G9 Physics - The Building Blocks of Measurement Aug2013

Grade

9 Physics

Title

The Building Blocks of Measurement

Student

Teacher

MYP9: The Building Blocks of Measurement AB Assessment – Electricity for All

You will have one assessment of criteria A and B. This assessment is entitled Electricity for All

Scenario Electricity is a very useful form of energy. This is because it can be transferred (or transformed) into many other forms of energy. For example, electrical energy can be transferred into light energy in a light bulb.

The difficulty is in getting enough electricity everywhere – in cities, towns, villages and remote communities.

A small town is planned on Joule Island – shown on the next page. Electricity needs to be supplied to all homes, offices and factories to meet their needs. The island has various natural resources available, including; •

A forest.

•

A natural lake in the mountains on the island.

•

Hot springs.

In addition, the mainland is 50km away – a relatively short trip by boat.

Your task is to; •

Decide on a suitable method of generating and transmitting electricity so that all homes, offices and factories planned for the island have sufficient electricity.

•

Consider the advantages and disadvantages of your method compared to other methods.

•

Evaluate the effectiveness of your method in terms of the efficiency of the energy transfers involved.

•

Consider the implications of your method in terms of the moral, ethical, economic, political, social and environmental impact.

•

Include a full bibliography with references in the MLA style.

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MYP9: The Building Blocks of Measurement AB Assessment – Electricity for All

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MYP9: The Building Blocks of Measurement C Assessment

For the end of topic assessment you will need to revise as follows;

Topic

Pages

Fundamental and derived units; Unit conversions; Standard form; Uncertainty, precision and accuracy.

Representing uncertainties on a graph.

Pendulum Experiment

How to look for pattern and trends in data; Lines of best fit (linear and curved).

How to find the gradient and intercept of a linear line of best fit; Circuit symbols; Trends in series and parallel circuits; Current, potential difference and resistance in circuits; Adding resistances in series, parallel and combination circuits;

Resistance Experiment

Factors affecting the resistance of a wire.

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MYP9: The Building Blocks of Measurement DE Assessment – Resistance is Futile!

The title of this DEF assessment is called Resistance is Futile!

Scenario In order to distribute electricity over long distances, metal cables are used. These electricity cables over often very long – they can stretch over many kilometres.

It is crucial to make the distribution of electricity as efficient as possible. This means that it is important to avoid wasting energy as heat in the electricity cables.

In order to achieve this, one of the most important factors to consider is the resistance of the metal cable.

Your task will be investigate one factor that affects the resistance of a wire. The type of wire will be specified by your teacher.

You will need to; •

Consider the possible factors that affect the resistance of a wire.

•

If possible, conduct trial runs (preliminary work) to briefly look at the effect of each factor.

•

Decide on a factor to investigate in detail.

•

Design an experiment to investigate this factor.

•

Collect sufficient relevant data.

•

Process your data.

•

Present your data in the form of charts and graphs.

•

Analyse your data and reach a conclusion.

•

Evaluate the strengths and weaknesses of your data and describe improvements and further work.

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MYP9: The Building Blocks of Measurement Traffic Lights

â˜ş

No.

Question / Statement

1

I know the fundamental units of measurement.

2

I can give examples of derived units of measurement.

3

I can convert quantities from one unit to another

4

I know what is meant by independent, dependent and controlled variables.

5

I can design an experiment to investigate the effect of one factor.

6

I can calculate the average, range and uncertainty of a quantity.

7

I can draw an appropriate line of best fit and use it to make a conclusion.

8

I know what precision and accuracy are and can calculate their values.

9

I can describe what happens to the current in series and parallel circuits as more components are added.

10

I can describe what happens to the potential difference in series and parallel circuits as more components are added.

11

I can calculate current, potential difference and resistance in series and parallel circuits.

12

I know how electricity is transmitted to homes and buildings.

