Chapter: SCIENCE EXPERIMENTS & AMUSEMENTS FOR CHILDREN BY CHARLES VIVIAN. Simple Technical Steped Practical Projects for school and college students.
How a Filter Works
How a Filter Works
You will need: Blotting paper, paper clip, water
and glass, sand, salt, sugar, ink.
When you turn on the faucet
and fill a glass with water you must have noticed how clean and sparkling the
water looks. This is because it has been filtered and chemically treated to
remove impurities, for impure drinking water can cause illness.
When you stir sand into
water it never dissolves, but remains suspended in the water. A filter can be
used to remove suspended substances from liquids, but it cannot remove
dissolved matter, such as salt.
You can make a simple
filter by cutting a circle of blotting paper about 5 inches in diameter, and
making a straight cut into this circle from the outside to the center, as shown
in the diagram.
Form several shallow cones
from the blotting paper, securing the ends with a paper clip. Place a cone in
the top of a glass.
Now try the effect of your
filter on a sand-water mixture; on a salt mixture; on a sugar mixture; on an
ink-and-water mixture, etc. You must use a fresh filter cone each time, of
course. It will be easy for you to discover which are the suspended substances
and which have been fully dissolved.
Related Topics