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Junior Cert Science
Numeracy Resources
Let’s Talk About Measurement
Measurement of Time Directions:
Put a < (less than), > (greater than), or = symbol between the two
amounts of time. Unit
Is equal to
1 Year
365 days
1Day
24 Hours
1 Hour
60 Minutes
1 Minute
60 Seconds
a) 1 minute
45 seconds
b) 1 hour
60 minutes
c) 1 year
15 months
d) 4 days
1 week
e) 20 minutes
3 hours
f) 1 day
12 hours
g) 453 L
453 mL
h) 83 millimeters
9 meters
i) 50 centimeters
5 meters
j) 12 seconds
1 hour
SI Unit for Time is the Second
Let’s Talk About Measurement
Measurement of Length What piece of equipment would you use to
Mark out the distance for the 100M race on sports day?________________
Find the area of a room?______________________________________________
To find the thickness of a book?_______________________________________
Measure the diameter of pipe?________________________________________
Measure the length of a table?________________________________________
Measure the distance between two cities on a map?__________________
Height
Unit
Unit
Is equal to
My height is
1 km
1000M
My partner’s height is
1M
100cm
1cm
10mm
Our Average height is
Wrap a piece of string around your wrist. Cut it at the point where they
meet. Now measure the string next to a meter rule.
Body part
Wrist
Length (cm) or (mm)
Ankle Head SI Unit for Length is the Metre
Let’s Talk About Measurement
Measurement of Volume
Volume is the amount of space that an object
takes up VOLUME can be used to study amounts of…

LIQUIDS (water, milk, juice)

GASES (air, oxygen, helium)

SOLIDS (flour, sugar, blocks of wood)
Unit
Symbol
Cubic Metre
M3
Litre
L
Cubic Centimetre
cm3
Millilitre
mL
Using this information complete the following statements:
1 teaspoon = 5mL
1 tablespoon = 15mL
1 (measuring) cup = 250mL
How many teaspoons of water fit in 1 tablespoon?
15mL ÷ 5mL = 3
So, there are _______ teaspoons in a _______________________.
How many teaspoons of sugar will fit in 1 cup?
250mL ÷ 5mL = 50
So, there are _______ teaspoons in a ______________.
How many teaspoons of milk are there in a 1L carton? 1000mL ÷ 5mL = 200
So, there are _________ teaspoons in 1 ____________.
Example
Find the volume of juice in a box that is 5cm long, 3cm wide, and 10cm high.
V=LxWxH
= 5cm x 3cm x 10cm
= 150cm³ NOTICE THE FOLLOWING ABOUT THIS ANSWER:
the units are now CUBED (cm³) – This exponent (3)must be used whenever
we calculate the VOLUME using the L, W and H!
What does this have to do with OTHER units of VOLUME (mL, L, etc.)?
Well…
1cm³ = 1mL so 150cm3 = 150mL
SI Unit for Volume is the Metre3
Let’s Talk About Measurement
Measurement of Volume
Formula: Volume = L x W x H
Question 1:
A letter 'T' shape is made by sticking together 2 cuboids as shown in the diagram.
What is the total volume in cm³ of the letter 'T'?
Question 2:
Calculate the volume of each of the following cuboids :
SI Unit for Volume is the Metre3
Let’s Talk About Measurement
Measurement of Volume
Formula: Volume = L x W x H
Question 1:
Calculate the volume of the cardboard box. If
the box was sealed could it be used to hold 85L of
sugar? Explain your answer
Question 2:
Find the volume of air in an room that is 15m long, 8m
wide and 3m high.
If you needed an air conditioning unit to cool this room
should you buy this one that was on special offer?
Question 3:
How many 250mls can of lemonade will it take to fill a 4L jug for your party?
Question 4:
A rectangular hot tub measures 100cm high x 200cm long x 200 cm wide. How many
litres of water will it take to fill the hot tub?
