# 2.1 UNIT Questions

Urban and Civil

Nov 26, 2013 (4 years and 5 months ago)

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2.1
UNIT
Questions

Revision questions

Scientific models

1
What is a ‘model’ in science?

2
Which type of modelling would be most useful for scientists who want to:

a
build a ship with a brand new shape of hull?

b
understand the structure of deep inside
the Earth, where no one has ever been?

c
predict the damage that would happen to a city due to a cyclone?

The particle model

3
List the three phases of matter.

4
List five different examples of:

a
solids

b
liquids

c
gases.

5
Name a food or drink that
contains:

a
solid and liquid material

b
liquid and gas.

Solids

6
Copy the following, correcting any incorrect statements to make them true.

a
Solids can be compressed.

b
The particles in a solid move a lot.

c
Particles vibrate slower when heated.

7
What h
appens to the bonds between particles when heat is applied?

Liquids

8
State three things the particle model says about liquids.

9
Why is diving into a swimming pool easier than into a block of ice?

Gases

10
What property makes gases useful for shock
absorbers in mountain bikes and cars?

11
Which has the most heat energy

ice, liquid water, or steam?

12
Smells don’t really disappear. Explain.

Evidence for the particle model

13
What is Brownian motion?

14
Do the sugar particles really disappear when we
dissolve sugar in a cup of tea? How can you tell?

15
How does the fragrance of a perfume travel throughout a room?

16
You smell fried onions on a BBQ. What particles must be reaching your nose?

Thinking questions

17
What do:

a
solids and liquids have in
common?

b
liquids and gases have in common?

18
Give one key difference between:

a
a solid and a liquid

b
a liquid and a gas

c
a solid and a gas.

20
List the different states of matter involved in the various stages of cooking frozen French fries.

21
Draw

your own version of the particle model in three layers. Put the solid at the bottom, gradually changing into liquid and
finally with gas at the top.

22
How can foam rubber be compressed when solids are supposed to be incompressible?

23
There must be som
e bonds or attractions, however weak, between the particles in a liquid. Explain why.

2.2
UNIT

Questions

Revision questions

Solid to liquid

1
What is the name given for the change of a solid into a liquid.

2
What is meant by ‘melting point’?

3
Where do
ice cubes get their energy from when they are in an Esky full of soft drinks?

4
Explain why a candle doesn’t melt on a hot day.

Liquid to solid

5
What is this change called: liquid

solid.

6
What is another word for ‘freezing’?

7
Predict the freezing
point of:

a
liquid water

b
molten candle wax.

Liquid to gas

8
Give another term for ‘evaporation’.

9
What is the difference between evaporation and boiling?

10
What is the boiling point of water?

11
Predict the maximum temperature of liquid water.

Gas to

liquid

12
What is condensation?

13
The bathroom mirror often fogs up on a cold morning. Explain why.

Solid to gas

14
Identify two substances that sublime.

15
What produces the fog on stage and in films?
kiquestions

16
Identify three changes of state that
occur around home.

17
What is the opposite to:

a
melting?

b
condensation?

2.3

UNIT

Questions

Revision questions

Particles and expansion

1
Give another word for:

a
getting bigger

b
getting smaller.

2
Copy and complete: Substances generally __________ when

heated and __________ when cooled.

Expansion of solids

3
When a solid is heated, what happens to the vibration of the particles?

4
How much will 1 metre of the following substances expand if heated 10ºC?

a
Concrete

b
Aluminium

5
One metre of the
following substances is heated 100ºC. How much will they expand?

a
Iron

b
Glass

6
What is an expansion gap and what is its purpose?

7
Draw a diagram to show how a bimetallic strip can be used as a switch.

Expansion of liquids

8
Suggest why mercury or colo
ured alcohol are used in thermometers instead of coloured water.

9
Why is the tube of a thermometer so narrow?

10
Explain why a petrol tank must never be filled right to the top.

11
Between which temperatures does water do the opposite of what other substa
nces do?

Expansion of gases

12
Non
-
explosive helium gas is about to be heated. What would happen if it was in:

a
a tied balloon?

b
a sealed steel tank?

Thinking questions

13
Out of solids, liquids and gases, which expand:

a
most when heated?

b
least when
heated?

14
Figure 2.3.12 shows a solid in terms of the particle model. Which diagram in Figure 2.3.13 best shows he solid after
heating?

15
Give an example where expansion could be damaging.

16
Explain why concrete is reinforced with steel rods and
not brass rods.

17
List the following in order from least to greatest expansion when heated: concrete, Pyrex, brass and

platinum.

18
Which type of bimetallic strip would bend most when heated

one made of iron and brass, or one made of iron and
aluminium?

19
Using the information in the table on page 47, accurately draw a bar graph comparing the expansion of different
substances when heated 10ºC.

20
A light globe is made of glass with a platinum filament. What do you notice about the expansion ability of

these
substances? Why is this important?

21
Suggest why Invar is used to make accurate technical instruments.

22
Why is it more important to have a constriction in a clinical thermometer than in a laboratory one?

23
Why do you think a clinical thermome
ter is usually shaken after use?

24
Explain how fish can survive when a lake freezes.

25
Explain why concrete footpaths and driveways need ‘lines’.

26
Some barbecue hot plates make sounds when first heated and when they begin to cool down. Suggest why?

27
Using the table on page 47, predict how much the following substances would expand.

a
1 m glass rod, heated 1ºC

b
1 m Invar rod, heated 200ºC

c
1 m Pyrex rod, heated 30ºC

d
2 m steel rod, heated 10ºC

e
3 m platinum rod, heated 100ºC

f
10 m wooden beam,

heated 10ºC

2.4
UNIT

Questions

]

Revision questions

Density and packing

1
Compare a tonne of gold with a tonne of sawdust. Which would:

a
weigh more?

b
take up more space?

c
have the least density?

d
be most likely to float on water?

2
Use Figure
2.4.1 to find the densities of:

a
water

b
wood

c
copper

d
gold.

Calculating density

3
State the technical definition for density.

4
Calculate the density of a type of rubber if a piece of it has a mass of 75 grams, and a volume of 50 cm
3
.

5
What is the
volume of a block of glass of length 4 cm, width 2 cm and height 3 cm?

6
Find the volume of the brick in Figure 2.4.7.

7
Find the volume of the stone shown in Figure 2.4.8.

8
If the mass of the stone in Figure 2.4.8 is 32 grams, what is its density?

Floating and sinking

9
List the substances in Figure 2.4.1 that would float in water and those that would sink.

10
Oil floats on water. How does the density of oil compare with the density of water?

11

12
Give three examples whe
re air is pumped in and out to change density.

Thinking questions

13
Ice floats on pure water and even better on seawater. Compare the densities of ice, water and seawater.

14
Is the hot air in a room near the ceiling or the floor? Use your answer to comp
are the densities of hot and cold air.

15
Perspex has the same density as cooking oil, but a lower density than water. Draw a diagram showing what would
happen if all three are placed in the one beaker.

16
How can steel
-
hulled ships float when steel is
denser than water?

Analysis questions

17
What would be the mass of 4 cm
3
of gold?

18
Two blocks of wood

one oak and the other cedar

have the same volume, but the cedar block has less mass than the
oak. What can you say about the densities of oak and
cedar?

19
A lump of brand A concrete has the same mass as a lump of brand B concrete, but the brand B lump has less volume.
Which is denser?

20
A piece of metal has a mass of 6 grams and a volume of 2 cm
3
. What is the density of the metal?