• Science is the systematic study of nature and how it affects us and our environment.• Science can explain natural phenomena that happen in our environment.• How? – Through careful observations, studies and scientific investigations.
Environmentalist Archeologist Doctor Forensic technician Science teacher
VARIOUS FIELDS IN SCIENCE• Science covers a very wide area of study and is divided into various fields, such as: – Biology: the study of living things – Physics : the study of interaction of matter and energy – Chemistry : the study of composition and chemical properties of substances, their reactions and uses – Geology : the study of rocks and minerals – Astronomy : the study of the stars and planets – Meteorology : the study of weather and climate
• Wearing goggles• Carrying bottles by the body; not the neck
Bunsen burner Tripod stand and wire gauze Test tube Crucible
1. Identifying problem 2. Forming a hypothesis 3. Planning the experiment 4. Controlling the variables 5. Collecting data6. Analysing and interpreting data 7. Drawing a conclusion 8. Writing a report
2. Write down a report on Simple pendulum experiment.
• To investigate how the length of the pendulum string affect the time for 10 complete swings of the pendulum.• How the length of the pendulum string affect the time for 10 complete swings of the pendulum?
• If the length of the pendulum is longer, the time taken for 10 complete swing of the pendulum is longer.
• Manipulated (what to change) : the length of the pendulum• Responding (what is observed) : time taken for 10 complete swings• Constant (kept the same) : mass of the pendulum bob
• Pendulum bob, string/thread, retort stand and clamp, stop watch• Apparatus set-up:
1. Prepare the simple pendulum with a 10cm long thread.2. Pull the pendulum bob to one side, then release.3. Record the time taken for 10 complete oscillations in a table.4. Repeat the experiment using a simple pendulum of different lengths, e.g. 20cm, 30cm, 40cm and 50cm.5. Draw a graph showing the time taken versus length of pendulum for 10 complete oscillations.
1. A simple pendulum with a 10 cm long thread was prepared.2. The pendulum was pulled to one side, and then was released.3. The time taken for 10 complete oscillations was recorded in a table.4. The experiment was repeated using a simple pendulum with 20cm, 30cm, 40 and 50cm long.5. A graph showing the time taken versus length of pendulum for 10 complete oscillations was drawn.
• Graph of time taken for 10 complete oscillations versus length of simple pendulum.
From the graph, we can say that:1. The pendulum with a longer string takes longer time to oscillate than the pendulum with a shorter string.2. The time taken for the pendulum to make one complete oscillation will increase when the pendulum string is longer.
• From the results, the hypothesis is accepted .• The time taken for the simple pendulum to make one complete oscillation increases with the length of the pendulum.
• Measurement is important because: –It helps to describe things everyday; –It is a part of the scientific investigation process (e.g: simple pendulum experiment)
Can be measured Cannot be measuredHow far is your house to How beautiful a person the school? is?How long does you take How does a durian to finish your taste? homework? How hot is a glass of How soft a pillow is? water? How a flower smell?
• A physical quantity is something that can be measured.• There are five basic quantities: length, time, mass, temperature and electric current.• Measurement of physical quantities consist of two parts: – A number indicating value or how much; – A unit of measurement.
• Unit is a scale that helps you understand a particular measurement.• S.I units: International standard unit of measurement (Systeme International d’ Unites).
Allow us to analyse data and compare information easily and more accurately;No confusion because there is specific symbols for each unit;Allow us to solve problems related to measurement.
Physical SI units Symbols Definition quantitiesLength A measurement of how long Metre m something from one point to anotherMass A measurement of how much matter Kilogram kg there is in an objectTime A measurement of the interval Second s between two eventsTemperature A measurement of the warmness or Kelvin K coldness in any objectElectric current A measurement of the rate flow of Ampere A electric charges through a circuit
• Prefixes are added to units like meter and gram when we need to state values that are too small or too large. Numerical Prefix Multiplier Symbol value Micro X 10-6 µ 0.000001 Milli X 10-3 m 0.001 Centi X 10-2 c 0.01 Kilo X 103 k 1000 Mega X 106 M 1000000
• The weight of an object is the pull of the Earth (force of gravity) on the object.• The S.I unit of weight is Newton (N).• The weight of any object depends on the gravitational force.• The weight of an object is obtained using a spring balance or compression spring balance.
• The mass of an object is the quantity of matter in the object.• The S.I. unit of mass is kilogram (kg).• The mass of an object can be obtained using a triple beam balance or lever balance.
It is the amount of It is the gravitational matter in an object. pull on an object. Its value varies from Its value is fixed. place to place. Unit: kilogram (kg) Unit: Newton (N)Measured using beam Measured using spring balance or lever balance or weighing balance. balance.
• Tools: ruler, metre rule, measuring tape• Measuring the length of a straight line: – Using metre rule or a ruler – Correct position of eye (to avoid parallax error)
• Measuring the length of a curve: – Using a ruler and a piece of thread • A knot is tied at the end of a thread • The thread is stretched along the curve carefully • Make a mark at the end of the curve • Stretch the thread along the ruler to obtain the length – Using an opisometer
• Measuring the diameter of a spherical object: – Using two wooden blocks and a ruler – Using a set-square and a ruler
• Measuring the diameter of an object: – The external diameter is measured using external calipers and a ruler – The internal diameter is measured using internal caliper and a ruler.
• Measuring the thickness of an object: – The thickness of a piece of paper can be determined by measuring the thickness of a stack of papers and dividing the value of number of sheets of paper. Thicknessof a stack of paperThicknessof a single sheet Number of sheets
– The thickness of a glass tube can be measured by taking the difference between its external and internal diameter. External diameter - internal diameterThicknessof glass 2
• Area is the total surface covered by an object.• The SI unit is square metre (m2).• Regular-shaped areas can be calculated using Mathematical formulae.• Irregular-shaped areas can be estimated by using a graph paper.
• Using graph paper: – Trace the object on the graph paper. – Estimate the area by counting the number of full squares, half full squares and more than half full squares (tick the squares) – Area of the object is estimated by multiplying the number of squares with the area of one square. – The area can be estimated more accurately with smaller squares.
• Volume of an object is the total space occupied by the object.• The SI unit is cubic metre (m3).• It also can be measured in millilitre (ml).• The apparatus: measuring cylinder, burette and pipette. 1 ml = 1 cm3 1 l = 1000 cm3= 1000 ml 1 m3= 1 000 000 cm3 = 1 000 000 ml
• Measuring volumes of liquids – The volume must be taken at the meniscus level of the liquid. – Use a piece of white paper to enable the meniscus to be seen clearly. – The eye is positioned at the same level of the meniscus to avoid parallax error.
• Measuring volumes of solids – The volume of regular-shaped and irregular-shaped can be measured using water displacement method. – The object to be measured must be submerged in the measuring cylinder filled with water. – The volume of the water displaced is the volume of the object.
– The volume of a solid can also be measured using a displacement can or a Eureka can.– The volume of the water that flows out from the can is the volume of the solid measured.
– The volume of a light object can be measured with the aid of a weight, for example, a stone.– The stone which is tied to the cork enables the cork to be submerged in the water.
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