Scientists use models to explain phenomena because:

• Models are more fun to create

• Phenomena are often too complex to observe directly

• Models are easier to publish

• Phenomena are not important

The Particle Model of Matter states:

• All matter is made up of large particles

• Only living matter is made of particles

• All matter is made up of tiny particles, with each pure substance having its own kind

• Particles do not vary between substances

According to the Particle Model of Matter, particles:

• Are always at rest

• Are constantly in motion, have spaces between them, and attract each other

• Only move when heated

• Never attract each other

In which state of matter are particles most tightly packed?

• Solid

• Liquid

• Gas

• Plasma

During the process of melting, particles:

• Move closer together

• Gain energy and move apart

• Lose energy and move closer

• Stop moving completely

When conducting a scientific investigation, which step involves gathering numerical data?

• Aim or problem

• Method or procedures

• Results including data

• Results including data

Which part of a scientific investigation involves stating what the researcher aims to discover?

• Materials and equipment

• Method or procedures

• Aim or problem

• Results including data

Which of the following diagram represents LIQUID?

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In a solution, the solute is:

• The substance that does the dissolving

• The substance being dissolved

• Always a solid

• Always a liquid

Which substance is likely to react with litmus paper to show an acidic reaction?

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