Year 8 Science 

Summer Exam 

Revision List

Revision Notes - Separating Techniques

Substances that are mixed together can be easily separated a number of separating techniques based on the properties of the substances: 

Solutes, Solvents and Solutions

One property of salt is that it is dissolves in water – it is Soluble.

It is said to be a Solute. Other solutes include sugar or a bath bomb as they also dissolve into water and form a Solution.

Any liquid that allows substances to dissolve into it at called solvents.

Nail varnish is a solvent as nail varnish dissolves into the nail varnish remover to remove it off the nail.





Solvent + Solute = Solution

Revision Notes - Separating by Filtration

Used to separate an insoluble solid from a liquid. Eg Sand from Water. The residue (sand) is collected by the filter paper and the filtrate (liquid) is collected in the flask.


Revision Notes - Separating by Evaporation

Used to separate a liquid from a soluble solid. Eg Water from Salt. The water is heated and evaporated into the surroundings, leaving the salt behind in the evaporating dish.

Revision Notes - Chromatography

Used to separate a mixture of soluble Inks/Dyes. The ink gets drawn up through the chromatography paper. Ink that is most soluble in the water will move the furthest up the paper. A pencil origin line is used as pencil will not dissolve in water.

Revision Notes - Separating using a Separating Funnel

Used to separate two immiscible liquids. Eg Oil and water. Oil is less dense than water and floats on the water. The tap on funnel is opened and water drained off and collected in a beaker.


Revision Notes - Distillation

Used to separate a mixture of soluble solid and a liquid. However, the liquid can be kept and not lost to the surroundings. Eg. Separating water from salty sea water. First the water is evaporated as steam by heating it, leaving the salt behind, then it is condensed and cooled back down into liquid water.

Revision Notes - Materials and Recycling

Recycling

Recycling means to re-use a material for another purpose or to use it to make a new material.

 

Not all materials can be recycled.

 

Materials need to be recycled

because resources used to make them will run out.


Revision Notes - Properties of Materials

The property of a material is how it behaves or even reacts. Materials are selected to make certain things or be used in a particular way based on their properties.

Biodegradable

If a material is biodegradable it means it will rot away (decay). Organic matter like plants and wood are biodegradable.

Things made from plants and wood are also biodegradable. Cardboard and paper are made from wood so they are biodegradable.

 

Non-biodegradable materials will not rot away and stay in land fill dumps for many years. Plastic is non-biodegradable.

 

Magnetism

One property of some metals like iron and steel is that they are magnetic. Steel cans can be separated from non-magnetic Aluminium cans using magnets.


Revision Notes - Environment & Classification

Animals and plants rely on each other survival.

Plants use light energy from the Sun to produce food by Photosynthesis – Plants are Producers

Animals eat plants for food. Other animals can eat these animals for food too. Animals are Consumers.

This transfer of chemical energy from plants to animals is called the food chain.

Revision Notes - Food Web

A large, varied environment will have many plants and many animals feeding on each other, this is called a food web.

In this food web the plants are the trees and grass.

Some plants are eaten by more than one animal.

 Some of these animals are eaten by more than one other animal.

A food web is just lots of food chains put together.

In this food web if population of Mice die off, the Eagles will eat more Snakes and Frogs.


Revision Notes - Classification

Living things are put into two main groups: Animals & Plants

Animals have 2 main groups: