Scientific Endeavour - PDF

 SCIENTIFIC ENDEAVOUR 1. I Nature of Science - Science is the process of the natural world through observations & experimentation · - Scientific ideas are developed through reasoning....

 SCIENTIFIC ENDEAVOUR 1. I Nature of Science - Science is the process of the natural world through observations & experimentation · - Scientific ideas are developed through reasoning. Scientists evidence to support explanations about how the world works - use. A scientific theory well-substained explanation of aspect of the ~ is a some natural world incorporating facts laws inferences and well-tested hypotheses , , ,. Science is the process of identifying patterns in nature and developing - explanations of how and why those patterns exist. - Scientists use experimentation and careful observation to collect evidence to explanations. support those 1 2. Lab Safety and Apparatus 1. 2 1. Safe Practices in Science 1. 2 2. Hazard Symbols - Found on containers of chemicals to indicate the potential hazard it possesses. Harmful/Irritant Toxic chemicals Limit contact with chemical keep food and drink - -. away - May cause allergic reactions when in from handling areas. contact with skin , eyes etc. - Wear protective equipment. - Wash hands after handling chemicals. - Wash hands after handling chemicals. Corrosive Flammable - Avoid skin contact. - keep away from sources - Wash hands after handling chemicals. of fire. Explosives Toxic to aquatic life - keep away from sources of - Avoid release to the fire. environment. - Ensure proper disposal. Carcinogenic Cancer- Gases under pressure causing Compressed liquefied - , - Wear protective year. or dissolved gas under - Minimize contact with chemical.. pressure Do not inhale any vapour/fumes. keep away from heat. - - Radioactive Biohazard - Wear protective year. - Wash hands after Minimize contact with the handling chemicals. - chemical. - Wear protective year. Separate the radioactives Ensure proper disposal. - - from non-radioactives.  1 2 3.. Common Laboratory Apparatus 1 Bunsen Burner Tripod stand heat - For heating substances. - Support the apparatus during heating. Retort stand Wire Gauze - Support the apparatus - Used with tripod stand to during experiments. support apparatus during heating. a) Test tube Beaker b) Boiling tube - Contain larger amounts of Contain small amounts liquids/chemicals for heating - prevents liquid from spilling of substances for heating or mixing. or mixing. - Comes in various capacities. To heat small amounts of - substances. Gas jar Conical flask - Used for collection of - Used to hold liquids or large volumes of gases. chemicals. - Suitable for swirling-involved reactions reduced spillage. , Measuring cylinder Syringe - Measure a volume of - Used for measuring small liquid. volumes of liquids or gas. - mes in various capacities - Comes in various sizes.  Burette Pipette - Used for dispensing precise - Used to measure accurately volumes of liquids. fixed volumes of liquids. - Smallest division up to 0 I cm. - * Comes in various e.. g 20 Oml , 25 Omb.. capacities. Evaporating Dish Filter funnel - Evaporate a liquid from a - Used to transfer liquids solution by heating. into apparatus with small opening. Glass rod - Support filter paper when Used for stirring reacting carrying out filtration -. mixtures. Test tube holder Test tube rack - Used to hold a test-tube Used for holding test-tubes boiling tube while being - before/after they are used. heated. * Draw a filtration set-up Dropper 1 filter funnel filter paper. filter funnel - Used to transfer very small 2. beaker [ I amounts of liquids/drops i. retort 3 stand E beaker from one container to another. 4. filter funnel 1. 2 4 Bunsen Burner. 1 2.. 4. Parts of a Bunsen Burner # burner to mix with the gas. jet Allow the gas and air to mix. 1.2.4 2. Safety Precautions 1. Wear goggles when doing heating experiments.. 2 Ensure that there are no flammable items near the flame.. Close air hole before 3 lighting to prevent string. When not the flame , either the flame to burn at the gas jet using 4 , making the barrel very hot. a) turn off the gas supply b) close the air hole and lower gas supply 1 2 4 3... Types of Flames Luminous flame Non-Luminous flame - Obtained when air hole is closed - Obtained when air hole is opened (more incomplete combustion (more complete combustion) Pale light blue in colour Orange colour in - - - Unsteady Flickering - Steady Quiet flame Noisy flame - - Less hot (300 gentle heating) strong heating) ° Hotter flame (700 ° - C - C , , Gives off a lot of smoke (lots of soot) Gives off little smoke (little soot produced) - - 1.3 How Do We Practice Science?. 1 The Scientific Method 1. 3 - The Scientific Method is a sequence of steps procedure that leads an individual through the process of solving a problem. 1 Observation of. phenomenon. Data 6 Analysis observations and format it. - Observe your subject and record everything - Record the data + about it using your 5 senses. - Calculatingthe average for further analysis to support your hypothesis may be necessary.. State the question 2 - The trend or relationship between the variables can also be determined based on the data obtained. - Propose a research question regarding what - you want to find. out about.Conclusion 7 Based on the data analysis , conclude whether. 3 Conducting research - to accept or reject your hypothesis. - Conduct background research , write down your sources , cite your references. - Interview experts on the topic. - 4. Form a hypothesis - Hypothesis : a tentative testable , explanation. - Written in terms of cause and effect - Includes the independent and dependent variable. eg. When the temperature of water is higher, the sugar takes a shorter time to dissolve. X Temperature of water affects dissolving a sugar. experiment 5. Design an - Identify the independent dependent and constant variables. , - Choose suitable apparatus and materials for the experiment. - Decide how to record the observations or measurements. - Write the procedure to describe how you will conduct the experiment. be set up the apparatus will Include diagrams of how. - 1 3 1 1... Identifying Variables 1. Independent Variable. 