If you take a fluid (i.e. air or water) and heat it, the portion that is heated usually expands. The same mass takes up more volume and as a consequence the heated portion becomes less dense than the portion that is<span><span> not heated.</span> </span>
Anything less dense than water will float, like oil. Anything more dense than water will sink, like rock.
They should look for <span>a report from an independent scientific research firm,
even if they have to pay for it.
In preparing its report, the firm would have already surveyed many of the </span>
<span>citizens from several other towns that currently add fluoride to their water,
plus a lot of other relevant medical research on the subject.</span>
Have the 6 characteristics of living things
1.movement/growth
2.reproduction
3.made of 1 or more cells
4.sensitivity
5.excretion
6.nutrition