Revision notes, what you should know

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       Highlighted on light blue subtitle
       Highlighted on light green answers    

       Highlighted on yellow quetions

Classification and use of keys

B1a What do all living things do?

. Living things are called organisms.

. Organisms must do all of these things: Move, Reproduce, use their Senses,

Grow, Respire, Excrete waste and take in Nutrition.

. You can remember all seven of these using the phrase ‘MRS GREN’.

B1b How do scientists divide living things into groups?

. Dividing things into groups is called classification.

. Living things are divided into kingdoms. Members of the plant kingdom can

make their own food, animals cannot.

. Vertebrates are animals that have backbones.

B1c What are the differences between vertebrate groups?

. The main features of amphibians, birds, fish, mammals and reptiles.

. Each type of animal (or plant) is called a species.

B1d What are invertebrates?

. Invertebrates are animals without backbones.

. The main features of arthropods, echinoderms and molluscs.

What groups can arthropods be divided into?

. The arthropods are split into four smaller groups: arachnids, crustaceans,

insects, and centipedes and millipedes.

. The main features of these groups.

B1e What groups are plants divided into?

. The main features of mosses, ferns, conifers and flowering plants, and how

they reproduce.

. Plants make their own food using energy from the sun in a process called

photosynthesis.

Cells and their functions

B2a What are the differences between plant and animal cells?

. Animal cells have a nucleus, cytoplasm and a cell membrane.

. Plant cells also have a cell wall, a vacuole and chloroplasts.

. What all of these parts do.

How do we use a microscope?

. The main parts of a microscope and what they do.

B2b How can we look at cells?

. How to prepare a microscope slide.

B2c Why do cells have different shapes?

. Some cells are adapted to do special jobs.

. How ciliated epithelial cells, nerve cells and root hair cells are adapted.

. A group of the same sort of cells is called a tissue.

B2d What is an organ?

. Different tissues are grouped together to form organs.

. Each organ has a very important job.

What do human organs do?

. About all the organs on the next page, where they are and what they do.

What do plant organs do?

. About all the plant organs on this page where they are and what they do.

. Plants make their own food using photosynthesis.

. Photosynthesis needs light to work.

. Photosynthesis uses up water and carbon dioxide and makes sugar and

oxygen.

B2e How do organs work together?

. Cells group to form tissues. Tissues group to form organs. Organs group to

form organ systems. All of these make up a living thing – an organism.

. Water is lost by plants though their leaves. The organs in the breathing and

digestive systems.

Solutions and Indicators

C1a How do we know if something has dissolved?

. Some solids dissolve in water to make a solution. These solids are soluble.

. A solution contains a solute (solid) and a solvent (liquid).

. A solution is always transparent.

. Solids that do not dissolve are insoluble.

What is the difference between melting and dissolving?

. Solids can melt when they are heated. They change back when they cool

down.

. Dissolving occurs when a soluble solid mixes in with a liquid.

. Mass of solvent + mass of solute = mass of solution.

C1b How much solute can we dissolve?

. When no more solute can be dissolved in a solution, it is said to be saturated.

. The amount of solute that dissolves depends on the volume of solvent (e.g.

water) and its temperature.

How can we make things dissolve faster?

. You can make something dissolve more quickly by stirring it, by crushing it

into smaller pieces, or by heating the water.

C1c How can we remove ink or paint marks?

. Water is the most common solvent.

. Other liquids can also be used as solvents.

. Solutes which are insoluble in water may dissolve in other solvents.

C1d What is an indicator?

. Litmus is an indicator which is red in acids.

. Vinegar and fruit juices are acids.

What is an alkali?

. Litmus turns blue in alkalis.

. Alkalis can cancel out acids, making them neutral. We call this neutralisation.

. Some alkalis are dangerous.

C1e How can we make a better indicator?

. The strengths of acids and alkalis can be measured on the pH scale.

. pH numbers 1 to 6 are acids, 7 is neutral, and 8 to 14 are alkalis.

. You can find out the pH number using universal indicator.

Mixtures and separating techniques.

C2a How can we make use of everyday mixtures?

. A mixture is different materials mixed together.

. Examples of some useful things obtained from some everyday mixtures.

C2b How do we get clean water?

. Filtering can be used to separate solid particles which do not dissolve from

the liquid that is holding them.

. Filtering cannot be used to separate particles which dissolve in the liquid.

C2c Why doesn’t all water taste the same?

. Most water has small amounts of salt dissolved in it.

. If you evaporate the water the salt is left behind.

C2d How can we make pure water?

. Distillation is evaporation followed by condensation.

. What mixtures distillation can be used to separate.

C2e How can mixtures of dissolved solids be separated?

. What chromatography is, how it works and it is used for.

. How to make a chromatogram.

Particle Theory

C3a Why do different materials have different properties?

. Materials have different properties because they are made from particles

which are arranged in different ways, making a solid, liquid or gas.

. A solid can be melted into a liquid by heating it.

. A liquid can be frozen into a solid by cooling it.

. A gas can be condensed into a liquid by cooling it.

. The meanings of the words evaporating, condensation, freezing and melting.

. For any substance, the freezing point and melting point are the same.

C3b What is a solid?

. Solids are made up of particles that are very close together.

. Solids are difficult to squash, do not flow, have a fixed shape and volume, and

have a high density.

C3c Why do liquids flow?

. Liquids are made up of particles that are fairly close together.

. Liquids cannot be squashed, flow quite easily, and have a fixed volume but no

fixed shape.

. Although they are dense, liquids have a lower density than solids.

C3d How are gases different from solids and liquids?

. Gases are made up of particles that are well spread out.

. Gases are easy to squash, flow easily, have no fixed volume and no fixed

shape.

. Gases have a lower density than liquids.

C3e What is the difference between a solid, a liquid and a gas?

Changes of State

C4a What do we mean by the word ‘state’?

. The three states of matter and their properties.

. What boiling, evaporating and condensing mean.

C4b How can freezing make you hotter?

. What melting and freezing mean.

. All changes of state involve heat energy moving from one place to another.

How can freezing stop food and drinks going off?

. At room temperature, food goes off because bacteria grow and reproduce

quite quickly. This can cause food poisoning.

. Bacteria grow and reproduce more slowly at low temperatures.

C4c What happens to water when we boil it?

. When it is boiling, the temperature of the liquid stays the same.

. What bonds are and what happens to them when water is heated.

C4d What happens if we keep on diluting?

. All drinks contain water. Most also contain colourings and flavours.

. All substances are made up of tiny particles.

. What dilute and concentrated mean.

. The difference between an observation, a theory and a prediction.

C4e How do the smells of cooking spread from the kitchen?

. What diffusion is.

. Diffusion occurs because particles in a substance are always moving.

. Why diffusion is faster in gases than liquids.

Which energy sources rely on the Sun?

. The energy sources used in geothermal, tidal and nuclear power are the only

ones that do not depend on the Sun.

. The Sun is the original source of energy for most of our energy sources.

P4d How is energy wasted in energy changes?

. When energy is changed from one form to another, useless heat energy is

often produced.

P4e How can we use less of our non-renewable fuels?

. How heat loss can be reduced by using insulating materials containing

trapped air.