||There is a lack of focus on the
theme of the paragraph. This is caused by the lack of clear topic
sentences at the start of the paragraphs. The topic sentences fail
to set out what the paragraph will discuss.
||... classified as solids.
||The topic sentence for the
gas paragraph informs the reader about examples of gases but does
not introduce what the paragraph will discuss.
||Air, oxygen, and carbon dioxide
are gases and have no fixed shape or volume of their own. Any
container can be filled by these as they diffuse and spread out to
fill them. The atoms or molecules of gases move very rapidly and are
widely spaced. If water is put into a tyre, it will run to the bottom;
if a tyre is filled with air, it fills the whole space inside it.
They therefore expand or compress to fit any area.
||This topic sentence fails to begin
the paragraph with solids before it introduces the concept of crystalline
and amorphous solids.
||Crystalline solids and amorphous
solids are the two classes solids may be further divided into.
When heated, the change to a liquid known as melting is sharp and
clear for crystalline solids. Rocks, wood, paper and cotton are this
type. These are made up of atoms arranged in a definite patternŠ