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MYP9: The Building Blocks of Measurement The Building Blocks of Measurement

Without warning, Mr O’Rourke caught time itself slipping away…

In this topic you will learn about; •

The S.I. system of measurement, fundamental and derived units;

•

Using standard form and converting between units;

•

Uncertainties, precision and accuracy;

•

Plotting data with uncertainties;

•

Drawing a line of best fit;

•

Measuring the gradient and intercept of the linear trend;

•

Basic series, parallel and combination circuits;

•

Current, potential difference, resistance and power in circuits;

•

Combinations of resistors;

•

Factors affecting the resistance of a wire.

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MYP9: The Building Blocks of Measurement Measuring What We Can See

A pendulum is a mass that hangs on the end of a thread or rod, like the one in the picture below.

They are found in lots of places, like grandfather clocks.

The large circular weight in the middle is moved to one side and then released to provide a regular swinging motion.

The question is – what factors will affect the period (the time for one full swing) of the pendulum?

Pendulums have been used in many measurements in Physics. The pendulum below – called Foucault’s Pendulum, named after the French physicist Léon Foucault.

This type of pendulum was designed in the 1850’s to show that the Earth rotated. This fact was already known but it was the first time that it could be demonstrated in such a simple way.

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MYP9: The Building Blocks of Measurement Pendulums

Wooden blocks

Equipment List Stand, boss, clamp Stopwatch

Thread / string Ruler Thread Small mass Small mass

Introduction In this experiment you will make some measurements using a simple pendulum, shown above.

You will learn how to; •

Decide on dependent, independent and controlled variables

•

Take some simple measurements

•

Calculate the average of a set of numbers

•

Calculate the uncertainty of a set of numbers

•

Represent data on a scatter-graph

•

Represent uncertainties on the same scatter graph.

•

Draw a line (curve) of best fit.

•

Compare your data to a theory (model).

•

Write a conclusion for your data, based on your graph.

•

Evaluate your data, based on your uncertainties and the comparison with the theory.

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MYP9: The Building Blocks of Measurement Pendulums

Here are the main factors that could affect the period of the pendulum.

•

The maximum horizontal displacement of the swing (measured from the centre - this is called the amplitude).

•

The mass

•

The length of the thread.

To begin with, build a pendulum of length 50cm, 20g mass.

•

Because the time for a single swing can be quite short, it is simpler to record the time for (say) 10 swings of a pendulum.

•

Record your preliminary results in the table below.

•

The uncertainty in the timing, using a regular stopwatch, is around 0.2 s.

Attempt

Amplitude

Mass

Length of thread

Time for 10 swings

cm

g

cm

±0.2 s

5

20

50

25

20

50

5

100

50

5

20

50

5

20

10

5

20

50

1

2

3

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MYP9: The Building Blocks of Measurement Pendulums!

Now write a short conclusion for each factor investigated.

Remember that if two values are within the uncertainty of your measurement then you should say that they are the same (i.e. you cannot say that they are definitely different) •

The effect of changing the amplitude.

•

The effect of changing the mass on the period

•

The effect of changing the length of the thread

Main Experiment - Variables Now you can decide on; •

The independent variable and its range of values (see below)

•

The dependent variable

•

Controlled variables and their values.

Number and Range of Measurements In an experiment it is good to take measurements over a wide range. Realistically, it is possible to build a pendulum with a length between 4cm and 200cm.

Around ten different lengths would be a good number of measurements. The period of a pendulum like this is typically around 1.0s, which means that if you measure only one swing then the uncertainty in the measurement will be significant. So it is better to time several swings of the pendulum – typically 10 or 20 – instead.

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First repeat

12

Second repeat

G9 Physics - The Building Blocks of Measurement Aug2013

Length/ cm

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Average Period /s

Pendulums

Third repeat

Time for ________ Swings of the pendulum, Âą 0.2 s

MYP9: The Building Blocks of Measurement

Range for the period /s

Processed Data Uncertainty in the period/ s

MYP9: The Building Blocks of Measurement Pendulums

You will need to; •

Plot your data – including the uncertainties as error bars.

