(1)The figures are fixed by the temperature of melting ice and
the temperature of boiling water.
(2)In order to fix the figures on a thermometer,we place the
bulb in melting ice and mark at the level of the mercury,and
call this point 0.
(3)Then we place the bulb in steam and the mercury goes up in
the tube,becaus it expands when it gets warm.
(4)We divide the space between the two marks into 100
divisions which are all the same size,for a Centigrade
thermometer.
(5)As soon as you open the bottle,they start to spread out
into the air,and you can smell the perfume at the other end of
the room.
(6)In the end,when the molecules are spread out evenly inside
and outside the bottle,the spreading out of molecules stops
happening.
(7)According to the laws of spreading out of molecules,the
process goes on without stopping until the concentration
ofperfume molecules is the same all over the room.
(8)This gas turns lime-water cloudy.
(9)When animals breathe in,they take in air and the blood
takes up oxygen from it.
(10)The body then gets rid of this carbon dioxide by breathing
out.
(11)They started rubber plantations in countries with hot,wet
weather conditions,but these still could not give enough raw
rubber to meet the needs of growing industry.
(12)They make artificial,man-made rubber in factories by a
complicated chemical process.