3. CHANGE OF STATE
•When substances are heated or cooled, they undergo
changes in their state of matter. The common changes of
state include:
Melting (Solid to Liquid):
• Heating a solid substance causes its particles to gain energy and
vibrate more rapidly.
• Eventually, the particles overcome the forces holding them in a
fixed position, causing the solid to melt and transform into a liquid.
• Example: Ice melting into water when heated.
4. Freezing (Liquid to Solid):
• Cooling a liquid substance causes its particles to lose energy and slow
down.
• As the particles lose energy, they form regular arrangements and bond
together more closely, resulting in the liquid solidifying into a solid.
• Example: Water freezing into ice when cooled.
Vaporization (Liquid to Gas):
• Heating a liquid substance increases the energy of its particles further,
causing them to move more rapidly.
• Eventually, some particles gain enough energy to overcome the forces
of attraction between them and escape from the liquid surface, forming
a gas.
• Vaporization includes two processes: evaporation (slow process at the
surface) and boiling (rapid process throughout the liquid).
• Example: Water boiling and turning into steam when heated.
5. Condensation (Gas to Liquid):
• Cooling a gaseous substance causes its particles to lose energy and slow
down.
• As the particles lose energy, they come closer together and form liquid
droplets.
• Condensation typically occurs when the temperature of the gas decreases or
when the gas comes into contact with a cooler surface.
• Example: Steam condensing on a mirror or window when cooled.
Sublimation (Solid to Gas):
• Some substances can undergo sublimation, where they transform directly
from a solid to a gas without passing through the liquid state.
• Sublimation occurs when the vapor pressure of the solid exceeds
atmospheric pressure at a certain temperature.
• Example: Dry ice (solid carbon dioxide) sublimating into carbon dioxide gas
when exposed to room temperature.
6. Deposition (Gas to Solid):
•Deposition is the reverse process of sublimation, where
a gas transforms directly into a solid without passing
through the liquid state.
•This occurs when gas molecules lose energy and come
together to form a solid.
•Example: Frost forming on a surface in cold weather,
where water vapor in the air directly transforms into ice
crystals
7. ACTIVITY
•carry out activities to demonstrate change of state
of matter (melting, evaporation, sublimation,
condensation, freezing, deposition) collaboratively,
•Note: observe safety while heating substances to avoid
fires and burns,
8. With peers Discuss the applications of change of state of matter in
everyday life including
• Cooking and Food Preparation
• Refrigeration and Preservation
• Cleaning
• Manufacturing and Industrial Processes
• Personal Care and Beauty
And report to the class
9. EXTENDED ACTIVITY
•Make candles using waste candle wax or beeswax
•Make a recording of yourself as you repair broken
plastic containers.
11. COMPOSITION OF AIR
Components of air in the atmosphere
•Air is a mixture of many gases
•The components of air are
•1. Nitrogen gases
•2. Oxygen
•3. Carbon dioxide
•4. Noble gases
•• Air also contains water vapour and dust
14. MIXTURE OF GASES
• Air is made up of various
• gases as listed:
• • Nitrogen (78%)
• • Oxygen (21%)
• • Carbon dioxide
• (0.03%)
• • noble gas (0.97%)
15. USES OF DIFFERENT COMPONENTS OF AIR
USES OF OXYGEN
• a) BREATHING
• • All living things need air
• • When we breathe in air, the body use oxygen present in the air
• • Oxygen is needed in our bodies to combine with food to produce energy.
• • Oxygen is used in hospitals to help patients with breathing difficulties
• • Deep seas divers carry oxygen tanks tied to their back which help them breathe under
water.
b) BURNING/COMBUSTION
• - Oxygen is used in burning.
• - Fuels e.g. charcoal, petrol cannot burn without oxygen.
• - The burning candle in the diagram below has used oxygen in the glass forcing water to rise
in the glass by a fifth.
16. GERMINATION
•Seeds need air (oxygen), water and warmth to
germinate.
•- Seeds in boiled water covered with an oil layer
did not germinate because they lacked oxygen.
