1.6 Discussion Activity Physical quantity SI Unit Symbol Length metre Mass Kilogram Kg Temperature Kelvin K Electrical current Ampere A Time second s

MASS The mass of an object is the quantity of matter contained in the object. The SI unit for mass is kilogram (kg).

WEIGHT The earth pulls objects to its centre. This pull is called the force of gravity or gravitational force. The weight of an object is the pull of the Earth on the object The SI unit for weight is Newton (N).

Which one is heavier?

WEIGHT AND MASS WEIGHT MASS Quantity of matter contained in an object. DIFFERENCES Quantity of matter contained in an object. The pull of the Earth’s gravity on that object. Kilogram (kg) Newton (N) Lever balance Triple beam balance Newton spring balance Compression balance Mass of an object does not change Weight of an object changes from place to place Not effect by gravity Effect by gravity DEFINITION SI UNIT MEASURING TOOLS CHARACTERISTIC PROPERTY Also measured in grams(g) and miligrams(mg) 1 kg=1 000 g 1 g=1 000 mg

WEIGHT AND MASS Relationship between weight and mass: 1 N = 100 g 10 N = 1 000 g = 1 kg Why weight of an object changes from place to place? The Earth’s gravitational pulls different in different places. - Weight of an object is heavier at the North Pole and South Pole than at the equator. The moon gravitational pull is only 1/6 of the Earth’s. - Example: An astronaut weighing 600 N on the Earth will weigh only 100 N on the moon.

MEASURING TOOLS Measurement of length Measurement of the diameter of an object Measurement of area Measurement of volume of liquid Measurement of volume of solids

Topic : Measurement of length What is length? Length is the distance between two points. The SI unit for length is metre(m),but the units kilometre(km), centimetre(cm) and milimetre(mm) are also used. How length can be measured? 1 cm = 10mm 1 m = 100 cm 1 km = 1000 m Length Measuring tools 1) Straight line Metre ruler Measuring tape 2) Curved line Thread and ruler Opisometer NOTE: To get accurate or precise reading, three(3) measurements are usually taken

Measurement of diameter Topic : Measurement of diameter What is diameter? A straight line drawn from side to side through the centre of circle. How diameter can be measured? diameter 2 types Internal diameter External diameter Diameter Measuring tools Internal diameter Internal calipers and ruler External diameter External calipers and ruler

Topic : Measurement of Area √ X What is area? Area is the total surface or space occupied by an object The units for area are square metres (m²) square centimetres (cm²) square milimetres (mm²) Types of area Area of regular shapes Area of irregular shapes Area of How to calculate 1)Square/ rectangle Area = length x width 2) Triagle Area =(½ )x base x height Estimated by using graph paper Examples: leaves & petals √ X

Topic : Measurement of Area √ X What is area? Area is the total surface or space occupied by an object The units for area are square metres (m²) square centimetres (cm²) square milimetres (mm²) Types of area Area of regular shapes Area of irregular shapes Area of How to calculate 1)Square/ rectangle Area = length x width 2) Triangle Area =(½ )x base x height Estimated by using graph paper Examples: leaves & petals √ X

Topic : Measurement of Volume What is volume? Volume is the total space occupied by an object The units for volume are cubic metres (m³) cubic centimetres (cm³) cubic milimetres (mm³) liters (∫) and mililitres(m∫) 1 m∫ = 1 cm³ 1 ∫ = 1 000 m∫ = 1 000 cm³ Types of volume Volume of liquids Volume of solids 2 types of solids Regular-shaped Irregular-shaped Measured by: Measuring cylinder Pipette Burette Determined by using water displacement method

Topic : Measurement of Volume What is volume? Volume is the total space occupied by an object The units for volume are cubic metres (m³) cubic centimetres (cm³) cubic milimetres (mm³) liters (∫) and mililitres(m∫) 1 m∫ = 1 cm³ 1 ∫ = 1 000 m∫ = 1 000 cm³ Types of volume Volume of liquids Volume of solids 2 types of solids Regular-shaped Irregular-shaped Measured by: Measuring cylinder Pipette Burette Determined by using water displacement method

End of chapter 1 yahoooo.....