education in quantum physics and education physics project topics and also education scotland higher physics questions
Dr.ShaneMatts,United States,Teacher
Published Date:23-07-2017
Your Website URL(Optional)
Comment
ORDINARY LEVEL SECONDARY
EDUCATION PHYSICS
PRACTICALS
USING LOCALLY
AVAILABLE MATERIALS
TEACHER'S GUIDEPreface
As the era of Alternative to Practical comes to an end, it is my hope that
science teachers nationally embrace the new paradigm, that science lessons
should be student-centred, competence-based, activity-oriented, and connect
with student's life experience. Every student in Tanzania should perform
practical exercises, not just the few tested on national exams, but the wider
range of hands-on activities teachers should employ to build a deep under-
standing in their students.
Educational research has identi ed two obstacles to the universal imple-
mentation of hands-on science education. First, many teachers themselves
learned in Alternative to Practical schools and therefore lack essential expe-
rience with hands-on science. Every e ort is already under way to overcome
this de ciency. A national in-service training program reaches thousands of
educators annually, and a Teachers' Guide has already been written to guide
teachers on standard execution of dozens of hands-on activities in Physics.
The remaining challenge is a fallacy rooted in ignorance and compla-
cency: the idea that the materials required for hands-on science teaching are
unavailable to most schools. We reject the notion that science education re-
quires expensive, imported materials. Everything required to teach modern
science is already available in our villages and towns. The challenge is simply
to begin.
Science belongs to Tanzania as much as any country in the world. The
law of gravity respects no national boundaries; we all feel its e ect and can
measure its strength. Those who decry the use of locally available materials
as \stone age science" misunderstand the meaning of Science - that it applies
universally, in any situation, with any material. Dependence on expensive
imported materials teaches students that Science is a foreign concept, to be
memorized rather than understood, and that Science lacks application to
daily life. Science is the birthright of humanity, as much as Language or
Mathematics or Music, and the time has come to embrace what we already
own.
This Companion Guide was written to equip teachers with the knowledge
1and skills to deliver hands-on science lessons in any school, especially those
without standard science laboratories. I hope that this Companion Guide will
also inspire school inspectors, examiners, curriculum developers and college
tutors to increase their emphasis on the importance of hands-on education,
and to reject material de ciencies as an excuse for any absence of practical
work. In the same spirit, this Companion Guide seeks to expand the range of
approaches to learning Physics and it is my hope that the many stakeholders
in science education will embrace alternative methods that enable quality
delivery of science education for every student.
Prof. Hamisi O. Dihenga
Permanent Secretary
Ministry of Education and Vocational Training
April 2011
2Background
Motivation for Writing this Companion Guide
Quality science education requires students to perform experiments with their
own hands. Unfortunately, research on the situation of secondary science
education shows that many students do not perform such experiments. This
is due to several factors, all of which can be addressed.
First, many teachers themselves do not have enough experience with sci-
ence experiments, largely due to the absence of practical education when they
themselves were students. Teacher training programs and the new Physics
Teachers' Guide seek to address this shortcoming.
Second, this lack of experience leads to low con dence for trying new
experiments. Science can only be learned through experimentation just
as students must perform activities to truly understand the material on the
syllabus, so too must teachers. The teacher using this book is strongly en-
couraged to perform every one of these experiments to deepen his or her
fundamental understanding of Physics.
Third, most schools lack traditional laboratory facilities. Many educators
therefore assume that this means hands-on activities are impossible.
To address this misconception, the Ministry of Education and Vocational
Training has decided to prepare this Physics Companion Guide. The ob-
jective is to ensure that all secondary school Physics teachers can conduct
practical work even if they do not have access to a standard Physics lab-
oratory. Speci cally, this book demonstrates that many quality hands-on
science experiments are possible with very basic materials. The experiments
in these pages require materials available in villages or, at worst, in a regional
capital. Standard laboratory materials certainly add value to science teach-
ing; this book merely makes it clear that they are not required as a condition
for provision of quality education.
