Listed below are some experiments
that may perk some interest in those who want a simple home
activity to supplement what you've learnt from this site. If
you click on 'print', next to an experiment, you will open up
a text file which allows you to print only the text:
Try this simple test to see if different types of ink are
chemically the same.
You will need: felt pens; paper towel; scissors; water.
1. Collect several different types of black felt pens (permanent
markers do not work). For the experiment, use two of each
type of black pen.
2. Cut separate strips of paper towel, each about 2cm wide
- two strips for each pen.
3. Mark each strip of paper towel with a dot and record in
your book, which pen you used to make the dot.
4. Using one strip at a time, dip each strip in the water.
Dip the paper towel to just below the dot, making sure that
the dot stays above the water. Allow the water to soak up
the strip and observe what happens to the ink.
5. When all of the strips have been dipped into the water,
see if you can match up the marks made by each type of pen.
Check if what you matched from observations was the same as
the results for your record of the pens.
This is a basic memory experiment to see if you would make
a good witness.
You will need: magazines; scissors
1. Find a variety of different magazines and cut out pictures
of different people's faces (try to make these of a similar
size) - ensure the faces are whole, including mouth, nose,
eyes, face and hair.
2. Cut each face up into the separate facial features and
mix these up.
3. Ask your friend to make a face out of these bits and pieces,
then take 10 seconds to try remembering it.
4. Replace the chosen facial pieces back amongst the pile
of other nose, mouths and eyes etc. Now try to remake the
same picture your friend showed you.
5. To help encourage interest, teachers may even wish to
hold a small tournament of who can make the most accurate
composites (the term used to describe this method of piecing
together a suspect's face).
There are many ways of developing fingerprints, below is
one experiment that uses iodine as a method of developing
fingerprints.
You will need: filter paper; a paper clip; iodine crystals;
string; jar
1. Make a fingerprint on a small piece of filter paper by
firmly pressing down.
2. Take a paper clip with a piece of string attached to it
and clip this on to the filter paper. Place a few iodine crystals
on the bottom of a screw top jar.
3. Hang the paper clip and filter paper inside the jar and
put the lid on tightly trapping the string out the side of
the jar and suspending the paperclip and filter paper.
3. After about ten minutes, the iodine will develop the print
on the filter paper and the image should be clear enough to
photograph.
Alternately, fingerprints can also be easily revealed by
brushing a fingerprinted surface with iron filings or lifting
it from a surface with adhesive tape - neither require 'developing'.
Also a method of developing fingerprints is via the use of
superglue fumes. Below is an approach that may be used:
You will need: superglue; aluminium foil; a cup of hot water;
a weak heat source such as a lamp; a fuming chamber (may be
an enclosed cardboard box which can contain the fingerprinted
medium).
1. Set up the lamp in the corner of your fuming chamber and
cover over the light bulb with a piece of aluminium foil.
2. Carefully spread some superglue over the outer side of
the foil - DO NOT USE FINGERS.
3. To increase the humidity within the fuming chamber, place
a cup of hot water into the box, next to the lamp. This will
create the necessary 'fumes'.
4. After self fingerprinting an object such as a simple sheet
of paper or a plastic slip, place this object into the fuming
chamber with the lamp and water. Tightly shut the lid to allow
the fumes to develop the prints.
5. Remove the lid after 10-15 mins, check that -the prints
have developed. If they have not, try placing more superglue
on the foil or decreasing the size of the fuming chamber so
that less space is present. If you have placed too much superglue
on the foil or left the print inside for too long, the fingerprint
will become covered with a white and snowy looking layer.