Icas Year 7 Science

What is the difference between a physical and chemical change?

A physical change alters the form or appearance of a substance without creating a new substance, whereas a chemical change produces one or more new substances with different properties.

What are the three states of matter and how do they differ?

Solids have a fixed shape and volume, liquids have a fixed volume but take the shape of their container, and gases have neither a fixed shape nor fixed volume and can be compressed.

What is the function of mitochondria in a cell?

Mitochondria generate chemical energy in the form of ATP through cellular respiration, supplying energy for the cell’s activities.

What part of the flower produces pollen?

The anther, which is part of the stamen, produces and releases pollen necessary for plant fertilisation.

What is friction?

Friction is a force that resists the sliding motion of two surfaces in contact, converting kinetic energy into thermal energy.

What causes the seasons on Earth?

The seasons occur because Earth’s axis is tilted relative to its orbital plane, causing different hemispheres to receive varying amounts of sunlight throughout the year.

What is the role of the dependent variable in a fair test?

The dependent variable is the condition that is measured or observed in an experiment to determine the effect of changes in the independent variable.

What is the difference between conduction, convection, and radiation?

Conduction transfers heat through direct contact between molecules in solids, convection moves heat through the bulk movement of fluids, and radiation transfers energy through electromagnetic waves without requiring a medium.

What separation method removes salt from saltwater?

Evaporation removes salt from saltwater by heating the solution until the water vaporises and the dissolved salt is left behind.

What is the function of the nucleus in a cell?

The nucleus controls the cell’s functions by regulating gene expression and stores the cell’s DNA.

How can you separate sand from saltwater?

You can filter the mixture to remove sand as a solid residue and then evaporate the filtrate to recover the dissolved salt.

What is gravity?

Gravity is a universal force that attracts two masses toward each other, giving weight to objects on Earth.

What is an example of a chemical change?

Rusting iron is a chemical change because iron reacts with oxygen to form a new substance called iron oxide.

What does “compressible” mean when describing gases?

Describing a gas as compressible means its particles can be forced closer together, allowing the gas volume to decrease under pressure.In other words, compressible gases can change their volume significantly when subjected to external forces.

How does light travel?

Light travels in straight lines as electromagnetic waves and can change direction when it reflects off surfaces or refracts through different media.

What is a controlled variable in an experiment?

A controlled variable is any condition that is kept constant throughout an experiment to ensure that only the independent variable affects the outcome.

What happens during photosynthesis?

During photosynthesis, plants convert carbon dioxide and water into glucose and oxygen using energy from sunlight in their chloroplasts.

What is buoyancy?

Buoyancy is the upward force exerted by a fluid that opposes the weight of an immersed object, enabling it to float or partially submerge.

What causes tides on Earth?

Tides are caused primarily by the gravitational pull of the Moon and, to a lesser extent, the Sun on Earth’s oceans.

What tool is used to measure temperature?

A thermometer measures temperature by indicating the thermal expansion or contraction of a substance, often calibrated in degrees Celsius or Fahrenheit.

What makes an experiment a fair test?

An experiment is fair when only the independent variable is changed, the dependent variable is measured, and all other variables are controlled.

What is mass and how is it different from weight?

Mass is the amount of matter in an object measured in kilograms, whereas weight is the force of gravity acting on that mass measured in newtons.

What is a habitat?

A habitat is the natural environment in which an organism lives and obtains the resources it needs to survive and reproduce.

Why do gases fill their container?

Gases fill their container because their particles move randomly and spread out to occupy all available space.

What are renewable energy sources?

Renewable energy sources are natural resources such as solar, wind, and hydro that are replenished faster than they are consumed.

Earth’s Crust

The solid outer layer of the Earth where we live; broken into tectonic plates.

Mantle

The layer beneath the crust made of hot, semi‑solid rock that flows slowly.

Outer Core

The liquid, metal layer beneath the mantle; generates Earth’s magnetic field.

Inner Core

The solid, dense centre of the Earth composed mostly of iron and nickel.

Tectonic Plate

A large slab of Earth’s crust that floats on the mantle and slowly moves.

Convergent Boundary

Where two plates move toward each other, causing mountains or volcanoes.

Divergent Boundary

Where two plates move apart, allowing magma to rise and form new crust.

Transform Boundary

Where two plates slide past each other, generating earthquakes.

Convection Currents

Movement of molten rock in the mantle (hot rises, cool sinks) that drives plate motion.

Mid‑Atlantic Ridge

Example of a divergent boundary running down the centre of the Atlantic Ocean.

Dichotomous Key

A step-by-step identification tool that offers two choices at each branch.

1a / 1b Dichotomous Key

The labels for the two options in each step of the key.

Has feathers → go to 2

An example directive leading you down the feathered branch.

No fur → Crocodile

An example outcome identifying a reptile without fur.

Purpose of Dichotomous Key

Creates clear yes/no decisions for accurate organism identification.

Mixture

A combination of two or more substances not chemically bonded.

Filtration

Separates insoluble solids from liquids using filter paper.

Evaporation

Recovers dissolved solids by heating until the liquid turns to vapor.

Distillation

Separates liquids by vaporizing and re‑condensing based on boiling points.

Magnetic Separation

Uses a magnet to remove magnetic materials (iron, nickel) from a mixture.