1012 giga G 1 000 000 000 X 109 mega M 1 000 000 X 106 kilo k 1 000 X 103 deci d 0.1 X 10-1 centi c 0.01 X 10-2 milli m 0.001 X 10-3 micro μ 0.000 001 X 10-6 nano n 0.000 000 001 X 10-9 pico p 0.000 000 000 001 X 10-12
- 17. Change to prefix form Change to standard form (a) 2 000 m to km (c) 4.5 mm to m 2 000 m = 2 X 103 m = 2 km 4.5 mm = 4.5 X 10-3 m Physical Standard Prefix Prefix Standard quantity form form form form (b) 0.05 m to cm (d) 8.5 μg to g 0.05 m = 5.0 X 10-2 m = 5.0 cm 8.5 μg = 8.5 X 10-6 g Physical Standard Prefix Prefix Standard quantity form form form form
- 18. MEASUREMENT OF MASS Mass Weight A measure of the Definition A measure of the amount of matter in gravitational force on an object an object. Always constant, no Does it Depending on where matter the location. change with the object is in location? relation to the earth kilogram (kg) Unit used Newton (N) gram (g) Electronic Measured Spring balance with scale
- 19. MEASUREMENT OF LENGTH • Length is the distance between two points and is TOOLS TO MEASURE measured in the unit of: Measuring Calipers 1 cm = 10 mm tapes 1 m = 100 cm 1 km = 1 000 m External Internal calipers calipers Correct way of reading measurement
- 20. MEASURING LENGTH Straight line Curved line Diameter Measured by Measured by measuring Internal External thread and tapes: ruler: Measured Measured by internal by external caliper caliper External Internal caliper Thread Curved line caliper
- 21. MEASUREMENT OF AREA • Area is the total surface or space occupies by an object Area = length X width MEASURING AREA Regular shape Irregular shape 1 cm 1 cm Area = 3 cm X 3 cm Estimated area = 12 cm2 = 12 cm2
- 22. MEASUREMENT OF volume • Volume is the total MEASURING LIQUIDS space occupied by an object & the units are: Fixed volume Variable volume 1 ml = 1 cm3 Used to measure Used to measure 1 l = 1 000 ml volume accurately to any volume ranging = 1 000 cm3 5 ml, 10ml, 25 ml, from 0.1 cm3 to 50ml and 100ml 100 cm3 Correct way of reading measurement WRONG volumetric measuring CORRECT pipette flask cylinder burette WRONG
- 23. MEASURING SOLID Regular Shape Irregular Shape Using measuring Using eureka cylinder can Volume of the box = length X width X height = 2 cm X 1 cm X 2 cm = 4 cm3 Volume of stone Volume of stone = volume after – = volume being volume before displaced from = 40 cm3 – 30 cm3 the beaker = 10 cm3 = 30 cm3