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Unit 2 Classifying in Physics
1. Discussion points – classification.
a) How could you classify students in this class or school? According to …
b) What are some ways you could classify foods? clothes? cars? schools? films?
cities? academic subjects? animals? jobs? people in your town or country? music?
c) A nutritionist might be interested in classifying food according to calories,
cholesterol content, sugar content etc. What type of classification might interest a
biologist? A meteorologist? A psychologist? A police detective? A football
player?
d) What about a physicist? What can you classify in physics?
2. CLASSIFYING MATTER. Read the following passage. Then classify the
matter, using the information in the text.
State of matter
(From: Wikipedia, the free encyclopedia)
States of matter are the distinct forms that different phases of matter take on. Solid, liquid
and gas are the most common states of matter on Earth. However, much of the baryonic
matter of the universe is in the form of hot plasma, both as rarefied interstellar medium and as
dense stars.
Historically, the distinction is made based on qualitative differences in bulk properties. Solid
is the state in which matter maintains a fixed volume and shape; liquid is the state in which
matter maintains a fixed volume but adapts to the shape of its container; and gas is the state in
which matter expands to occupy whatever volume is available.
The state or phase of a given set of matter can change depending on pressure and temperature
conditions, transitioning to other phases as these conditions change to favor their existence;
for example, solid transitions to liquid with an increase in temperature. A phase transition
indicates a change in structure and can be recognized by an abrupt change in properties.
More recently, distinctions between states have been based on differences in molecular
interrelationships. Solid is the state in which intermolecular attractions keep the molecules in
fixed spatial relationships. Liquid is the state in which intermolecular attractions keep
molecules in proximity, but do not keep the molecules in fixed relationships. Gas is the state
in which molecules are comparatively separated and intermolecular attractions have relatively
little effect on their respective motions. Plasma is a highly ionized gas that occurs at high
temperatures. The intermolecular forces created by ionic attractions and repulsions give these
compositions distinct properties, for which reason plasma is described as a fourth state of
matter.
Forms of matter that are not composed of molecules and are organized by different forces can
also be considered different states of matter. Superfluids (like Fermionic condensate) and the
quark–gluon plasma are examples.
MATTER
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3. Speaking. Work in pairs.
Describe the diagram that you have drawn, using the typical classifying
vocabulary:
Matter
is/are
may be
can be
could be
classified
grouped
divided
arranged
categorized
into
divisions
groups
types
classes
categories
classifications
classified
categorized
classed
grouped
as
solid, liquid, or
gas
There are (three/ four/ many)
types
kinds
classes
categories
of matter
Oxygen is
a type
a kind
a form
an example
of gas
Everything is made up of
is composed of
consists of
matter/ molecules
Different states of matter include
comprise
Superfluids and the quarkgluon
plasma
4. Look at the picture and label all the phase transitions (according to arrows)(from:
www.wikipedia.org)
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5. Video (http://www.youtube.com/watch?v=qJRxYBIfZlE&feature=related – states of matter, changes in state)
Before you watch: check the vocabulary below:
occur to turn into vapour to make up evaporation melt bound rigid hollow
mist sublimation
Watch and answer the questions below:
a) What are bubbles of water made up of?
b) At what temperature do liquids change into gas?
c) What is the melting point of a substance?
d) What is the average temperature at which rock melts?
e) Why is water different from most liquids?
f) How can it be explained?
g) Describe dry ice and its possible states.
6. GRAMMAR REVISION - passive voice
I. Look at the sentences from the lesson:
1. Matter can be classified as solid, liquid & gas.
2. A considerable force would be needed to change the shape of an iron bar.
3. Crystalline solids are arranged in a definite pattern.
4. When they are heated, they melt.
5. If water is poured on the table...
What is the general pattern of a passive sentence?
subject + ___________+____________
Do they say what happens to the subject? (matter, force, solids, etc.)
Do the underlined phrases say who/what performs action?
Are the sentences formal or informal?