•

Draw a suitable line (or curve) of best fit through the uncertainties.

•

Write a conclusion for your results.

•

Describe the trend of the line of best fit.

•

See if you can identify any pattern in the results (linear, non-linear, inverse proportion, quadratic…?)

•

What happens to the period when the length is doubled? Trebled? Quadrupled?

•

Choose values from your graph to support any conclusion that you make.

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MYP9: The Building Blocks of Measurement Measuring What We Cannot See

Electron beams are much more common than you might think – lighting is a discharge of electrons making striking images like the one above.

A similar effect can be seen in the famous Aurora Borealis and Aurora Australis.

Electron beams are also used in older type televisions – like the one drawn below.

Although the lighting is visible, we don’t actually see the electron beam. What we see is the light given off by air particles that have been excited by the fast moving electrons in the beam.

Similarly, in an old television, we don’t actually see the electrons making a picture. What we see are combinations of red, blue and green colours. These colours of light are emitted by chemicals called phosphors when the electron beam strikes them.

In this section we will look at how we can measure the effects of electrons as they pass through materials.

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MYP9: The Building Blocks of Measurement Circuits

In this part of the topic you will look at measuring what cannot be seen directly.

You will make measurement of electrical circuits – loops made of good conductors like copper along which electricity can flow.

To begin with, identify the circuit components below.

Components Resistor

Variable resistor

Ammeter

Battery

Voltmeter

Lamp

Open switch

Power Supply

Battery

Closed switch

Cell

A

V

+ 6V -

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MYP9: The Building Blocks of Measurement Electrical Current

An electrical current is made whenever there is a flow of charge – when charged particles move from A to B. The amount of charge is measured in Coulombs (C).

The amount of charge passing a point in each second is called the current;

Current is measured using an ammeter.

Example 1.

A charge of 50 C passes a point in a circuit in a time of 10 s. Calculate the current.

50

5 5 10

Example 2 A current of 1.5A flows through a component for 6.0 seconds. Calculate the charge that has gone through the component.

1.5 6.0 9.0

Question A current of 100 mA flows through a component, for a time of 20 ms. Calculate the charge that has passed through the component.

Show all working.

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MYP9: The Building Blocks of Measurement Current in Series 6V

A

P

A

R

A Q

Experiment 1 – where does the ammeter go?

Build the series circuit above – use 4 x 1.5V cells.

Place the ammeter in position P, measure the current and record the value in the table.

Repeat for position Q and R. Then write a conclusion for your results.

Experiment 2 – adding bulbs in series Build the circuit below with bulb P only.

Then add bulb Q to the circuit and measure the current.

Repeat this process for up to 5 bulbs. Then write a conclusion for your results.

6V

A

P

Q

G9 Physics - The Building Blocks of Measurement Aug2013

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R

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MYP9: The Building Blocks of Measurement Current in Parallel 3V

S

A P

A

R

A

First

Q

A

Second

Experiment 3- where does the ammeter go?

Build the parallel circuit above. Place the ammeter in position P, measure the current and record the value in the table.

Repeat for position Q, R and S. Then write a conclusion for your results.

Experiment 4- adding bulbs in parallel Build the circuit below with bulb P only. Record the current. Then add bulb Q to the circuit and measure the current.

Repeat this process for up to 5 bulbs and then write a conclusion for your results.

3V

A

P

Q

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MYP9: The Building Blocks of Measurement Checkpoint Current

Increases

One

Total

Amps

Seconds

Coulombs

Decreases

Ammeter

Many

Charge

Partial

Use the words in the box above to answer the following question.

An ammeter measures the ____________________ in a circuit, which is the rate of flow of charge.

Charge is measured in ____________________ and time in ____________________ .

