Syllabus Structure

Differentation between Ordinary & Higher Levels

Syllabus topics – 3 main headings – Biol, Physic, Chem, each is divided into 3 sections.

Ch 36 Measurement

Measurement

Syllabus Physics Section 3A: Force & Energy 3A1 Measurement in Science Topic & Sub - topic

Specific Learning outcomes On completion of this section, students should be able to Specific Learning outcomes

Using the Syllabus in Planning Lessons

A simple definition of physics is “the science of measurement”

The-scale-of-the-universe

Measuring For a measurement to be useful it must: be accurate have a unit.

Basic measurements in physics Length - Including areas and volumes Mass Time Temperature

LENGTH

Length Measuring instruments: List at least 3 items you could use to measure the length of an object. 1. 2. 3.

Length Measuring instruments: Tape measure Ruler Metre stick Opisometer (for small curves) Trundle wheel (for longer distances) Vernier callipers (for circular objects)

Length - Units List at least 3 units you could use to when measuring the length of an object. 1. 2. 3.

Length - Units millimetres (mm) centimetres (cm) metres (m) kilometres (km)

Video on Metre & Time / Measurement

Activity - Using a Ruler/Metre Stick Measure a number of objects at hand (length of desk, area of book cover, and so on). Compare your results. Are they the same? If not, can you say who has the more accurate result? How accurate can your measurements be?

Results Object Length Side of Copy 2. Side of book 3. Side of table 4. foot 5. The height of a person 6. The height of a chair 7. Side of a block

Curved length An Opisometer is used to measure the length of a small curvy line e.g. It is often used to measure the length of roads or rivers on a map.

Place the wheel of the Opisometer at the left side. Move the wheel along the curve, until you reach the end. Place the wheel on the zero mark of a ruler. Roll the metre stick along the metre stick until it stops. The position on the metre stick where the wheel stops corresponds to the length of the curve.

How to use an opisometer

Trundle wheel A trundle wheel is a larger version of the opisometer It is used to measure the length of longer distances - like the length of a road.

Vernier Callipers A vernier callipers is used to measure the diameter of circular objects – like the diameter of a marble

Vernier Callipers

Callipers Task: Use a callipers or a vernier calipers to measure the outside and inside diameter of a beaker in mm

Using a Vernier Calipers Object Length Tap 2. A coin 3. Pritt stick 4. A key chain 5. A pencil case 6. Tippex

Area

Area What formula do you use to measure the area of an object? Does it matter if it is a rectangle, a triangle, etc.? What Units do you use when measuring the area of an object?

Area How to measure area: If the object has straight sides use area formulas for rectangles and triangles. If the object has curved sides use the method of counting boxes on graph paper. Units square metres (m2) or square centimetres (cm2)

Measuring the area of a rectangle Multiply the length (l) by the width (w). Example: Area = l x w Area = 8 cm x 5cm = 40 cm2 8cm Width (w) Length (l) 5cm

Measuring the area of the block Area = length x width Area = ___cm x ___cm = ___cm2 ? cm Width (w) Length (l)

Measuring the area of curved shapes To measure the area of a shape that does not have straight edges, trace the shape on to graph paper with squares of a known size (e.g. 1 cm2) and count the number of squares covered by the shape.

Volume

OP2 measure mass and volume of a variety of solids and liquids

Q. What does the word Volume mean? 1. The Volume of an object is the amount of space it takes up.

Volume What formula do you use to measure the Volume of an object? Would you use the same formula if the object is a regular shaped object e.g. a matchbox or an irregular object e.g. stone? What Units do you use when measuring the Volume of an object?

Volume How to measure volume: If the object is a regular shaped box (like a matchbox) use the formula V = l x w x h. If the object is irregular use a graduated cylinder or an overflow can. Units cubic metres (m3) or cubic centimetres (cm3) or Litres (L)

NOTES 2. The formula for Volume is: Length x Width/Breadth x Height 3. Volume is measured in centimetres cubed (cm3), metres cubed (m3) or Litres (L)

Ex. Calculate the VOLUME of the REGULAR SOLID 2.0 cm 3.0 cm ANS: 24cm 3 4.0 cm

Measuring the volume of a regular shaped box Multiply the length (l) by the width (w) by the height (h) of the object. Example: V = l x w x h V = 8 cm x 2.5 cm x 3 cm = 60 cm3 h w l 3 cm 2.5 cm 8 cm

To Do Find the volume of 2 blocks.

