all science lessons term 2 for grade 7 2023-2024

What gives each state of matter its unique characteristics?

All matter is made up of particles.

What are the properties of a solid?

A solid has a definite volume and shape.

What is true about liquids?

A liquid has a definite volume but no definite shape; it can flow and take the shape of its container.

What is the characteristic of gases?

Gases have neither a definite shape nor a definite volume and are easily compressible.

What happens to particle speed when energy is added to neon gas?

The speed of the particles increases.

What does kinetic energy refer to?

Kinetic energy means the energy that a body possesses due to its movement.

What is a thermometer used for?

Thermometers measure the average kinetic energy or speed of particles in a substance.

What is the Celsius scale?

The Celsius scale is the most widely used temperature scale in the world.

What temperature is known as absolute zero?

The temperature at which particles would have no movement is recorded at 0 K.

What is potential energy?

Potential energy is the energy stored due to interactions between particles or objects.

What occurs as particles move closer together?

The forces of attraction between particles increase.

What can happen to water molecules in the presence of heat?

Hot water contains more thermal energy than cold water, even if they have the same temperature.

How is matter made up?

All matter is made up of particles called atoms.

What differentiates elements from compounds?

An element consists of only one type of atom, while a compound is made up of atoms from two or more different elements.

What is atomic mass?

Each atom has a characteristic mass referred to as the atomic mass unit (amu).

What is the law of conservation of mass?

The total mass of matter before a reaction is equal to the total mass after the reaction.

What type of reactions occur during chemical changes?

Chemical reactions can include changes in energy, color, and form.

What is the chemical formula for water?

H₂O represents that water is made of two hydrogen atoms and one oxygen atom.

What occurs during the freezing process?

Freezing is the change of state from liquid to solid, requiring removal of thermal energy.

What is the relationship between temperature and pressure in gases?

According to Boyle's Law, if temperature is constant, gas pressure increases as volume decreases.

What is the effect of adding more gas particles into a container?

Increasing the number of particles raises the pressure within the same volume.

What are renewable resources?

Renewable resources are resources that can be replaced by natural processes in a relatively short period.

What is the difference between renewable and non-renewable resources?

Renewable resources can be replaced naturally, while non-renewable resources are consumed faster than they can be replaced.

What is porosity?

The amount of pore space in a material.

How can groundwater be extracted?

Groundwater is brought to the surface through wells, typically drilled into aquifers.

What are synthetic materials derived from?

Synthetic materials come from natural resources that have undergone chemical reactions.