So current, which is measured in _________________, is equivalent to units of _________________________ per _____________________.

In a series circuit, there is only ______________ loop or branch.

Therefore an ammeter will always measure the ______________________ current, which is the same at all points in the series circuit.

As more bulbs are added in series, the current _____________________.

In a parallel circuit, there are ______________ loops or branches.

An ammeter placed next to the battery will always measure the ______________________ current.

On the other hand, an ammeter which is placed on one branch will measure a ___________________ current.

If the currents from all branches are added up, it is the same as the __________________ current.

As more branches are added in parallel, the total current _____________________. but the current along any one branch stays the same.

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MYP9: The Building Blocks of Measurement Energy Transfers

What Makes a Current Flow?

Look at the diagrams above. Each diagram has a ball on a ramp – but why does the ball roll downhill in the diagram on the right?

The ball moves down hill because there is a force on it – in this case gravity.

We can also explain using ideas about energy. At the top of the ramp the ball has more gravitational potential energy – there is a change in the gravitational potential energy between the top and the bottom of the ramp.

On the diagram on the left there is no change in gravitational potential energy – so the ball does not move. As the ramp get steeper, the ball rolls down faster because the change in gravitational potential energy is greater.

Now look at the two diagrams below. Each diagram has a conducting wire and a charge inside it.

The charge moves through the wire because there is a force on it – in this case an electric force.

We can also explain using ideas about energy. On the left hand side of the wire the charge has more electric potential energy – there is a change in electric potential energy between the left and right hand sides of the wire.

On the diagram on the left there is no change in electric potential energy – so the charge does not move. On the diagram on the right hand side, a battery is connected. As the voltage across the wire increases, the charge moves faster because the change in the electric potential energy is greater.

3V

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MYP9: The Building Blocks of Measurement Potential Difference

Normally in a circuit we explain what is happening using the idea of potential difference.

The potential difference (or p.d.) is defined as; !

" ## $%&

' ( $)& # $ &

The p.d. is measured in volts – and is often called voltage as a result.

From the equation we can see that volts are the same as “Joules per Coulomb�.

The p.d. is equivalent to the “energy changed per coulomb of charge� or “energy per charge�.

Example 1 A charge of 20 C goes through a wire, so that 100 J of electrical energy is transferred into heat.

Calculate the voltage across the wire; %

' 100 )

5 ) 5 %

20

Example 2 50 C of charge passes through a wire which has a potential difference of 12V across it. Calculate the total amount of energy changed. ' % 12 % 50 600 )

Question A total of 600 J of electrical energy is transferred by a light bulb when a voltage of 12 V is applied. Calculate the amount of charge that has passed through the light bulb.

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MYP9: The Building Blocks of Measurement Potential Difference in Series

V 6V

P

Q

R

V

V

V

Build the circuit shown above with all 3 bulbs in it.

Place the voltmeter across bulb P. Record the reading.

Repeat for bulbs Q and R. Then place the voltmeter across the battery – record the reading.

Then write a conclusion for your results.

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MYP9: The Building Blocks of Measurement Potential Difference in Parallel 3V

P

V

Q

V

R

V

Build the circuit shown above with all 3 bulbs in it.

Place the voltmeter across bulb P. Record the reading.

Repeat for bulbs Q and R. Then place the voltmeter across the battery – record the reading.

Then write a conclusion for your results.

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MYP9: The Building Blocks of Measurement Checkpoint Energy

Increase

Divided

Total

Volts

Charge

p.d.

Decrease

Across

the same

through

Different

Use the words in the box above to answer the following question.

A voltmeter measures the ____________________ , or potential difference,________________ a component. The potential difference is measured in ____________________ and is equivalent to the __________________ per ____________________ . (1 volt = 1 Joule per Coulomb).

