Chapter 7: Heat

Chapter 6: Sources of Energy

The sun as the primary source of Energy

-Sun is the primary source of energy for earth
-Generates a large amount of energy through nuclear fusion – hydrogen atoms combines to form helium atoms- releasing a large amoun of heat and light energy
-Earth receives the het energy and light energy from the Sun
-Life on earth depends on energy from the sun
-Energy in the wind, waves and rain comes indirectly from sun- wind due to the suns heat energy causing the air to move
-Among the energy from the sun includes

• Energy in the wind, waves and rain


• Energy in fossil fuels ( natural gas, petroleum, coal)


• Energy in plants, animals and human beings


• Energy for operating appliances (solar calculators, solar cookers)

The principle of Energy Conservation

• Energy cannot be created or destroyed
• Energy can be changed from one form to another – with condition that the total energy before and after remains the same – Energy is conserved
• During the energy change, some energy may be wasted (usually in the form of heat ) but never destroyed

Click the below link to watch the video on Energy
Energy

Renewable and Non-renewable energy sources
Renewable sources – Energy sources that are always available (energy source that cannot be used up)

Non-renewable sources – Energy sources which will be used up one day

The link below is the video on Renewable and Non-Renewable Resources
Renewable Vs Non-Renewable Resources

Chapter 5: The Air Around Us

The Composition of Air

Earth has a layer of Air
– atmosphere – protects living things on earth from harmful rays

Air – colourless, tasteless and odourless – mixture of many components
Nitrogen (78%)
-Inactive gas
-Does not burn – does not allow things to burn in it
-Dilutes the oxygen in the air so that processes such as respiration, burning and decay slows down

Oxygen (21%)
-Used during respiration, burning, decay and rusting
-Required for living things to survive
-Set free during photosynthesis
-Respiration - Process of oxidising (burning) digested food in the cells of the body to produce energy, carbon dioxide and water
Glucose + Oxygen = Energy + Carbon Dioxide + Water

-Combustion – Chemical reaction that takes place when a substance combines with oxygen and produces an oxide, heat ebergy or light energy

Rare gases (0.9%)

-Helium, neon, argon – inactive but have their own purposes

Carbon Dioxide (0.03%)
-Released during respiration, burning and decay
-Used for photosynthesis

Water vapour and microorganisms
-Bacteria, fungi, dust

Air Pollution

• The addition of unwanted substances to the air (pollutant) causes air pollution
• Main pollutants – Dust, smoke, Carbon dioxide, Carbon monoxide, sulphur oxide, nitrogen oxide
• Harmful effects of air pollution
- Health problems
-Depletion of food resources
- Destructio of habitat
-Extinction of species
-Destruction of property
-Global warming
-Thinning of ozone layer

Click on the below link for videos on Air Pollution
Air Pollution

Chapter 4: The Variety of Resources on Earth

Earths resources – includes water, air, soil, minerals, fossil fuels and licing things

Water

- most living organisms are dependent to water
- also an habitat for plants and animals
- In humans- it’s the main component in blood
- to dissolve waste product and transport them out of the body
- required to digest food and transport food out of the body
- In plants - seeds cannot germinate without water
- Imagine what will happen to the roses in your garden if you don’t water them?

Air

- Earth is surrounded by a layer of air- Atmosphere- protects us from harmful radiation
- required for respiration, combustion, decay and photosynthesis
- Respiration
- Process of oxidizing food in the cells of the body to get energy- carbon dioxide and
waste product removed
- Combustion -The burning of material using oxygen to produce carbon dioxide and energy in the form of heat and light
- Decay -bacteria and fungi would break up substances into smaller part by utilizing oxygen
- Photosynthesis -Green plants makes their own food using the energy from the sun -Plants uses carbon dioxide and water in the air and in return releases oxygen

Soil

- First layer of particles on the surface of the Earth
- Habitat for plants and animals (eg: worms, microorganisms)
- contains spaces which are filled with air- facilitate the living for plants and animals
- Rich with minerals- potassium, calcium, magnesium
- Rich in humus- decaying parts of plants and animals- Food source for living organisms
- stores important fuels such as coal, natural gas and petroleum – used in industries

Minerals
- Mineral Ores- used to produce metals
-Haematite (Iron Oxide) - produces Iron
-Galena (lead Sulphide) – produces Lead

Fossil Fuels
- Coal, natural gas and petroleum
- Formed from plants and animals that are buried in the earth
- Coal – Carbon that has hardened due to pressure in the earth
- Natural Gas – used to produce raw material – hydrogen, urea, alcohol and ammonia
- Petroleum – supplies nearly half energy that are needed in the world

Plants and Animals
- Humans cannot survive without plants and animals
- Plants – souces for food, clothes, bulding material and fuel

Click the below link to view the vidoe on Natural Resources

Natural Resources

Elements, Compunds and Mixtures

Atom – smallest particle in a matter
Molecule – Made up of two or more atoms
Elements - Substance made up of one type of atom only- simplest substance
- Cannot be broken downby common chemical reactions
- Example- Copper, Carbon, Iron
- Can be grouped into metal and non-metal