Question 5:
(i) The diagram shows a piece of equipment, labelled A,
containing water.
a)
Name A.
b)
What is the volume in A?
(ii) A stone was then added and a new volume was
recorded as shown in B.
a)
What is the volume in B?
b)
What was the volume of the stone in cm3?
c)
What is the curve on the top of the water called?
d)
Name a second item of laboratory equipment which
enables more accurate measurements of volume to be
made
e)
What other piece of laboratory equipment can be used to measure volume?
SI Unit for Volume is the Metre3
Let’s Talk About Measurement
Measurement of Density
Density = Mass
Volume Q1
Complete the following sentence by putting in words from the list below:
The density of an object is found by dividing the ___________ of an object by its
________.
Area
Volume
Length
Mass
Acceleration.
Q2
A regular block of glass has a length of 4cm, width of 3cm and a height of 2cm.
Calculate the volume of the block of glass?
This block of glass was placed in a graduated cylinder which already had 50cm3 of
water in it. Underline in the following list the new level of water after the block of
glass was added.
59cm3
24cm3
74cm3
98cm3
Q3 Will a ship sink further in saltwater or freshwater
Q4 How could you prove that a barman was watering down the whiskey without
you having to drink any of it?
Q5 A block of iron or steel will sink if put into water most of the ships in the world are
made of iron and steel and they float. Can you explain this?
Q6 The mass of an object is measured in ___________.
Q 7 Density is measured in _________ ________.
Answer the following questions using the table below:
Q8 Put these objects in the correct order starting with the most dense.
Q9 In the diagram below which substance is the most dense.
Q10 The density of some metals are as follows, using this information find out which
metal would sink in mercury.
Density
Mercury
Lead
Gold
Iron
13.6g/cm3
11.2g/cm3
19.3g/cm3
7.9g/cm3
SI Unit for Density is the Kg/Metre3
Let’s Talk About Work, Energy and Power
Work, Energy and Power
Energy is the ability to do Work Work done = Force × distance
Power is the rate at which work is done
Q1: How much work is done when a force of 10N moves and object 20M?
What is the formula you will use?
What values will you insert
Q2: A 60 watt light bulb runs for 5 seconds. How much energy does it use?
What is the formula?
What is the unit of energy?
Q3: Stephen runs up a 3 meter high flight of stairs. His mass is 60kg.
How much work did he do?
How much energy did he use?
What are the units for work?
What are the units for energy?
Q4: On a recent adventure trip, Anita went rock-climbing. Anita was
able to steadily lift her 70kg body 20.0 meters in 100 seconds.
Determine Anita 's power during this portion of the climb.
How do you calculate the force?
How do you calculate the work?
What is the formula for power?
Q5: A physics teacher owns a family of squirrels. The squirrels have
been trained to do push-ups in a repetitive fashion. Being
connected to an electrical generator, their on going exercise is
used to help power the teacher’s home.
There are 23 squirrels in the family and their average mass is 1.0 kg.
They do work on the "up" part of the push-up, raising their body an
average distance of 5.0 cm.
If the squirrels averages 70 push-ups per minute, then determine
the total amount of work done in one minute and the power
generated by their activity.
Quantity
Unit
Work
Joule
Energy
Joule
Power
Watt
Power
Energy × Time
Let’s Talk About Electricity
Electricity Quantity
Symbol
Unit
Symbol
Measured with
Current
I
Amps
A
Ammeter
Potential
difference
V
Volts
V
Voltmeter
Resistance
R
Ohms
Ω
Ohmmeter
Symbol
Relationship between current, potential difference and resistance
V = RI
Q1: This circuit was used to take measurements of current through the resistor and
voltage across the resistor. The following measurements were obtained. Plot a
graph of these measurements. What mathematical relationship do you see
between voltage and current in this simple circuit?
Q2: Calculate the resistance of a resistor when 20 V produces a current of 4 A.
Q3: . What is the current through a 40-ohm resistance that has a potential
difference of 160 volts?