In a series circuit with several components (e.g. bulbs) the total voltage is ________________ between the components. The sum of the voltages across the individual components is equal to the ___________________ voltage. A voltmeter placed across the battery will also read the ______________ voltage. As more components are added in series, the voltage across any one component will ________________________

In a parallel circuit, the voltage across different loops or branches is _____________________.

As more branches are added in parallel, the voltage across each branch will be _____________________.as each branch acts independently from the other branches.

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MYP9: The Building Blocks of Measurement Resistance V

A

In the circuit above, the potential difference (p.d.) is V volts and the current through the ammeter is I amps. a) What would be the effect on the current of increasing the p.d.? b) What would be the effect on the current of adding more bulbs in series?

Every component in a circuit – like a bulb – has a resistance.

This means that resistance of a component is a measure of how difficult it is for the current to flow through it.

Resistance is measured in Ohms, symbol â„Ś. The formula is; +

+

%

%

So Ohms are equivalent to “Volts per Amp�. Notice that current is usually given the symbol I (it was originally called electric Intensity).

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MYP9: The Building Blocks of Measurement Working with Resistance

Use the formula on the previous page in the following calculations.

•

Find the unknown resistance X in circuits A and B.

•

Find the unknown currents Y in circuits C and D.

•

Find the unknown potential differences Z in circuits E and F.

A

B

V = 6.0V I = 0.2 A

V = 500V I = 5.0mA

X

X

C

D

V = 6.0V

V = 200V

Y

Y

12Ω

E

5kΩ

F

Z I = 1.2 A

Z I = 100µA

10Ω

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100 kΩ

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MYP9: The Building Blocks of Measurement Measuring Resistance

To measure the resistance of a component, you need to; •

Measure the current through and the p.d. across the component.

•

Use the formula. +

%

Experiment.

You need to; •

Build the circuit below. Set the power pack to 2 Volts.

•

Record the current on the ammeter and p.d on the voltmeter. Increase the dial setting on the power pack in steps, up to 12V.

•

Make a note of the uncertainty in the reading of the current and voltage – it will be at least half of the smallest division on each meter.

•

Then plot a graph of your results, including the uncertainties of your readings. Draw a smooth line of best fit through the data.

•

Write a conclusion for your experiment.

•

From your line of best fit, calculate the resistance at 5.0V and the resistance at 10.0 V.

•

In your conclusion, you must describe what happens to the resistance of the component.

•

Explain whether the current increases in direct proportion to the voltage or not.

0 - 12V

A

12 V Bulb

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MYP9: The Building Blocks of Measurement Measuring Resistance 0 - 12V

A

V

Experiment.

•

Build the circuit above using one of the resistors provided.

•

Set the power pack to 2 Volts.

•

Record the current and voltage on the meters. Increase the power pack in steps, up to 12V. Use a table like the one shown below.

•

Make a note of the uncertainty in the reading of the current and voltage – it will be at least half of the smallest division on each meter.

•

Then plot a graph of your results, including the uncertainties of your readings. Draw a smooth line of best fit through the data.

•

Repeat for the other two resistors.

•

Write a conclusion for your experiment.

•

From your lines of best fit, calculate the resistance at 5.0V and the resistance at 10.0 V.

•

In your conclusion, you must describe what happens to the resistance of the component.

•

Explain whether the current increases in direct proportion to the voltage or not

First Resistor p.d. /V Current / A

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MYP9: The Building Blocks of Measurement Resistances in Series

Answer these questions; a) In a series circuit, what happens to the (total) current when the number of components is increased? b) In a series circuit, what happens to the total voltage when the number of components is increased? c) From the formula for resistance; %

+

What happens to the total resistance R if the total voltage V remains constant and the total current I decreases? d) In series, the total voltage is found by adding up the individual voltages; %,-./0 % 1 %2 1 %3 1 ‌ + 1 +2 1 +3 1 ‌ $ + 1 +2 1 +3 1 ‌ & +,-./0 +,-./0 + 1 +2 1 +3 1 ‌ For identical resistors the formula becomes; +,-./0 + 1 + 1 + 1 ‌ + Where n is the number of resistors in series and R1 is the resistance of 1 resistor.