II. Rewrite the sentences using passive voice.
1. We can classify matter according to different criteria.
2. The government will build a road right outside her front door.
3. His professors were discussing his oral exam right in front of him.
4. My colleagues are attending a seminar at the moment.
5. Corrosion has damaged the hull of the ship.
6. John Logie Baird transmitted the first television picture in 1925.
Rewrite the sentences using active voice.
1. The lecture will be delivered by Professor Pierce.
2. These books had been left in the classroom by a careless student.
3. Coffee is grown in many parts of Hawaii by plantation workers.
4. The "Theory of Relativity" was developed by Albert Einstein
5. The streets around the fire had been blocked off by the police.
6. A great deal of our oil will have been exported to other countries by our government.
III. Think about rules or regulations in our class/ university/ students residence halls/
public transport/etc. and write 5 sentences in the passive voice, e.g.: Mobile phones have
to be switched off
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7. Reading comprehension
Complete the text with the clauses below:
a) that can be recognised by their different properties
b) that result in a change of identity
c) without changing its chemical identity
d) because there is some observable change
e) hydrogen and oxygen are chemically combined
f) is classified as a chemical property
g) that do not change chemical identities
Changes in matter: Is it physical or chemical?
Sulphur is yellow; iron is magnetic; water boils at 100°C. These are different properties of
matter, but with something in common. We can observe the colour of a substance, pick it up with a
magnet, measure its boiling point or determine its mass (1) _________ . Such properties are classified
as physical properties. In chemistry, the word physical is used to refer to processes
(2) _________ . Separating sulphur and iron with a magnet is a physical separation. Boiling water is a
physical change – the steam that forms is still water (H2O).
By contrast to physical changes such as boiling, there are processes that do result in changes of
identity. When gasoline burns, it is converted to a mixture of carbon dioxide, carbon monoxide, and
water. Burning in air, a property that gasoline, kerosene, and similar substances have in common,
(3) _________.
The word chemical is used to describe processes (4) _________ . The combination of
hydrogen and oxygen to form water is a chemical change or chemical reaction – a process in which
one or more substances (the reactants, which can be elements or compounds, or both) are converted
to one or more different substances (the products, which can also be elements or compounds, or
both).
A chemical reaction produces a new arrangement of atoms. The number and kinds of atoms in
the reactants and products remain the same, but the reactants and products are different substances
(5) _________ . To distinguish between a hydrogen-oxygen mixture and a compound composed of
hydrogen and oxygen, we might say that in water, (6) ______. The meaning is that the hydrogen and
oxygen atoms are held together strongly enough to form the individual units we call water molecules.
Some easily observed results of chemical reactions are the rusting of iron, the change of leaf
colour in the fall, and the formation of carbon dioxide bubbles by an antacid tablet. Often, though not
always, the occurrence of a chemical reaction can be detected (7) _______ .
(adapted from Joesten Castellion, Hogg The World of Chemistry. Thomson Brooks/Cole: 2007.)
Vocabulary:
matter (n) – hmota
solid (n/adj) - pevná látka,
pevný
liquid (n/adj) - kapalina,
kapalný
gas (n), gaseous /adj.) – plyn,
plynný
property (n) - vlastnost
rarefied – řídký
dense –hustý
based on – vycházející z, založený na
to maintain – udržovat, zachovávat
to adapt – přizpůsobit se
to expand – rozšířit (se), roztáhnout, rozrůst
to occupy – zabírat, zaplnit
transition – přechod
to indicate – naznačovat
abrupt – náhlý, prudký
interrelationship – vzájemný vztah
in proximity – v blízkosti
repulsion – odpor, odpuzování
be composed of – skládat se z…
to consider – považovat, pokládat
gluon – hypotetická neutrální částice pojící vzájemně
kvarky
to occur – nastat, vyskytovat se
evaporation – vy-/odpařování
to pull apart – roztrhnout, odtrhnout od sebe
boiling point – bod varu
melting point – bod tání
freezing point – bod tuhnutí
on average – průměrně
tied up – svázaný
exception – výjimka
volume – objem
rigid – tuhý, pevný
hollow – dutý, prázdný