Secondary 1 Science

Recording what happens systematically with senses or instruments.

A testable prediction based on what is already known.

A factor that is changed, measured or kept constant in an investigation.

Data from observations or measurements used to support or challenge an explanation.

An investigation that changes only one variable while keeping all other conditions the same.

The factor deliberately changed by the investigator in an experiment.

The result that is measured as the independent variable changes.

A factor kept constant throughout the experiment to keep the test fair.

A factor that can potentially cause harm.

The chance that a hazard will actually cause harm; it can be reduced by precautions.

A pictogram showing the type of hazard a chemical poses.

Catches fire easily when near a flame or spark.

Able to attack and destroy skin, eyes and metals.

Harmful or lethal when it enters the body.

The three things a fire needs: fuel, oxygen and heat — remove one and the fire goes out.

Emergency equipment for rinsing the eyes after a chemical splash.

A graduated glass tube for measuring liquid volume.

A straight ruler for length, marked to the nearest millimetre.

A timer for measuring time intervals.

An electronic instrument for measuring mass; zero it before use.

An instrument for temperature; immerse the bulb fully in the liquid.

How close a measurement is to the true value.

How close repeated measurements are to one another.

Reading error caused by viewing the scale at an angle.

Taking in food or nutrients to obtain energy and materials for growth.

Releasing energy by breaking down nutrients — happens in every cell.

Responding to changes around them, e.g. mimosa leaves closing.

The process by which an organism increases in size and complexity over time.

The life process of producing offspring to continue the species.

Removing waste, e.g. carbon dioxide, urine.

Moving the whole body or parts of it, as animals do.

The sum of all chemical reactions inside an organism, including building up and breaking down substances.

The basic unit of life, extremely small.

An instrument that magnifies tiny objects so they can be seen.

An organism made of one cell, like an amoeba.

Made of many cells, like humans and trees.

A complete living individual, made of one cell or many.

All living things are made of cells; the cell is life's basic unit; new cells come from existing cells.

A cell adapted in shape and structure for a particular job, such as a red blood cell carrying oxygen.

A group of similar cells working together, which then builds organs.

The control centre of the cell.

Controls what enters and leaves the cell.

Jelly-like substance where reactions happen.

Plant cells only: rigid outer layer for support.

Plant cells only: where photosynthesis happens.

Stores water and substances; large in plant cells.

The powerhouse: releases energy for the cell.

The instructions stored in the nucleus that determine an organism's traits and are passed to the next generation.

A tiny unit that makes up matter and cannot be seen by the naked eye.

Has a fixed shape and volume; particles vibrate around fixed positions.

Has a fixed volume but no fixed shape; particles can slide past one another.

Has no fixed shape or volume; particles are far apart and spread in all directions.

The spreading of particles from where they are more concentrated to where they are less concentrated.

The change of state from solid to liquid on heating.

The rapid change from liquid to gas throughout the liquid when heated.

The pressure produced when gas particles constantly collide with the walls of their container.

The basic particle of an element — the smallest unit in chemical change.

A pure substance made of only one type of atom.

A pure substance in which different elements are chemically joined in fixed proportions.

Several substances mixed without forming a new chemical substance; the proportions can vary.

A particle made of two or more atoms joined together; a water molecule contains two hydrogen atoms and one oxygen atom.

A shorthand using element symbols and numbers to show what a substance contains, e.g. H₂O for water.

A change that produces new substances, such as iron rusting into iron oxide.

A substance made of only one kind of matter with a fixed composition; elements and compounds are both pure substances.

Making food from carbon dioxide and water using light energy.

The green pigment that absorbs light.

A gas taken in from the air through stomata — a raw material of photosynthesis.

A product of photosynthesis, released into the air.

The food made, used for growth or stored as starch.

The storage form of glucose; turns blue-black in the iodine test.

The structure inside plant cells where photosynthesis takes place; it contains chlorophyll.

Tiny pores on the leaf surface through which carbon dioxide enters and oxygen and water vapour escape.

Energy associated with particle motion and arrangement that can move from place to place.

Transfer through a solid as neighbouring particles pass energy by collisions.

Heat transfer by circulating movement in a fluid as warm fluid rises and cool fluid sinks.

Transfer of thermal energy by electromagnetic waves, without needing a medium.

Electromagnetic waves given out by the Sun and warm objects, carrying heat without a medium.

A material that conducts heat easily, such as metal.

A material that conducts heat poorly, such as air, plastic and wood.

Mass per unit volume; heated fluid becomes less dense and rises, which drives convection.

The spinning of an object around its own axis.

The movement of an object around another object along an orbit.

The path followed by an object moving under gravity.

The changing shape of the Moon's sunlit part as seen from Earth.

The imaginary line through Earth that it spins around, tilted by about 23.5 degrees.

When the Moon moves between the Sun and Earth and blocks the sunlight.

When the Moon moves into Earth's shadow and darkens.

The periodic rise and fall of sea level, caused mainly by the Moon's gravity.

Liquid water absorbing heat at its surface and turning into water vapour.

Water vapour cooling and changing into tiny liquid droplets.

Water falling from clouds as rain, snow, hail or similar forms.

Short-term conditions of temperature, wind, clouds and precipitation in a place.

The continuous movement of water between oceans, the atmosphere and land.

The gaseous form of water, present in the air.

A visible mass of countless tiny water droplets or ice crystals.

The long-term average pattern of weather in a place over many years.