Metal and non-metal
Watch the below video which explains the difference between the metal and non metal
Metal Vs Non-Metal

Compounds
– consist of two or more elements that are chemically bound together
- Example- Water (hydrogen and oxygen)
- What other examples can you think of ??????
- can be separated using chemical methods (electrolysis) or by using strong heat
- cannot be separated using physical methods

Mixtures
- substances made up of two or more types of particles that are combined physically
- not chemically bonded
- can be separated using physical methods – evaporation, filtration, magnet

Preservation and Conservation of earth resources

Air – contains oxygen and needed for respiration
Water – neede for drinking, cooking, washing, bathing
Fossil fuels – generate electricity, run machines, vehicles
Minerals – plant growth
Living things – food, clothing, oxygen
Soil – habitat, plant support, farming

Preservation – maintaining the earth resources
Conservation – sustainable use and management of resources – use wisely and do not waste

Chapter 3: Matter

Matter
- Anything that has mass and occupies space
- includes all living and non living matter
- How do you check the mass of air?
-Set two ballons each filled with air and prick one ballon- The ballon without the air becomes lighter

How to you know if air occupies space

- When you pump air into the ballon- the ballon becomes bigger because air is entering

To check more on Matter, try watching the video below

Matter

3 states of matter- solids, liquid and gas

Video to watch
State of Matter


Density- Mass per unit volume of substance

- measured in grams per cubic centimeter/ kilograms per cubic centimeter
- Objects are able to float due to their density
- If the object is less dense that the liquid- it will float
- If the object is more denser than the liquid- it will sink

Application
- Collecting hydrogen gas- hydrogen gas can be collected by bubbling the gas through the water. Since hydrogen gas is insoluble in water and less dense it will be formed on top of the water.
- Rafts
- Floats and buoys

Video on density
Density

Chapter 2: Cell As A Unit of Life

Function of Structures in cell

We need to know the function of certain structure in both animal and plant cell for this topic.
This includes the below

Nucleus- Function to control all cell activity & contains gene the decides the inherited characters

Cytoplasm- Stores water and nutrients required for cell activity and chemical processes

Cell membrane- Protects the cell and serve as the barrier for movement of substances in and out of the cell

Cell Wall- functions to protect and mantain the shape of the cell

Chloroplast- contains pigment called chlorophyll which is required for photosynthesis.

Vacuole- holds cell sap in plants and waste substances in some lower animals.

In this Chapter, You need to know how to label the animal cell and plant cell.

Plant Cell

(They have chloroplast, vacoule, cell wall, fixed shape and they store their food in starch granules)

Animal Cell

(No Chloroplast, No Cell wall, No vacoule and some lower animals do have small vocuole, no fixed shape and storage of energy via glycogen granules)

To further understand the difference between Plant and Animal Cell- Please click on the below link

Difference between Plant and animal cell

Unicellular and multicellular Organisms

Organism- A living thing (plant or animal)

Microorganism- A living thing that cannot be seen by visible eyes- only under microscope
-eg: bacteria, viruses, algae, yeast, amoeba

Unicellular organism- Organism that has only one type of cell
- Usually found in water (ponds, lakes) or moist area- active and moving
- How they carry out life processes? – by moving, feeding and respiring

Multicellular organisms- Organisms that consist of many cells (plants and animals)

To watch video related to this please click on the below link

Unicellular and multicellular Organisms

Organisation of Cells in the Human Body

Cells-->Tissu-->Organs-->System

Cells - microscopic and can only be seen under the microscope
- examples- mucle cells, epithelial cells, red blood cells, white blood cells, nerve cells

Tissues- A group of cells performing the same function

Organs - Made up of a group of different tissues which carries out a specific function
- eg- leg (bone tissues, muscle tissues, blood tissues, skin tissues, nerve tissues)

System - Consist of a group of organs working together to carry out the same function

Lets watch a video that desribes the 11 systems found in our body. Please click on the below link

Organisation of Cells in the Human Body

Form 1- Chapter 1: Introduction to Science

What is Science?

Science is the study of natural phenomena

Why do we need to study Science

It helps us to solve problems

It makes things quick

Make work Easy

Enjoy Leisure

Communication

Good Health

(There are many advantages of Science and we all depend on science to some extent in our daily life)

Science Method of Investigation

Identify the problem--> Suggesting a hypothesis--> Identifying the variable--> Carrying out the experiment--> Collecting data--> Analysing data--> Forming conclusion (Accept/Reject the hypothesis)

Physical Quantities and SI Units.

There are 5 important Physical quantities

Length (m)

Mass (Kg)

Time (s)

Temperature (Kelvin)

Electrical Current (Ampere)

Click here for Notes( Introduction to Science)

PMR Format

The PMR Paper for Science, consist of two papers

Paper 1 - Multiple Choice Questions (A,B,C,D)- 40 questions
- Time: 1 Hour

Paper 2 - Part A- 6 Questions (40 marks)- Structured Questions
- Part B- 2 Questions - Experiment based (20 marks)

This paper will test the knowledge of Science from Form 1 up to Form 3