3Procedures Followed in Developing the Companion Guide
This Companion Guide builds on the work of the Physics Teachers' Guide. In
preparation for the Teachers' Guide, educators and subject experts identi ed
activities for most of the topics on the ordinary level syllabus. To prepare this
Companion Guide with Local Materials, a team of secondary school teachers
and science experts from TIE devised methods for performing the activities
of the Physics Teachers' Guide using low cost and locally available materials.
Description of the Companion Guide
Practical investigations address speci c syllabus content. Each topic begins
with a short summary of relevant syllabus material. Each activity is intro-
duced in that context as a method for students to experiment with the topic
of the day. Each activity then states clearly its objectives. Generally, these
objectives match the objectives in the Physics Teachers' Guide. The teacher
should use both resources, side by side, when preparing activities.
Each activity description then lists the required materials. Instructions
for the local manfacture of several items are given in the rst section of
this book in the section called \Manufacture of Apparatus." If an activity
requires the use of materials from this section they will be marked with a
star () in the materials list. For example, the materials list may look like
this: \Materials: beakers, test tubes, plastic spoon" If you see this, you
can refer to the materials list to see a suggested method for making your own
beakers.
After listing the objectives and materials, the description lists any hazards
associated with the activity and precautions teachers should take to minimize
these hazards. Next are procedures, both for preparing the activity and
for executing the experiment. While preparation steps are generally to be
performed by the teacher, the activity steps are often to be performed by the
students themselves.
The description next outlines the expected results and what conclusions
may be drawn from them. Then follow the instructions for cleaning up.
The section closes with questions useful for guiding classroom discussion.
Students should discuss these questions in groups and share their answers
with the class.
Many of the activities also include a \Notes" section to provide the teacher
with additional information about the activity. This information may be
practical or theoretical.
4Application of the Companion Guide
This guide is written for teachers to acquire the knowledge and skills needed
to lead students in hands-on science learning. While all of the experiments
in this companion guide may be performed as demonstrations, the intention
is for many of the activities to be performed by the students themselves,
individually or in small groups, under the direction of the teacher.
To prepare for such lessons, the teacher should attempt these experiments
rst. Especially for teachers who are new to hands-on science experimenta-
tion, these experiments should, in themselves, provide a useful training. If
there are multiple subject teachers at the school, they are encouraged to ex-
periment together. Once the teacher has achieved comfort and pro ciency
with the given activity, the teacher should integrate the activity into relevant
lesson plans.
The vision is not for students to be spectators of science, but players
themselves.
Finally, the teacher is advised to not regard the activities in this book
as the only possible activities nor even the only possible activities for these
particular objectives. Every educator has ideas for e ective teaching and new
ideas are the substance of development. After trying an activity, the teacher
is strongly encouraged to devise and attempt alternatives. When possible,
teachers should collaborate with each other on such experiments, and share
with each other the ideas they develop.
The vision is not for teachers to be passive implementors, but innovators
themselves.
5Contents
1 Laboratory Equipment 10
Checking Voltmeters and Ammeters/Galvanometers . . . . . . . . . 12
Voltmeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Ammeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Usable Ammeters . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
2 Physics Activities for Form I 15
Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
Construction of a Metre Rule . . . . . . . . . . . . . . . . . . 15
Construction of a Measuring Cylinder . . . . . . . . . . . . . . 16
Construction of Beam Balance . . . . . . . . . . . . . . . . . . 17
Measurement Errors . . . . . . . . . . . . . . . . . . . . . . . 19
Density and Relative Density . . . . . . . . . . . . . . . . . . . . . 20
Relative Density of a Liquid . . . . . . . . . . . . . . . . . . . 20
