Primary 5 Science

The system of windpipe, bronchi and lungs that brings oxygen in and sends carbon dioxide out.

The tube joining the throat to the lungs; rings of cartilage keep it open for air.

The two tubes branching from the windpipe, carrying air into the left and right lungs.

Spongy breathing organs where oxygen and carbon dioxide are exchanged with the blood.

The system of mouth, stomach and intestines that turns food into nutrients.

A muscular bag that grinds food into a paste and mixes it with gastric juice.

The long, coiled tube where most nutrients are absorbed into the blood.

The tube that absorbs water from leftover waste and forms faeces.

A gas making up about one fifth of air, needed to release energy in the body.

Tiny useful parts of digested food that the body uses to grow and move.

The stage between childhood and adulthood when body and mind change clearly.

The first stage of life, when a baby depends entirely on adults.

The stage after infancy, when children learn to walk, talk, study and play.

The stage when the body is fully grown and one can work and care for family.

The last stage of life; strength slowly fades but experience is richest.

A chemical made by the body that acts like a signal directing growth.

The passing of features from parents to children, such as looks and height.

Changes in thoughts and feelings, such as mood swings in puberty.

The fact that everyone develops at a different time and speed — all normal.

How we see our own looks and abilities; accepting ourselves is a healthy self-image.

Harmful substances entering air, water or land, damaging the environment and health.

Measuring and recording regularly over time to track changes in the environment.

An index showing the health risk of air pollution, in bands from Low to Serious.

Tiny dust particles floating in the air; breathing too many harms the lungs.

Oxygen dissolved in water; plenty of it means good water where fish can live.

An instrument measuring how loud sounds are, used to monitor noise.

Development that meets today's needs without stealing from future generations.

The system where living things and the environment depend on each other; pollution breaks the balance.

Energy such as solar and wind power that never runs out, replacing polluting fuels.

Sorting waste paper and bottles so they can be made into new things.

The gas making up about 78% of air, its main ingredient.

The gas making up about 21% of air, used for breathing and burning.

How much a part is of the whole, such as oxygen being about 21% of air.

Air fills the space inside containers, keeping water out of an upside-down cup.

The push of the air all around us; it presses a drink up a straw.

A slender tube that, with atmospheric pressure, lifts drinks to our mouth.

A hook that grips smooth walls by atmospheric pressure after the air is squeezed out.

Heated air that becomes lighter and rises, lifting hot-air balloons.

Air flowing from place to place as warm air rises and cool air fills in.

Moving air that can turn wind turbines and carry seeds.

The slow chemical reaction of iron with air and water that turns it to rust.

The reddish-brown, brittle substance formed when iron rusts.

An experiment changing only one condition at a time so results can be compared fairly.

A protective layer painted on iron to shut out air and water.

Covering iron with zinc or chrome to shield it from air and water.

Steel mixed with special metals so it hardly rusts, used for cutlery and kitchens.

A change that can go backwards, such as water freezing and melting again.

A change that cannot be undone, such as paper burning or iron rusting.

Water turning into vapour when heated.

Vapour turning back into droplets when cooled, like drops on a cold drink bottle.

The power to make things move and work; it exists in different forms.

The energy of motion; the faster something moves, the more it has.

Energy stored because of high position or changed shape.

Energy stored in food, fuel and batteries.

Energy changing from one form to another, such as potential to kinetic.

The energy carried by electric current, turning into light, heat and motion.

The light and heat energy from the sun, a great source of energy on Earth.

Turning the energy of water, wind or fuel into electrical energy.

The rapid back-and-forth movement of an object — the source of sound.

The vibrating object that makes a sound, such as a drum skin or vocal cords.

The substance sound travels through — solid, liquid or gas.

The thin membrane at the end of the ear canal that picks up sound vibrations.

How high or low a sound is, set by vibration speed — faster means higher.

How loud a sound is, measured in decibels.

The unit of loudness: a library is about 40 decibels, a concert over 100.