2 Dependent Variable - Changed variable - - Measured variable. - To ensure a fair experiment , there should be - Depends on the independent variable. only one independent variable - Any change in the results be attributed determine the effect of. Experiment can - to eg to the independent variable. bio-fertiliser X on plant growth. hypo When fertilizer'x'. is used , the plant is able. Controlled Variable 3 to grow taller. - To be kept constant. inde. Addition of fertilizer 'X' Should be stated to the fairness Height of the plant after 1 month. ensure - depe. of the experiment. cont Volume of water used for watering. plants, amount of sunlight plant is exposed to. 1 3 1 2. -. Observation us Inference - Observations are made using our own senses or using scientific tools. - Inferences are ideas or conclusions based on what you have observed or already know. 1 4 Measurements. 1 4 1.. Physical Quantities & SI Units magnitude - A Physical quantity is quantity that can a. be measured eg 10 5 cm unit It consists of numerical magnitude and unit... - a a - Standard conventions are used for effective communication of scientific ideas. International System of Units (SI Units) -> inch feet yard , , Metric System > milimetre - , centimetre metre , - Physical quantities can be divided into base quantities and derived quantities. 1. Base quantities length-> , mass , time , etc. 2. Derived quantities > speed (length=time) - 1. Base quantities Physical Quantities Base Derived quantities quantities - length - area - mass - volume -time - density. Derived quantities 2 - temperature - speed - acceleration Powers of Ten https://youtu.be/0fKBhvDjuy0 1.4 2 Prefixes. Cell Size and Scale https://learn.genetics.utah.edu/content/cells/scale/ - Instead of writing long number with many zeros a , we can use prefixes. 1.4. 2 1 Unit Conversions. 1.Convert the unit given to the base unit.. Convert the base unit to the unit in the 2 question. litre(e) 1000 + me Im = 10dm = 100cm Idm = 10 cne 13dm3 = 1000 cm3 Idm3 = 1000 cm3 1. 4 3. Significant Figures Significant figures important because they tell us - are how good the data we are using are Rules for determining Significant Figures : 1. All non-zero digits are significant. 2. Any zeroes after non-zero digits are significant.. Zeroes before 3 non-zero digits are not significant. 1 4 4.. Measurement of Length 1 4 4 1 SI Unit and Instruments... The SI unit for length is the metre (m) - The metre rule measure and vernier calipers instruments used to tape are common measure - , lengths. - When measuring length use an instrument suitable for the , size of length to be measured that would give the highest precision. Understanding the of instrument. precision an - Precision = smallest measurement it can measure. measurement it has to be recorded instrument. When recording according to the precision of the - a ,..4 2 1 4. Precautions using Measuring Tape MetreRule (i) To prevent zero error : Measure from the 1 Ocm mark and then subtract from the. 1 O cm. reading. (ii) To prevent parallax error : The eye must be positioned vertically above and perpendicular to the mark to be read when taking the readings. 1.4.4 3 Vernier. Calipers Has precision of 0 Ol cm - a.. Useful formeasuring both the internal and external diameters of objects -. - Consists of a main scale and a sliding vernier scale. - Outside jaws for measuring external diameters of objects , inside jaws for internal diameters of containers and a depth bar for the depth of a , container. #IIIII 1 45.. Measurement of Temperature 1.4 5.. 1 SI Unit and Instrument - SI unit of temp , is the Kelvin (k). - The degree Celsius ° , is another C common unit used. , - The thermometer is used to measure temperature. Types of thermometer : 9) Liquid-in-glass thermometer b) Other types of thermometers · Commonly used in the lab. The liquid in the thermometer is mainly alcohol. · The liquid expands contracts as the temperature and changes , and the length of the thread measures the temperature. ° o Precision : 0. 5 C 1. 4 6 Measurement of Time. 1. 4 6 1 SI Unit and Instrument.. - The SI unit for time is the second(s). - The stopwatch is used to measure short time intervals. Types Stopwatches : of 9) Analogue stopwatch b) Digital stopwatch * Reading the digital stopwatch · Precision : 10 Is. · Precision : 10. OIS. 1. 4 7. Measurement of mass 1. 4 7 1 SI Unit.. and Instrument - TheSl Unit of kilogram (kg). mass is - Precision : 0 Olg.. * The gram (g) is more frequently used - The electronic balance is used to measure mass. Electronic Balance - Used to measure mass but actually measures , weight and electronically converts the value to mass. Steps for use : 1. Switch on the Power. * Difference between mass and weight. Press TARE' to 2 zero the scale.. Place 3 object to be weighed on the pan. * 4 Close. plastic doors. https://youtu.be/Y8-T8RouhPA. Read off the 5 display when it has stabilised 1 4 8 Measurement of Volume.. 1 4 8 1 SI... Unit 100 cm = Im - The Sl unit of volume is the cubic metre (m3) (100cm)3 (1m)3 = 1003 cm3 = Im3 - Other common units of volume are : 100cm = 10dm = Im · cubic centimeter (cm3) Cubic decimeter · (dm3) o litre (e) · millimetre (me) 1 4 8..2. Measuring Volume of solids - For solid objects with regular shapes , their volumes can be calculated with a formula. (fig. a) Fig. b fig. a - For solids with irregular shapes the displacement method can be used. , - A measuring cylinder is partially filled with water and the object is added to it. - The difference in the volume of water is the volume of the object. (fig. d) 1 4 8 3... Measuring Volume of Liquids a) Beaker 6) Measuring cylinder - Has different sizes and capacities. - Has different sizes and capacities. - Least accurate apparatus to measure - More accurate then a beaker. volumes. - Precision : 0. 2 cm3 to k cm3 (dependent on - Markings are far apart, used to measure cylinder size) volumes. approximate - Readings recorded to whole numbers.