Construction and Use of a Hydrometer . . . . . . . . . . . . . 22
Applications of Material Densities . . . . . . . . . . . . . . . . 25
Archimedes' Principle . . . . . . . . . . . . . . . . . . . . . . . . . 27
Construction of Eureka Can . . . . . . . . . . . . . . . . . . . 27
Flotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Conditions of Flotation . . . . . . . . . . . . . . . . . . . . . . 28
Properties of Matter . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Surface Tension in Bubbles . . . . . . . . . . . . . . . . . . . . 29
Changing Surface Tension . . . . . . . . . . . . . . . . . . . . 31
Cohesion in a Moving Liquid . . . . . . . . . . . . . . . . . . . 34
Elasticity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Determining Adhesion and Cohesion . . . . . . . . . . . . . . 36
Capillarity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Conservation of Energy . . . . . . . . . . . . . . . . . . . . . . . . . 40
Potential Energy of a Spring . . . . . . . . . . . . . . . . . . . 40
Forces . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
Presence of Gravity . . . . . . . . . . . . . . . . . . . . . . . . 42
6Making a Spring and a Spring Balance . . . . . . . . . . . . . 43
Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
Automatic Flushing Tank . . . . . . . . . . . . . . . . . . . . 46
Cartesian Diver . . . . . . . . . . . . . . . . . . . . . . . . . . 47
A Siphon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Liquid Pressure and Depth . . . . . . . . . . . . . . . . . . . . 50
Making a Magdeburg Hemisphere . . . . . . . . . . . . . . . . 52
Air Pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
The E ect of Surface Area on Pressure . . . . . . . . . . . . . 55
Light . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
Light in a Straight Line . . . . . . . . . . . . . . . . . . . . . 57
Pin Hole Camera . . . . . . . . . . . . . . . . . . . . . . . . . 58
Laws of Re
ection . . . . . . . . . . . . . . . . . . . . . . . . 60
3 Physics Activities for Form II 62
Static Electricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
Concept of Static Electricity . . . . . . . . . . . . . . . . . . . 62
Construction of an Electroscope . . . . . . . . . . . . . . . . . 63
Detection of Charges . . . . . . . . . . . . . . . . . . . . . . . 66
Current Electricity . . . . . . . . . . . . . . . . . . . . . . . . . . . 67
Conductors and Insulators . . . . . . . . . . . . . . . . . . . . 67
Finding Electric Circuit Components . . . . . . . . . . . . . . 68
Measuring Emf of a Cell . . . . . . . . . . . . . . . . . . . . . 70
Magnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Magnetic and Non-magnetic Materials . . . . . . . . . . . . . 72
Magnetic Fields . . . . . . . . . . . . . . . . . . . . . . . . . . 73
Earth's Magnetic Field . . . . . . . . . . . . . . . . . . . . . . . . . 75
Creating a Simple Compass . . . . . . . . . . . . . . . . . . . 75
Magnetic Dip Gauge . . . . . . . . . . . . . . . . . . . . . . . 77
Newton's Laws and Forces . . . . . . . . . . . . . . . . . . . . . . . 79
Inertia and Newton's First Law of Motion . . . . . . . . . . . 79
Conservation of Linear Momentum . . . . . . . . . . . . . . . 80
Bottle Rocket . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
Matchstick Rocket . . . . . . . . . . . . . . . . . . . . . . . . 84
Veri cation of Newton's First Law of Motion . . . . . . . . . . 87
Rotation and Equilibrium . . . . . . . . . . . . . . . . . . . . . . . 88
Centre of Gravity . . . . . . . . . . . . . . . . . . . . . . . . . 88
Veri cation of the Principle of Moments . . . . . . . . . . . . 90
Simple Machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
Pulley . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91
74 Physics Activities for Form III 95
Friction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Concept of Friction . . . . . . . . . . . . . . . . . . . . . . . . 95
Limiting Friction and the Coecient of Static Friction . . . . 96
Re
ection of light . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
Total Internal Re
ection in Water . . . . . . . . . . . . . . . . 99
Refraction and Colour . . . . . . . . . . . . . . . . . . . . . . . . . 100
Dispersion of White Light: Part 1 . . . . . . . . . . . . . . . . 100
Newton Colour Wheel . . . . . . . . . . . . . . . . . . . . . . 102
Measuring Refractive Index of Glass . . . . . . . . . . . . . . . 104
Refraction of Light in Glass . . . . . . . . . . . . . . . . . . . 108
Heat Transfer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
Designing a Calorimeter . . . . . . . . . . . . . . . . . . . . . 110
Heat Conduction . . . . . . . . . . . . . . . . . . . . . . . . . 111
Convection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 114