Now attempt the questions on the next page.

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MYP9: The Building Blocks of Measurement Resistance in Series

Calculate the unknown resistance X in circuits A and B, the unknown current Y in circuits C and D and the unknown voltage Z in circuits E and F.

A

B

V = 6.0V I = 0.20 A

V = 5V I = 5mA

X

20Ω

C

500Ω

D

V = 12V

X

V = 2kV

Y

Y

12Ω

E

5kΩ

6.0Ω

F

Z I = 1.2 A

10Ω

5kΩ

Z I = 100µA

40Ω

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100 kΩ

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50kΩ

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MYP9: The Building Blocks of Measurement Resistances in Parallel

Answer these questions; In a parallel circuit, what happens to the total current when the number of components is increased?

In a parallel circuit, what happens to the (total) potential difference when the number of components is increased?

From the formula for resistance; +

%

What happens to the total resistance R if the total voltage V remains constant and the total current I increases?

In parallel, the total current is found by adding up the individual currents; ,-./0 1 2 1 3 1 ‌

% % % 1 1 1 ‌ + +2 +3

% 5

1 1 1 1 1 1 ..6 + +2 +3

% 1

+,-./0

1

+,-./0

1 1 1 1 1 1 ‌ + +2 +3

For identical resistors the equation becomes simpler; 1

+,-./0

+,-./0

1 1 1 1 1 1 1 ‌ + + + + +

Where n is the number of resistors in series and R1 is the resistance of 1 resistor. Now attempt the questions on the next page.

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MYP9: The Building Blocks of Measurement Resistances in Parallel

Calculate the unknown current Y in circuits A, B and C and the unknown voltage Z in circuits D, E and F.

A

B

V = 2V Y

V = 50V Y

10Ω

200 Ω

5Ω

200 Ω

C

D

V = 6.0V

Z

I = 10 mA

Y 12Ω

5kΩ

12Ω

5kΩ

E

F

Z I = 1.2A

Z I = 10µA

10Ω

2 MΩ

10Ω

2 MΩ

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MYP9: The Building Blocks of Measurement Voltmeter Readings In the circuits below; •

Find the unknown resistances X in circuits A and B.

•

Find the unknown currents Y in circuits C and D.

•

Find the unknown voltages Z in circuits E and F.

•

Find the readings on each voltmeter.

A

B

V = 6V

V = 100V I = 0.06A

I = 0.5 A

V

V X

4Ω

C

1.2Ω

D

V = 5V

X

V = 400V

Y

Y

V 10Ω

E

V 1kΩ

10Ω

F

Z I = 1.5 A

3kΩ

Z I = 1mA

V 20Ω

V

60Ω

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1 kΩ

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5kΩ

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MYP9: The Building Blocks of Measurement More Circuits

Use the formula on the previous page in the following calculations.

•

Find the unknown resistance X in these circuits.

•

Find the reading on each ammeter.

A

B

V = 2V

V = 50V

A

I=0.2A

A 250 Ω

X

I=0.10 A X

5Ω

C

D

V = 6V

A

V=100V

I = 40 mA

I=10mA X

5kΩ

A 300Ω

E

X

F

V=9V I = 0.2A

V=1.5 V I = 15mA

90Ω

X

A

A 300Ω

X

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MYP9: The Building Blocks of Measurement More Difficult Circuits

A2 A1

V2

V1

In this circuit •

Each bulb has a resistance of 4.0Ω

•

Each resistor has a resistance of 2.0Ω

•

The battery supplies a voltage of 16.0V

Calculate the readings on each ammeter and voltmeter in the circuit.

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MYP9: The Building Blocks of Measurement More Difficult Circuits

A1

A2

V1

A circuit is constructed, as shown in the diagram above.