•- Water is boiled to expel air.
17. USES OF CARBON DIOXIDE
A) MAKING FOOD FOR PLANTS./PHOTOSYNTHESIS
- Green plants make their own food through a process called photosynthesis.
Photosynthesis is the process by which plants make their own food
- Sunlight, carbon dioxide, water and chlorophyll are needed during
photosynthesis.
In the process of photosynthesis, plants release oxygen into the air
B) PRESERVING SOFT DRINKS
- It is added as a preservative during the manufacturing of soft drinks e.g. sodas
Carbon dioxide is used to preserve soft drinks and prevent them from going bad
18. MAKING FIRE EXTINGUISHERS
•Carbon dioxide and water are filled in a metallic
can and used as a fire extinguisher.
•- Carbon dioxide does not support burning.
•When sprayed on a fire, it puts out the fire
19. USES OF NITROGEN
1. IN MAKING FERTILIZERS
Nitrogen is used for making fertilizers. Fertilizers are applied to plants to make
them grow well
2. IN FOOD PRESERVATION
Nitrogen is filled in food storage containers and bags to prevent the food from
going bad
20. USES OF NITROGEN
3. IN BULBS
Nitrogen is used for fill inside electric bulbs
It prevents the filament in the bulb from burning
4. IN PLANTS
- Leguminous plants fix atmospheric nitrogen into the soil nitrogen using
bacteria found in their root nodules.
- They use fixed nitrogen to make proteins.
- Legumes are sources of proteins e.g. peas, beans, groundnuts, Lucerne,
desmodium
21. USES OF NOBLE GASES
1. IN ADVERTISING LIGHTS
Noble gases are filled in fluorescent bulbs to make them glow
2. IN BALLOONS
Some noble gases such as helium is filled in weather ballons and
decorative because it is light
3. IN WELDING
Noble gases such as argon are used to melt metals in welding
22. SAFETY WHILE WORKING WITH HEAT
1. Never play with matches as this might Cause a fire
2. After you light a match, put it out before disposing of it
properly
3. Always put out the fire after carrying out any activity involving
fire
4. Do not touch hot apparatus with bare hands to avoid getting
burns. Always use gloves
24. ACTIVITY
•Explore the school and neighborhood to
identify air pollutants ie:
•smoke from cars, factories, and fires.
•Carbon Monoxide
25. EFFECTS OF AIR POLLUTION TO THE ENVIRONMENT
Harm to Plants:
• Air pollution can make it difficult for plants to grow healthy and strong.
• It can damage leaves, making it hard for plants to make food through photosynthesis.
• Some pollutants can even change the soil, making it harder for plants to get the nutrients
they need.
Trouble for Animals:
• Air pollution can make it hard for animals to breathe, just like it can for humans.
• Some animals might get sick from breathing in polluted air, which can affect their ability
to find food and survive.
• Pollution in the air can also get into the water, making it hard for fish and other aquatic
animals to live.
26. • Habitat Damage:
• Pollution can harm the places where animals and plants live, called
habitats.
• It can make habitats less safe or even destroy them completely.
• This means animals might not have a place to live or food to eat,
which can lead to fewer animals in an area.
• Changes in Weather:
• Air pollution can make the weather change in different ways.
• It can make the air warmer or colder, which affects how much rain or
snow falls.
• These changes can be bad for plants, animals, and even people who
live in affected areas.
27. •Damage to Water:
•Pollution in the air can fall to the ground and get into
rivers, lakes, and oceans.
•This can make the water dirty and unsafe for animals and
people to drink or swim in.
•It can also harm plants and animals that live in or near the
water.
28. EXTENDED ACTIVITY
•Use digital devices to observe the effects of air
pollution.
•Note: observe safety precautions in air polluted
environments (Example: practice use of dust masks,
goggles, overcoats).
•Make posters on common air pollutants, dangers of
air pollution and ways of controlling air pollution.
29. ASSESSMENT
•Identify the changes of state when
substances are heated or cooled
•Identify the components of air
•Explain the effects of air pollution to
the environment
