Prevent... from

Eg. The barrier was put up to prevent people from falling over.

You can prevent the sun from shinning into the house by pulling down the curtain.

Amiable Vs Amicable

Amiable – pleasant and easy to get along

Amicable – People show friendliness towards one another and do not want to quarrel

Eg. Susan is amiable and everyone likes her.

Tricia is amicable and does not want to quarrel with the unreasonable boy.

Force

Force = Mass x Acceleration (F=ma)

Work is done only when an object is being moved.

To moved things, we can pull or push (apply force).

Forces can be seen but their effects can be seen and felt.

A force can be seen when:

v A stationary objects moves

v A moving object moves faster

v A moving object changes direction

v A moving objects stops

v The object changes its shape.

Balanced forces do not cause a change in motion.

Gravitational Force

v Is the pull of gravity

v Measured by weight

v Decrease with increasing distance from the centre of the Earth.

v The higher the object is from the ground the more gravitational potential energy.

v The larger the mass, the greater the gravitational force.

v Acts from a distance.

Frictional Force

v Produced when two things rub each other.

v Acts in the opposite direction

v The rougher the surface, the more friction it has.

v The heavier the mass, the greater the friction.

v Advantages: Prevent us from falling.

v Disadvantages: Cause wear and tear and heat – waste energy.

v Use lubricants, rollers and ball bearings to reduce friction.

Elastic Spring Force

v When an object is acted upon by a force, it can be compressed, stretched or bend.

v If the object returns to its original shape after the force is removed, it is said to be elastic.

v Found in rubber band and spring.

Take note of the graph that comes with the question.

The graph above measures the extension – so it starts from 0cm. It did not mention the length of the original spring.

The graph below measure the length of the entire spring – so it does not start from 0cm.

The heavier the mass, the longer the extension. The extension will be constant until it comes to a point where the spring cannot return to its original length.

Magnetic Force

• Magnetism is the attractive or repulsive force that acts between magnetic materials
• Can pass through non-magnetic substances
• Can act from a distance

Consist of = comprise

The ingredients of the soup consist of mushroom, cream and water.

The ingredients of the soup comprise mushroom, cream and water.

Alphabet Vs Letters

A-Z are letters of the English Alphabet.

The whole set of A-Z letters makes up the alphabet.

Cynical Vs Skeptical

Cynical person – assumes and expects the worst of others.

Eg. The cynical manager thinks that we will not be able to anything without him.

Skeptical person – hard to convince

Eg. My mother was skeptical when I told her that I was the first in class.

Prepositions

Prepositions are words that link the person or thing with the rest of the sentences. They also express time, show position or indicate direction.

Examples:

I am going to the zoo today.

There’s a butterfly on my back. Can you get it off me?

I am born in Singapore.

The ruler is made of wood.

Humpty Dumpty has fallen off the wall.

My puppy was missing since 2 weeks ago.

I waited until my parents got home before I go to bed.

We have to think out of the box.

Photosynthesis and Respiration

Only green plants can make food through the process of photosynthesis.

Photosynthesis the process whereby plants make food using water and carbon dioxide in the presence of sunlight in order to produce sugar and oxygen.

Chlorophyll in the plants interacts with sunlight to split the water present into hydrogen and oxygen.

Air is exchange through the stomata which are found mostly on the underside of the leaves.

During photosynthesis, light energy is converted into chemical energy.

Food can be stored in different plant parts:

v Roots – carrots, sweet potato

v Stems – sugarcane, potato

v Leaves – cabbage, onion

v Fruits

v Seeds – groundnuts, maize, rice

A food chain shows how energy is transferred from one type of organism to another.

As energy moves up the food chain, it gets lesser because it has been transformed into other forms of energy.

Green plants and certain types of bacterial and algae are primary producer because they produce usable energy for other living organisms.

Predators and scavengers are known as secondary consumers.

Decomposers are organisms that feed on dead plants or animals and break them down into simpler substances.

Eg. Bacteria and fungi.

Maggots, dung beetles, ants and earthworms are the helpers.

Respiration takes place in all living things – it is the process where energy is released from glucose to carry out life processes.

Breathing is the mechanical procedure in which air reaches the lungs.

Between… and

The word ‘between’ is used with ‘and’.

Eg. I am sitting between John and Sally.

The temperature is between 24 and 32 degree Celsius.

Come to my house between 1pm and 3pm.