Radiation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
Thermal Expansion . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Bimetallic Strip . . . . . . . . . . . . . . . . . . . . . . . . . . 119
Thermal Expansion of Gases . . . . . . . . . . . . . . . . . . . 121
Thermal Expansion of Solids - Breaking Glass . . . . . . . . . 123
Thermal Expansion of Liquids . . . . . . . . . . . . . . . . . . 124
Thermal Switch . . . . . . . . . . . . . . . . . . . . . . . . . . 127
Change of State . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
Boiling at Room Temperature . . . . . . . . . . . . . . . . . . 129
Heat Capacity and Latent Heat . . . . . . . . . . . . . . . . . . . . 131
Latent Heat of Fusion . . . . . . . . . . . . . . . . . . . . . . 131
Vapour . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
Measuring Humidity with a Hygrometer . . . . . . . . . . . . 133
Gas Laws . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Boyle's Law . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
Charles's Law . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
5 Physics Activities for Form IV 140
Electricity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
Creating a Leclanche Cell. . . . . . . . . . . . . . . . . . . . . 140
Construction of a Metre bridge and Potentiometer . . . . . . . 142
Creating a Light Bulb . . . . . . . . . . . . . . . . . . . . . . 146
Fuse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148
Making an Electric Heater . . . . . . . . . . . . . . . . . . . . 149
Inverter: Converting DC to AC . . . . . . . . . . . . . . . . . 151
Semiconductors and Semiconductor Devices . . . . . . . . . . . . . 157
8Forward and Reverse Biased Diodes . . . . . . . . . . . . . . . 157
Full-Wave Recti er . . . . . . . . . . . . . . . . . . . . . . . . 159
Half-Wave Recti er . . . . . . . . . . . . . . . . . . . . . . . . 162
Waves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
Construction and Use of Slinky Spring . . . . . . . . . . . . . 165
Construction of a Ripple Tank . . . . . . . . . . . . . . . . . . 167
Behaviour of Waves . . . . . . . . . . . . . . . . . . . . . . . . 169
Sound . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
Construction and Use of a Simple Sonometer . . . . . . . . . . 171
Wave Propagation in Solids . . . . . . . . . . . . . . . . . . . 173
Sound Ampli er . . . . . . . . . . . . . . . . . . . . . . . . . . 174
Determination of Resonance Frequency . . . . . . . . . . . . . 176
Speed of Sound in Air . . . . . . . . . . . . . . . . . . . . . . 178
Electromagnetism . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Simple Motor . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
Construction of Galvanometer . . . . . . . . . . . . . . . . . . 183
Force on a Current-Carrying Wire in a Magnetic Field . . . . 185
Water Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
Wind Energy . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Astronomy . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 194
Solar System Mobile . . . . . . . . . . . . . . . . . . . . . . . 194
Star Gazing . . . . . . . . . . . . . . . . . . . . . . . . . . . . 195
9Chapter 1
Laboratory Equipment
Throughout this book you will see materials that have been marked with
an asterisk (). These are locally available materials which can be made or
purchased for your laboratory. The guide for using and making these local
materials are found in the following section.
Beakers
Use: To hold liquids
Materials: Water bottles, juice containers, lids for bottles or jars, and a knife
Procedure: Take empty plastic battles of di erent sizes. Cut them in half.
The base can be used as a beaker.
Delivery Tube
Use: For the movement and collection of gases, capillary tubes, hydraulic
press
Materials: Straws, pen tubes, or pawpaw petioles
Needles
Use: Compass needles, optical pins, making holes,
ying wire
Materials: Oce pins, sewing needles, needles from syringes
Droppers
Use: To add small amounts of liquid to something
Materials: 2 mL syringes
Procedure: Take a syringe. Remove the needle.
10Funnel
Use: To guide liquid or powder into a small opening
Materials: Empty water bottles
Procedure: Take an empty water bottle and remove the cap. Cut them in
half. The upper part of the bottle can be used as a funnel.
Heat Source
Use: Heating substances
Materials: Candles, kerosene stoves, charcoal burners, or a moto poa stove
Procedure: Cut a metal can in half and add a small amount of moto poa
Stopper
Use: To cover the mouth of a bottle, hold a capillary tube
Materials: Rubber, cork, plastic water bottle cap
Procedure: Cut a circular piece of rubber. If the stopper is being used to
hold a capillary tube, a hole can be melted in a plastic cap or rubber stopper.
