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(1-2) Standards of measurement. Standard:. Look at this roll of string: 150 what? 150 ft? 150 cm? 150 m? Measurement = Number + Unit Standard unit: what all people agree on and understand. 150. System of Measurement. Meter System Most of the world. m, kg, cm, N…
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Standard: • Look at this roll of string: • 150 what? 150 ft? 150 cm? 150 m? • Measurement = Number + Unit • Standard unit: what all people agree on and understand. 150
System of Measurement • Meter System • Most of the world. • m, kg, cm, N… • The basis for the SI (International system of units) English System • USA • ft, mile, pound… Both systems are equally accurate.
Measuring Distance (Length): • Length is the distance between two points. • SI base unit for length is m • We need to use different unites sometimes: • cm for things like a pencil • Km for long distances like between RAK and Dubai. • Remember: • 1m = 100 cm • 1Km = 1000 m • 1cm = 10 mm • 1dm = 10 cm
Measuring Volume • Volume: the amount of space occupied by an object. • You’ll learn how to measure the volume of: • Regular solids, like a cube. • Liquids. • Irregular solids, like a pencil or a crown. Ms. Rania Abdelbaqi - IAT/RAK
Volume of regular solids: Ex: a cube V = l x w x h = 5 cm x 5 cm x 5 cm = 125 cm3 Where cm3 is a volume unit.
Volume of liquids: -By graduated cylinders. -Most common units are 1 mL = 1 cm3 1 L = 1 dm3 - Ex: how many cubic centimeters are in 1.5L? (check your note book for the answer)
3. Volume of irregular solids: These are the things that don’t have regular sides to measure. Their volume can be measured by water displacement method. (→ next slide)
1.Read the volume of water before immersing the crown in water. 3. The difference in the water volume, is the volume of the crown. (300 mL) 2300 mL 2000 mL 2. Read the volume of water after immersing the crown in water.
Measuring Mass • Mass: How much matter in an object. • Units: kg, g, mg, …. • Remember: 1 kg = 1000 g 1g = 1000 mg • Example: how many kilograms are in 6430 mg? (check your copy book for the answer)
Density: is the mass per unit volume. Density = • What is the density of an object having a mass of 10g and a volume of 2 cm3 ? Density = = 5 g/cm3 The unit of density is g/cm3