Harsh, annoying sound that disturbs life, such as construction noise.

Small plugs worn in the ears to block noise and protect hearing.

Ways to guard hearing, such as lowering volume, avoiding noise and wearing earplugs.

The shape of the Earth's surface, such as mountains, plains and valleys.

A chain of connected high mountains, such as the Himalayas.

Broad, low, flat land, good for farming and cities.

The strip of low land along a river, carved by flowing water.

Broad, high land with a fairly flat top.

Land high all round and low in the middle, like a great bowl.

The shifting and squeezing of crustal plates, raising mountains or forming basins.

The slow breaking up of rock by heat, cold and water.

The wearing away and carrying off of rock by water and wind.

Sand and mud being dropped and piled up downstream or in low places.

The remains or traces of ancient life kept in rock or ice.

Creatures that lived long ago, most of them now extinct.

The body parts left after death, such as bones and shells.

Rock formed from layers of packed sediment — the common home of fossils.

The layers of rock; the deeper the layer, the older it is.

Thick ice that can keep ancient remains, such as mammoths.

An ancient sea creature whose spiral shell often becomes a fossil.

A giant ancient relative of elephants, found whole in frozen ground.

Drawing a sensible conclusion from evidence, such as reading sea fossils as signs of an ancient ocean.

A scientist who studies fossils and ancient life.

The atmosphere's state over a short time, such as rain or wind today.

The average weather of a place over many years.

How hot or cold the air is, measured with a thermometer in degrees Celsius.

The direction wind comes from, such as an east wind from the east.

How much water vapour the air holds, as a percentage; 100% means saturated.

The depth of rain fallen over a period, measured in millimetres.

The instrument that measures how much rain has fallen.

Tiny droplets hanging in air near the ground that lower visibility.

White ice crystals forming on surfaces when temperatures fall very low.

Little ice pellets formed in storm clouds before falling.

The system of the sun and the eight planets, moons and more circling it.

A giant body shining with its own light and heat; the sun is our nearest star.

A body circling a star that shines no light of its own, such as Earth.

The Solar System's eight: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune.

Earth's satellite, bright only by reflecting sunlight.

Light bouncing off a surface; the moon shines by reflecting sunlight.

The giant galaxy containing our Solar System, with hundreds of billions of stars.

All galaxies, bodies and space together — boundlessly vast.

The energy carried by light, streamed to us by the sun.

Energy that raises temperature; the sun's keeps Earth warm.

A person who studies nature through scientific research.

Finding something that already existed but was unknown.

Creating a new tool or method that did not exist before.

The malaria medicine Tu Youyou's team extracted from sweet wormwood.

A mosquito-borne disease causing chills and fevers.

Glass fibres as thin as hair that carry information at the speed of light.

A top international prize honouring scientists of great contribution.

Technology using computers and networks to handle and send information.

The quality of never giving up despite failures.

What one gives and achieves for others and society.

Technology letting computers imitate human learning and judgement, or AI.

Data so vast that only computers can analyse it to find patterns.

Technology connecting objects to the internet so they can communicate, or IoT.

A home whose lights, locks and appliances join the network for phone control.

Paying by Octopus card, phone apps and other electronic means.

Smart software that hears voice commands and answers questions.

The right to keep personal information and life to oneself.

Information identifying you, such as name, address and photos.

The secret string guarding accounts — long, complex and private.

Measures keeping computer systems and data safe from theft or damage.

The engineer's steps: define the problem, design, build, test, improve.

A person who uses science and maths to design products and solve problems.

The first model of a product, built to test whether the design works.

Material that blocks or absorbs sound, such as sponge and foam.

Measuring whether the prototype meets the targets, such as weight and noise reduction.

The unit of loudness; cutting 20 decibels means the sound drops by 20.

The requirements a design must meet, such as limits on weight and cost.

The ceiling of money available — HK$50 in this earmuff project.

Revising the design from test results so the product better meets the targets.

A scale showing weight in numbers, used to check the 200-gram limit.