Water Bath
Use: To heat substances without using a direct
ame
Materials: Heat source, water, and a cooking pot
Procedure: Bring water to a boil in a small aluminium pot, then place the
test tubes in the water to heat the substance inside the test tube.
Circuit Components
Use: Building simple circuits, Ohm's Law, ampli er, wave recti ers
Materials: Broken radio, computer, stereo, other electrical devices
Procedure: Remove resistors, capacitors, transistors, diodes, motors, wires,
transformers, inductors, rheostats, pulleys, gears, battery holders, switches,
speakers and other components from the devices.
Masses
Use: Calibrating and using beam balance and spring balance, Hooke's Law
Materials: Known masses, beam balance, sand, stones, plastic bags, thread,
paper, tape, pen
Procedure: Use a beam balance and known masses at a duka or nearby school
to measure exact masses of sand or stones. Use a marker pen to mark the
11masses on the stones. If using sand, place a small piece of plastic bag on
the scale pan and ll it with sand until you have the required mass. Tie the
sand in the plastic bag with thread. Use paper and tape to make a label
on the outside, marking the mass with pen. These masses can be used in
your school. Water can also be as a known mass. The density of water is 1.0
g/mL, so you can use a known volume of water in a bottle to create a known
mass. Be sure to also account for the mass of the bottle.
Plane Mirror
Use: Laws of Re
ection, periscope, water prism
Materials: piece of thin glass, kibatari, Optional: small pieces of mirror glass
are cheap or free at a glass cutter's shop
Procedure: Light the kibatari so that it creates a lot of smoke. Pass one side
of the glass repeatedly over the kibatari until that side is totally black. The
other side acts as a mirror.
Iron Filings
Use: To map magnetic elds
Materials: Steel wool / Iron wool used for cleaning pots
Procedure: Rub some steel wool between your thumb and ngers. The small
pieces that fall are iron lings. Collect them in a matchbox or other container
to use again.
Checking Voltmeters and Ammeters/Galvanometers
Needed: Meters to check, a couple of wires, some resistors and a fresh battery.
Important note: There is a wrong way to hook up the meter. The needle
will try to detect down because negative and positive are swapped. If the
reading is zero, make sure that you try the opposite connection to be sure.
Voltmeters
Hook up the voltmeter across the battery. The battery is probably 1.5 V,
but do not worry if you see 1.1, 1.2, even if using a brand new battery. Try
not to use a battery that reads much below 1 V on several di erent meters.
12Unusable Voltmeters
Totally dead, no detection of the needle
Voltage reading jumps excessively. Ensure that the connections are
solid and test again.
Measured voltage is totally wrong, not close to 1.5 V
Usable Voltmeters
Read a voltage close to 1.5
If the voltage if not 1.5 exactly, the voltmeter is probably working and
the battery is just old a bit.
Ammeters
Hook up the ammeter in series with a resistor. Because you do not necessarily
know the condition of the ammeter before testing, be sure to have several
di erent resistors on hand. An ammeter may appear not to work if resistance
is too high or too low. Start testing di erent ammeters.
Unusable Ammeters
Totally dead, no detection of the needle
Current reading jumps excessively (but check connections)
Totally wrong, reads much di erent from other ammeters
Usable Ammeters
Reads a current similar to other ammeters.
Hard to say exactly what current, but feel free to calculate based on your
resistor using V=IR, although do not forget that there is some internal re-
sistance r of battery, so V = I(R + r).
The resistance of the resistor is usually coded on the resistor in a series in
stripes - see the instructions under Resistors in the Sources of Equipment
section.
Tip: You can hold the wires onto the battery with your ngers; the current
is far too low to cause a shock.
Other: Now that you have tested to see if your voltmeters and ammeters
13work, you can feel free to check all of them for accuracy, by calculating ex-
pected values and comparing between meters. Most practicals will still work
alright with somewhat accurate meters.
14Chapter 2
Physics Activities for Form I
Measurement
Construction of a Metre Rule
Learning Objective
To construct and use a metre rule.
Background Information
Length is an interval between two points. It is usually measured in metric
units like the metre (m), millimetre (mm), centimetre (cm), kilometre (km).