•

The bulb has a resistance of 3.0Ω

•

Each resistor has a resistance of 6.0Ω

•

The battery supplies a voltage of 12.0V

Calculate the readings on each ammeter and voltmeter.

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MYP9: The Building Blocks of Measurement Circuit Nightmares

V2

V1

A1

R2

V3

V5 A3

R1

A2

V4

In the circuit above; •

The resistance of each bulb is 3.0Ω

•

R1 = 2.0Ω

•

R2 = 5.0Ω

•

V4 = 10.0V

•

The two batteries are identical to each other.

Calculate the readings on each ammeter and voltmeter. Show all working.

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MYP9: The Building Blocks of Measurement Practise Questions

A

The current through a lamp was measured in the circuit above and results recorded in the table below.

Reading

1

2

3

4

5

Current / A

0.21

0.25

0.30

0.22

0.24

a) The average current through the lamp is; A 0.24 A B

0.12 A

C

1.22 A

D

0.244 A

b) The uncertainty in the readings of the current, expressed as a percentage, is approximately; A 9.0% B

4.5%

C

18%

D

37%

c) The resistance of the lamp, under normal conditions, is 50â„Ś, and the voltage supplied is 12.0V. Therefore the current through the lamp should be approximately A 4.1 A B

0.24 A

C

620 A

D

2.4 A

d) The measurements of the current could be described as; A Precise but not accurate B

Accurate but not precise

C

Not precise and not accurate

D

Both precise and accurate

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MYP9: The Building Blocks of Measurement Practise Questions e) The unit of resistance is the Ohm (Ω). The unit of Ohms is equivalent to ;

f)

A

Volts per Amp

B

Amps per Volt

C

Joules per Coulomb

D

Coulombs per Joule

and g).

A student is given 3 identical 30Ω resistors to use in a circuit. They are the only components that have any resistance in the circuit.

Using all 3 resistors, the smallest possible value of the resistance for the circuit is; A

3Ω

B

10 Ω

C

30 Ω

D

90 Ω

g) Using just these 3 resistors, it is possible to have a total resistance of; A

0Ω

B

5Ω

C

15 Ω

D

45 Ω

h) measurement can be said to be precise if; A

It agrees with the true value.

B

It has a small uncertainty.

C

It is accurate.

D

Many readings are taken.

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MYP9: The Building Blocks of Measurement Practise Questions

i) The grid below shows one data point and its associated error bar on a graph. The x-axis is not shown.

5.0 4.0 3.0 2.0 1.0 Which of the following is the correct statement of the y-value of the data point, with its uncertainty?

j)

A.

3.0 ± 0.1

B.

3.0 ± 0.2

C.

3.0 ± 0.4

D.

3.0 ± 0.05

A student measures the period of a pendulum several times. The readings are given in the table below.

Period /s

1.44

1.73

1.49

1.41

1.55

The average period , based on these results, is, to the correct number of significant figures; A.

1.524 s

B.

7.62 s

C.

1.52 s

D.

6.38 s

k) From the pendulum data above, the uncertainty in the average value is; A.

±0.08 s

B.

±0.04 s

C.

±0.32 s

D.

±0.16 s

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MYP9: The Building Blocks of Measurement Practise Questions

4Ω X

Y

A 8Ω

V

In the circuit above, the current potential difference between X and Y is 8.0 V. l)

The potential difference across the 8Ω resistor is; A

2.0 V

B

4.0 V

C

8.0 V

D

16.0 V

m) The current through the 4 Ω resistor is; A

0.5 A

B

1.0 A

C

2.0 A

D

4.0 A

n) The resistance between points X and Y is approximately; A

0.3 Ω

B

0.6 Ω

C

2.7 Ω

D

4.0 Ω

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MYP9: The Building Blocks of Measurement Practise Questions