Q 4: If the headlight on your car has a resistance of 30 ohms and the car battery
put out 12 V, what is the current through the headlight circuit?
Q5: The motor for your electric car is attached to a generator. The motor has a
resistance of 30ohms and the current is 4 amperes (A). What is the generator’s
voltage?
Q6: If a clock radio uses 2 x 10 –4 A of current when you run it on a 9 V battery,
what resistance is its circuit providing?
Let’s Talk About Electricity
Electricity Q1: Match the quantity on the left to the unit in which it is measured on
the right.
Q2: A resistor of 8 has a potential difference of 4 V between its ends.
Calculate the current passing through the resistor?
Q3: A 220 volt wall outlet supplies power to a strobe light with a
resistance of 2200 ohms. How much current is flowing through the
strobe light?
What are you trying to find?
Write the formula that you will use.
Insert the values for the formula
Calculate and write you answer
Q4: A CD player with a resistance of 40 ohms has a current of 0.1 amps
flowing through it. Calculate how many volts supply the CD player.
Choose your answer below
1. 0.0025 volts
2. 4.0 volts
3. 10.0 volts
4. 400.0 volts
Q5: A 220-volt power source supplies a lamp with a resistance of 192
ohms. What is the current flow of the circuit?
What are you trying to find?
Write the formula that you will use.
Insert the values for the formula
Calculate and write you answer
Q6: What is the resistance of the circuit conductors when the voltage is
12 volts and the current flowing through the conductors is 2 amperes?
Let’s Talk About Electricity
Cost of Electricity Q1: The kilowatt-hour is the unit of electrical energy used
by electricity suppliers.
The photograph shows a kWh (kilowatt-hour) meter. This
meter is connected into the electricity consumer’s
domestic circuit and it can measure energy consumption
a selected part of the circuit, the total energy used and
cost it. The meter can be wall-mounted in a convenient
place.
Give two advantages to the consumer of having this type
of meter.
Define the Watt, the unit of power.
Calculate the cost of using of using the electric kettle, shown
in the diagram, for ten hours if a unit of electricity costs 15
cent.
Q2: A 20 W (0.02 kW) CFL bulb is equivalent to 115 W (0.115 kW) incandescent bulb.
Electricity costs 15 cent per kW h.
Calculate the cost of using each of these bulbs for 100 hours.
Q3: Nikola Tesla (1856-1943) showed at the Frankfurt
Fair in 1891 that alternating current could be
transmitted over much longer distances than direct
current. This is why the electricity supply to our
homes is alternating current.
Distinguish between alternating and direct current.
What is the average voltage of domestic alternating current in
Ireland?
Q4: Components, e.g. bulbs, in electrical circuits can be connected in series or in
parallel.
(i) It is noticed that, when one headlight fails (blows) in a car, the second remains
lighting. State the way the headlights are connected and give a reason why this
mode of connection is used.
(ii) All of the bulbs go out in an old set of Christmas tree lights, when one
of bulbs fails (blows). In what way are the bulbs connected in this set of
lights? Explain why, when one bulb blows, they all go out.
(iii) Calculate the resistance of the filament of a
car headlamp when 12 V produces a current of 5 A in it.
In what unit is resistance measured?
in
Let’s Talk About Force
Moment of Force =
Force x Perpendicular distance
Q1: Each force and distance from the fulcrum on the left causes a certain
moment. Draw a straight line from each force and distance from the
fulcrum on the left with its corresponding moment on the right.
Q2: What is the moment of each of these force ?
2 metres
pivot
6 Newtons
1.5 metres
pivot
3 Newtons
Q3: The car tyre has a puncture. So you need to take off the tyre to put
a new one on. Your friend offers you a choice of spanners.
Spanner A is 10 cm long. Spanner B is 20 cm long. Spanner C is 30 cm
long. Which spanner would require the least force to use?
Q4: Find out, by calculating the moments of force on each side, which
of the following are balanced.