Materials
Wooden board, pen/pencil, a handsaw, ruler or tape measure
Preparation Procedure
1. Use the saw to cut a piece of wood 100 cm x 3.5 cm x 0.5 cm.
2. Use a ruler to mark a scale in cm on the wood.
Activity Procedure
Use the new metre ruler to measure length of di erent objects.
Discussion Question
What other objects can be arranged in order to measure distance?
15Notes
Instead of a wooden block, string can be used by making knots at a de nite
intervals.
Construction of a Measuring Cylinder
Learning Objective
To construct and use a measuring cylinder.
Background Information
A measuring cylinders measures the volume of liquids in millilitres (mL).
Materials
Plastic bottles of di erent sizes, syringes (30-50 mL), marker pen, ruler,
bucket full of water
Preparation Procedure
1. Using the syringe, take a known volume of water from the bucket.
2. Transfer the known volume of water in the syringe to the empty plastic
bottle.
3. Using the marker pen, mark the level of water in the plastic bottle with
the volume from the syringe.
4. Repeat this step for a range of volumes, marking each volume on the
side of the bottle.
5. Use a ruler to complete the scale.
Activity Procedure
Use the constructed measuring cylinder to measure volumes of di erent liq-
uids.
Clean Up Procedure
Remove waste and return materials to their proper places.
16Discussion Question
Explain how to use a measuring cylinder.
Notes
A measuring cylinder cannot be used to measure the volume of a solid by it-
self, though if the solid is immersed in a liquid, the volume can be determined
with a measuring cylinder. The volume of granular and porous materials can
also be measured if they are immersed in a liquid in a measuring cylinder.
Construction of Beam Balance
Learning Objective
To construct and use a beam balance.
Background Information
Mass is a fundamental quantity and is measured by using a beam balance.
In physics mass is usually measured in grams (g) or kilograms (kg).
Materials
Wooden bar 30 cm x 2 cm, string/wire, ruler, pencil/pen, 2 large plastic
bottles, nails, heat source
Preparation Procedure
1. Cut a piece of wood block to 30 cm x 2 cm.
2. Find the balancing point and then mark the point using a pencil or
pen.
3. Make a hole at the balance point using a hot nail.
4. Mark 5 cm spaces on each side of the hole using a ruler.
5. Cut 2 plastic bottles about 3 - 4 cm from the bottom.
6. Make 3 round holes in the bottom of a plastic bottle at equal intervals.
These will be used as scale pans.
7. Tie pieces of thread/wire about 15 cm length into the holes of the
bottom of a plastic bottle.
17String
Plane Wood
String
Strings
Plastic Bottle Base
Figure 2.1: A beam balance
8. Join the upper ends of the thread/wires together.
9. Suspend the wooden block by using a piece of string/wire tied through
the centre hole.
Activity Procedure
Use the beam balance to measure the masses of di erent objects in the class-
room.
Clean Up Procedure
Return all materials to their proper places.
Discussion Question
How can you improve the beam balance?
18Notes
There are di erent kinds of balances, such as a digital balance, double beam
balance, single beam balance and triple beam balance. Each can be used to
measure mass according to its sensitivity.
Measurement Errors
Learning Objectives
To understand the meaning of experimental error
To understand the importance of accurate measurement and sample
size
Background Information
Measurement is one of the most important aspects of science. However, it
is impossible to make a perfect measurement because of our own errors and
errors in the tools that we use. To improve our accuracy, we take many
measurements and compare them to get an average result. However, it is
important to understand the source of errors, how to account for them and
how to reduce them. Di erent people measure di erently, and even one
person will measure di erently from one moment to another.
Materials
Metre rules, stopwatches, other measuring instruments, materials to measure
Preparation Procedure
Collect di erent tools used for measuring, like metre rules or rulers, stop-
watches, syringes, etc.
Activity Procedure
1. Draw a line on the board or
oor.
2. Have several students measure the line and secretly record their results.
3. Collect the results from the students and record them on the board.
Observe any di erences.
4. Distribute stopwatches to several students.
19
Advise:Why You Wasting Money in Costly SEO Tools, Use World's Best Free SEO Tool Ubersuggest.
