PHYSICAL CHANGES 22/5
Understand that a physical change is a change in state,
shape, or size, without the formation of a new substance.
a) Most objects around us are not pure substances but
mixtures. A mixture is two or more parts blended together yet keeping their own
properties. Mixtures can be separated using their physical properties like
size, shape, color, volume, density, and state. This is called a physical
separation. Using a filter to separate a mixture of different-sized matter is
one example. A filter is a tool used to separate things by size.
b) Some mixtures are not easily separated. These are called
solutions. A solution is a mixture in which the substances are completely
blended so that the properties are the same throughout. The substances are
mixed evenly so they stay blended. When one material forms a solution with
another material, we say it dissolves. Some solids dissolve in water and some
do not. Solubility is a measure of the amount of a material that will dissolve
in another material. Liquid solutions are usually transparent, evenly colored,
and never separate into layers.
Revise chemical and physical change
Changing matter – physical (ice – water- water vapour)
http://www.bgfl.org/bgfl/custom/resources_ftp/client_ftp/ks3/science/changing_matter/index.htm
Reversible or irreversible changes:
http://www.bbc.co.uk/schools/scienceclips/ages/10_11/rev_irrev_changes_fs.shtml
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