Energy (1)

Energy is the ability to do work.

Plants convert light energy from the Sun, carbon dioxide and water into food (sugar).

All energy available on Earth comes from the Sun through the process of photosynthesis.

Solar, wind, wave energy, biomass and geothermal energy and hydropower are examples of renewable energy.

Solar cells can collect energy from the Sun to power satellites and calculators.

Solar energy can be transformed into electricity using the photovoltaic (PV) panels.

Disadvantages of using electricity that is generated by solar energy:

v The Sun’s rays are too scattered and irregular.

v It can be interrupted by the cloud cover.

v The cost of setting up the PV panel may be high.

Energy is constantly changing from one form to another.

Lose…lost…lost

‘Lost’ is the past tense and past participle of ‘lose’.

Eg. I often lose my things because I am forgetful.

I lost my pencil case yesterday.

My pencil case was lost yesterday.

Stay Vs Live

Stay – remain in a place, to live at a place for a short period of time

Live – to have your home there

There is a feel of permanence to the word ‘live’ that ‘stay does not have.

Eg. I stay at my grandmother’s place during the weekends.

I live in Woodlands with my parents.

Environment

There are many different types of environment – desert, forest, grassland, tundra and estuary.

Environment includes all the factors that affect the growth, development and survival of organisms.

Physical factors

· Amount of light

· Temperature

· Amount of water

· Type of soil

Other factors

· Availability of food

· Other organisms that compete for food

· Other organisms that cause diseases

· Presence of predators

The way all the factors in an environment interact determines which organisms can live in that environment.

Ecology is the interactions of organisms with one another and with the environment in which they occur.

The factors that affects the environment are:

· sunlight

· temperature

· Rainfall

· climate

· soil conditions

o loamy, clayey and sandy

· presence of other organisms

o disease causing, prey, predator

Changes in the environment can be natural or influenced by humans.

Plants and animals in the environment must adapt to the changes in the environment or they will extinct.

Pollution is a change in the environment that can influence health, survival or activities of organisms.

A group of organisms of the same kind is known as the population.

When different groups of organisms live together, they form a community.

A habitat is a special place where the organisms live and grow together.

An animal needs food, water, shelter and a place to raise its young. If the habitat is not suitable, it will move to a better habitat.

Animals use plants for shelter and for food, while plants depend on the animals to carry their pollen and to disperse their seeds.

Food Web

The main source of energy for life on Earth comes from the Sun.

When being eaten, the energy is passed from one organism to another.

Organisms that use the Sun for producing food are called food producers.

Organisms that get energy by eating other organisms are called food consumers.

Food consumers must eat food producers or other food consumers to obtain their energy indirectly from the Sun.

Primary consumers are animals that feed on plants (herbivores).

Secondary consumers are animals that feed on other organisms (carnivores and omnivores).

The waste and dead animals are broken into smaller pieces by detrivores ( earthworms, millipedes, ants , etc)

Decomposers, bacteria and fungi, will break the waste into simpler substances.

When the number of prey increased, the predators will also increase because there is plentiful of food.

When the number of predator, the number of prey will decrease because they are being eaten up.

The factors that can cause the population to increase are:

· Birth

· Plentiful of food – more animals move into the habitat

The factors that can cause the population to decrease are:

· Death – due to illness, and increase in the number of predators

· Lack of food – animals move to other habitat.

Adaptation – Plants

Adaptation to the hot weather:

Ø Desert plants reduce the size and number of leaves to prevent the loss of water.

Ø Some plants have long roots to reach water sources beneath the soil.

Adaptation to the light:

Ø Lianas climb over other plants so that it can receive more sunlight.

Ø Plants have dark green leaves with red underside. The red serves to reflect light back into the leaf.

Ø Grapes have tendrils that cling onto support.

Ø Morning glory has twining vines.

Ø Some plants have clasping roots to climb by tendrils with disk-like adhesive tips that attach themselves to any surface.

Adaptation to getting more water:

Ø Cacti store water in their stems. They keep their stomata closed during the day to prevent loss of water.

Ø Deciduous plants shed their leaves to prevent the loss of water.

Ø Some plants slow growth to help use less water, food and energy during the hot season.

Ø Some plants have long roots so that they can obtain water from deep under the ground.

Aquatic plants’ adaptation:

Ø All floating plants have either air spaces trapped in its roots or large air spaces to help it float to obtain sunlight.

Ø They have air on its leaves to trap air.

Ø Water hyacinth has swollen stem at the base of its leaves to help it float.

Ø Duckweed leaves are small and the tiny roots dangle below the water surface.

Ø Water lily (partially-submerged plant) have large floating leaves. The flat round leaves have a waxy water repellent upper side and are able to float on water.

Adaptation - Animals

An adaptation is a way an organism’s body helps it survives or live in its environment.

Having the ability of adapt to changes in the environment is important for an organism’s survival.

Adaptations in animals help them to:

Ø Obtain food

Ø Keep safe

Ø Build homes

Ø Withstand weather

Ø Attract mates

Physical adaptations help animals to get food and water or protect themselves.

Ø Birds have different types of beaks meant for the different type of food they consume.

Ø Birds have different types of feet to suit their movement and way to get their food.

Animals adapt certain behaviours or actions to increase its chances of survival.

• Having a special appearance, camouflaging


• Moving in groups

Adaptation to the cold weather:

Ø Polar bears have thick hair to protect them from the cold.

Ø Some birds migrate to warmer places during the colder months.

Ø Bears hibernate during the colder months.

Ø Beavers and squirrels store food prior to the winter months so that they have constant supply of food.

Ø Squirrels and mice hurdle together to keep warm.

Adaptation to the hot weather:

Ø Having light colouration to reflect light, so that the animals do not take in too much heat.

Ø Desert animals reduce water loss by avoiding the heat and are active in the night

Ø Owls and nighthawks gape open-mouthed to dissipate the heat.

Ø Jackrabbit have long ears to release heat.

Ø Some animals are able to retain water in their body for long period of time.

Adaptation to the light:

• Use of echolocation by bats.
• Owls have the ability to rotate their neck 270 degree to aid their vision.

Adaptation to movement in water:

• Fish have fins to help them balance and move in water.
• Fish have streamlined body to help it move faster because it can cut through the water more efficiently than other shapes.
• Amphibians have webbed feet to help push against the water.
  
  
• Crocodiles and polar bears close their nostrils when swimming in the water.

• Dolphins and sea turtle have flippers that acts like paddles to help steer through the water.

• Water birds have special oil which does not allow water to penetrate their feathers.

Adaptation to breathing in water:

• Whales and dolphins have blowholes to breathe out air.
• Fish have gills to breathe in the water.
• Water scorpion and the wriggler have breathing tubes.
• Diving beetle and water spider trap air in bubbles in order to breathe in water.

Adaptation to getting more water:

Ø Desert tortoise store water under their shell.

Ø Gila monster and camels store fats in so that they can live off this fat when there is not enough water.

Ø Most animals conserve water by keeping cool and are active in the morning, evening and after dark.

Adaptation for obtaining food and feeding:

Ø Most predators have sharp teeth, claws and jaws that they use to eat meat.

Ø Plant eating animals have small, pointy teeth or chopping or large flat teeth for crushing and grinding.

Ø Hummingbird has small, long and hallow beak to probe into flowers.

Ø Hawk has curved beak with sharp point to rip the flesh of its prey.

Ø Toucan has long, thick beak that helps to pluck the fruit on trees.

Ø Some animals will ambush their prey and make surprise attack.

Eg. Sparrowhawk.

Ø Lions, killer whales live and hunt in family teams so that they can protect their young at the same time.

Ø Some species of spider inject venom into their insect preys, paralyzing them and dissolving them from within.

Ø Animals have sharp sense of vision. Hearing and smell that helps them to hunt for food.

Adaptation for escaping predators:

Ø Rhinoceros have horns to fight off predators.

Ø Some animals are active only at night so that it is harder for the predator to find them.

Ø Some butterflies appear to look like other organism so that the predators thought them to be poisonous or bad-tasting and thus leave them alone (mimicry)

Ø Some butterflies have eyespots on their wings to fool the predators to think that they are other animals.

Ø Bumblebee and the yellow wasps have bright warning colours to tell the predators to stay away.

Ø Some animals give unpleasant taste or poison when the predators eat them.

Ø The ostrich has long legs to flee, the mice have holes that the predators cannot enter and the octopus give off black ink clouds so that they can escape.

Camouflage is the use of colours to match the place where the animals live so that they cannot be spotted easily.

This method can be used by the predator so that they are not easily spotted by the prey when they approached.

Some preys also use this method so that the predator cannot see them easily.