Use a Graduated Cylinder. Q. How can we measure the volume of liquid? Use a Graduated Cylinder.

Practical Using a beaker, graduated cylinder & water, find the volume of liquid. Be careful you don’t break the graduated cylinder .

VOLUME OF A LIQUID Volume of liquid =50 cm3 50 cm3

Measuring the volume of an irregularly shaped object that sinks in water Graduated cylinder

METHOD Fill the Graduating Cylinder with water to 20 cm3 Put the object in. Record the level of water. Subtract the two readings.

Practical Using a graduated cylinder & water, find the volume of a stone. Be careful you don’t break the graduated cylinder .

Measuring the volume of an irregularly shaped object that floats in water Overflow can

Practical Using an overflow can, a graduated cylinder, stone & water, find the volume of the stone. Be careful you don’t break the graduated cylinder .

MASS

Mass Mass is the amount of matter (material) in an object. Measuring instruments: Mass balance. Units kilogram (kg) or gram (g) Weighing scales but remember weight [a force] is connected to but not the same as mass [not a force].

Q) Which has a greater mass :- A kilogram of feathers or a kilogram of iron? Answer Neither they both have the same mass - a kilogram

Q. How can we measure mass? A. Place the object on an electronic balance.

Q) Which has the greatest mass? Q. If you take the same volume of different substances, would they have the same mass, YES / NO? Iron Wood Water 1 cm3 1 cm3 1 cm3 0.50 g 1.00 g 8.00 g IRON Q) Which has the greatest mass?

NOTES 4. The Mass of an object is the amount of matter in it. 5. Mass is measured in grams (g) or Kilograms (Kgs).

Results Object Mass Copy 2. book 3. pen 4. Pencil case 5. rubber 6. journal 7. iPad

Problems to Solve

VOLUME & MASS OF A REGULAR SOLID 3.0 cm 6.0 cm m = 240 g 5.0 cm

METHOD Find the Volume. Measure the three lengths - V = L x W x H 3. Find the Mass of the solid on a balance.

RESULTS Volume = 3 x 6 x 5 = 90cm3 Mass = 240g

ACTIVITY Using 2 blocks of wood, write the following table in your copy and fill it in. Mass in g Length in cm Width Height Volume in cm3 1. 2.

VOLUME & MASS OF AN IRREGULAR SOLID M = 360 g 80 cm3 50 cm3

METHOD Find the Mass of the solid on a balance. Fill the Measuring Cylinder with Water to a known Volume. Add the Object. Work out the Volume of Water that is displaced. Write down all your results.

RESULTS Initial Volume of Water = Final Volume of Water = Volume of Object = Mass = 360g

ACTIVITY USING GRADUATED CYLINDER Using 2 irregular objects, write the following table in your copy and fill it in. Mass in g Initial Volume in cm3 Final Volume of Object 1. 2.

VOLUME and MASS OF AN IRREGULAR SOLID OR use an Overflow Can to find the Volume. STONE m = 440 g 40.0 cm3

Find the mass of the solid on a balance. Add water until just overflowing. Place a Graduated Cylinder under the spout. Add the Object. Collect the Water and read off the Volume.

ACTIVITY USING OVERFLOW CAN Using 2 irregular objects, write the following table in your copy and fill it in. Mass in g Volume of Water/ Object in cm3 1. 2.

Review Questions 1. What do we use to find the volume of an irregular solid? HINT 2.What do we use to find the mass of an object? HINT

Time Time allows change to happen. Measuring instruments: Units Stop watch. Electronic timer (for very short times). Units seconds (s), minutes (m) and hours (h or hrs) (multiply each time by 60 to use the smaller measure)

Temperature Temperature measures how hot or cold an object is. Measuring instrument: Thermometer. Unit: degrees Celsius (0C)