Complete the table below using the Ohm’s Law formula; Q

Potential Difference

Current

Resistance

1

3.0 mV

6.0 µA

2

300 kV

50 A

3

150 nV

30 Ω

4

230 V

20Ω

5

25 µA

5.0 kΩ

6

50 mA

1.0 MΩ

Complete the table below using the formula for Charge; Q

Charge

Current

Time

1

100 nC

25 µA

2

65 MC

5.0 A

3

35 kC

6.0 ms

4

50 µC

25 µs

5

25 µA

5.0 ms

6

75 mA

1.0 ns

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MYP9: The Building Blocks of Measurement Practise Questions

What is the total resistance of… a) Five 10Ω resistors in series? b) Five 10Ω resistors in parallel? c) Two 50Ω resistors in parallel, in series with a third 50 Ω resistor? d) Four 8Ω resistors in parallel, in series with another four 8Ω resistors in parallel?

What is the (total) current through… a) A resistance of 200Ω if the p.d. across it is 250 mV? b) Two 50 Ω resistances in series if the p.d. across the two of them is 5.0 V? c) Two 30 Ω resistances in series if the p.d. across one of them is 6.0 V? d) Three 12 Ω resistors in parallel if the p.d. across one of them is 12 V? e) Two 12 Ω resistors in parallel, in series with a third 12 Ω resistor, if the p.d. across all three resistors together is 6.0 V?

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MYP9: The Building Blocks of Measurement Word Search L

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Words ACCURACY

AMPERE

AVERAGE

COULOMB

CURRENT

ELECTRICITY

JOULE

LINE OF BEST FIT

OHM

POTENTIAL DIFFERENCE

PRECISION

RANGE

RESISTANCE

UNCERTAINTY

VOLTAGE

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MYP9: The Building Blocks of Measurement Cross Word

Across

Down

2. A device that measures current.

1. When electrical components are arranged in several loops or branches.

5. When electrical components are arranged in one loop.

3. A device that measures potential difference.

9. The highest value minus the lowest value in a 4. The charge per second passing a point repeated set of measurements.

10. If the range of values from a measurement is small then the measurement is ______

6. The ratio of voltage to current.

7. Half of the range.

8. A measurement is accurate if the value is close to the _______________ value.

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MYP9: The Building Blocks of Measurement Traffic Lights

â˜ş

No.

Question / Statement

1

I know the fundamental units of measurement.

2

I can give examples of derived units of measurement.

3

I can convert quantities from one unit to another

4

I know what is meant by independent, dependent and controlled variables.

5

I can design an experiment to investigate the effect of one factor.

6

I can calculate the average, range and uncertainty of a quantity.

7

I can represent the average and uncertainty on a graph.

8

I can draw an appropriate line of best fit and use it to make a conclusion.

9

I know what precision and accuracy are and can calculate their values.

10

I can describe what happens to the current in series and parallel circuits as more components are added.

11

I can describe what happens to the potential difference in series and parallel circuits as more components are added.

12

I can calculate current, potential difference and resistance in series and parallel circuits.

13

I know how electricity is transmitted to homes and buildings.

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VIS Science Department

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MYP9: The Building Blocks of Measurement Self Reflection What I liked about this Unit

What I disliked about this Unit.

What we could change to make the Unit better.

How useful I found this Unit.

Additional Comments

G9 Physics - The Building Blocks of Measurement Aug2013

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VIS Science Department

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MYP9: The Building Blocks of Measurement Learner Profile

In this Unit where did you get the opportunity to develop being I asked questions or performed research about…

Inquirer I showed my understanding and knowledge when …

Knowledgeable I had to think a lot about….

Thinker I communicated best when…

Communicator I showed I was fair when….

Principled I accepted different points of view when…

Open-minded I looked after my classmates and/or the environment when…

Caring I was nervous about….

Risk taker I felt most positive in this unit when….

Balanced I learned best when I …

Reflective

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