F1 Chapter 7

Railway tracks

If a continuous railway track is used for railway lines, the track will buckle when temperature rises. This will cause a train to derail. To prevent this, small gaps are left between sections of the iron rails. These allow the tracks to expand in hot weather.

Electricity cables and telephone wires

On a hot day, electricity cables and telephone wires expand and sag. In the early morning or at night, the temperatures are low. Cables and wires contract and tighten. Electric cables and telephone wires are hung loosely to allow for expansion and contraction.

Metal bridges

Usually, one end of a bridge is fixed. The opposite end rests on rollers. There is also a sliding joint at the moving end. When the metal bridge expands or contracts, it is not damaged.

Concrete road surface

If concrete road surfaces and pavements were laid down in one continuous piece, cracks would appear. Road surfaces and pavements expand and contract because of changes in temperature. To prevent cracks, small sections or tiles are used. The gaps between these sections are filled with a soft material. On a hot day, the tiles expands and squeeze the material so that the concrete road surfaces and pavements will not crack easily.

F1 Chapter 6

F1 Chapter 5

Pollutants in the air 

Air pollution occurs when air contains pollutants. Pollutants are substances that are released into the environment. These substances are harmful to living things and pollute the environment. Air pollution is the result of human action.

 Sources and effects of air pollutants on human beings and the environment

Air pollutants	Sources	Effects
Smoke, soot, haze	- Burning of waste - Burning of fuels by factories, power-generating stations and vehicles - Forest fires - Cigarette smoke - Smoke from vehicle exhausts	- Pollute the environment and make buildings dirty - Slow down the process of photosynthesis in plants - Damage the respiratory system - Cause respiratory problems - Damage the liver and cause cancer
Dust	- Quarries - Cement - Timber - Asbestos factories - Exposed riverbeds or shoreline	- Pollutes the environment - Make buildings dirty - Damage the lungs - May cause lung cancer - Reduce the productivity of farmlands

Carbon dioxide	- Burning of rubbish - Burning of fuels - Volcanic out-gassing - Wildfires - Respiration process of living aerobic organisms	- Cause the greenhouse effect - Cause global warming - Cause breathing difficulties - Rises of sea level - Increase extreme weather
Chlorofluorocarbons	- Aerosol cans - Refrigerators - Air conditioners - Electronic factories - Blowing agent	- Destroy the ozone layer in the Earth’s atmosphere - Cause cataracts - Cause skin cancer - Cause eye damage - Immune suppression
Carbon monoxide	- Burning of hydrocarbons - Exhaust gases from motor vehicles - Cigarette smoke - Gas stoves - Water heater	- Can cause dizziness - Cause headaches if inhaled in small amounts - Cause death if a large amount is inhaled - Cause brain damage - Cause the greenhouse effect

Steps to prevent and control air pollution

1. Avoid using fuels that release a lot of smoke, smog and soot. Encourage the use of liquid petroleum gas and electric equipment.

2. Legal action must be taken against owners of factories or vehicles which pollute the environment.

3. Fix catalytic converters on all motor vehicles to convert harmful exhaust gases into carbon dioxide, nitrogen and water.

4. Fix a filter on the smoke ducts of chimneys in factories to trap pollutants before smoke is release into the surrounding air.

5. Control the use of fertilizers and pesticides which are used to increase agricultural yield.

Ways to maintain the quality of air

1. Ban open burning.

2. Car pool whenever possible. This will help to reduce the number of vehicles on the road.

3. Install catalytic converters on vehicles. These convert harmful gases into less harmful substances.  

Habits to maintain the quality of air

1. Recycle papers,bottles and tins. This reduces waste and conserves natural resources.

2. Use public transport such as commuter trains, buses and the LRT.

3. Walk or cycle whenever possible.

4. Take part in tree-planting activities.

5. Use less electricity. Saving electricity means fewer pollutants will be released as the demand for electricity decreases

F1 Chapter 4

Meaning and Importance of the Preservation and Conservation of Resources on Earth

­­­­­­ Those who are concerned with protecting the environment often use the words conservation and preservation. These two terms are often confused and are used to mean the same thing although differences exist.

Preservation attempts to maintain in their present condition areas of the Earth that are so far untouched by humans. It ensures that we do not lose our natural resources to development. Examples of efforts in preservation are the setting up of forest reserves, state parks, national parks and marine parks. These efforts ensure that the flora and fauna in these protected areas would still be around for the future generations to see. 

Conservation is the sustainable use and management of Earth's resources. Conservation of natural resources usually focuses on the needs and interests of human beings. On the other hand, conservationists accept that development is necessary for a better future, but only when the changes take place in ways that are not wasteful. Conservation of resources ensures that we maintain sufficient quantities of resources for future generation to use. 

Conservation and preservation of natural resources are necessary to prevent the destruction of the environment. The planets natural ecosystems and regenerating bio-capacity are being severely degraded and causing the extinction of some species. The natural disasters are also need to prevent. They cause a great loss of life and property. Health problems will increase if we don't  colnservate and preservate the natural resources.

On the other way, we need to prevent the shortage of clean water for drinking and washing. Damage to the balance and beauty of nature will also increase if we don't prevent it. The loss of economic resources are also need to prevent. We can prevent them by reduce the usage of economic resources.

Conclusion, preservation and conservation of resources on Earth requires the cooperation of individuals, communities and governments. 





F1 Chapter 3

Describe how man uses the different states of matter

1. Gas can be compressed and stored in a gas tank.
2. Petroleum and natural gas can be transported through pipe because they can flow.
3. Liquid clay is easily shaped into flowerpots which become hard solids after heating.

Describe how man applies the concept of density

1. Transporting Log - Logs are less dense than water.They are transported by rivers to factories.
2. Buoys - Buoys are fixed to the surface of the sea to mark a place that is dangerous for ships.
3. Hot Air Balloon - When the air is heated and become hot,it will expand.The hot air is less dense than the air around the balloon.

Application of the concept of floating and sinking related to density

Submarine

 
 

F1 Chapter 2

 Human beings are Complex Organisms

1.  Allows human beings to have the ability to talk, think rationally, create new things, learn from experience and use languages.


2. Have a more complex communication than any other creature.


3. Comprised of billions of cells, each of which are made of numerous smaller parts.


4. Cells—> Tissues—> Organs—> Systems—> Organism. 


5. Various systems in the human body are well organised to carry out all the life processes efficiently.

F1 Chapter 1

The Importance of Standard Units

1.  Allow to compare quantities that are not in the same space, place or time.  

2.  Indicates the physics quantities measured or been measure as each quantities has particular units.

3.  Makes it easier for people from different countries to communicate with each other.

4.  Avoid final calculation to be inaccurate as substitute data in any formula.

5.  Have the same value anywhere in the world.