an Invisible fluorescent ink
Invisible ink refers to any substance which can be
used to write with, which is either invisible on
application or disappears quickly, and can be
subsequently restored by some means. The use of
invisible ink is a form of steganography, and has
been used in espionage.
The simplest forms of invisible ink are lemon
juice and milk. Write on paper with a fountain
pen, toothpick or a finger dipped in the liquid.
Once dry, the paper appears blank. The writing is
made to appear by heating the paper, on a hot
radiator for example. Invisible inks have been
used for secrecy and security for many years.
The Germans in
World War II used invisible inks for secret
writings. One suspected spy was found to have
large numbers of keys in his motel room. After
inspecting the keys it was found that some of the
keys were modified to unscrew at the top to show a
plastic nib. The keys contained special chemicals
for invisible ink! However, codes and secret ink
messages were very easily captured and decoded.
Some of the more fun secret writings are
concealment messages like invisible
inks made out
of potato juice, lemon juice, and other types of
juices and sugars! Deciphering and decoding
messages take a lot of time and can be very
frustrating. With experience, strategies, and most
of all luck, you'll be able to crack lots of codes
information about your project. If you are a basic
or advanced member of ScienceProject.com, your
project advisor may prepare the initial
information that you need and enter them in this
section. In any case it is necessary for you to
read additional books, magazines or ask
professionals who might know in order to learn
more about the subject of your research. Keep
track of where you got your information from.
invisible inks: A substance used as a
fluorescent invisible ink is usually a clear
liquid. You may use a fluorescent invisible ink to
write any thing on paper or almost any other
surface. You know what you write, but others
cannot see it. A UV light can magically make your
writing visible. Most invisible inks can be
revealed only once and remain visible for the life
of the document. Fluorescent invisible inks
however can be revealed as many times as you need
under UV light. Unlike regular
or other invisible inks, they will disappear again as soon
as you turn off the UV light. This gives a special
advantage to fluorescent invisible lights and
opens the doors to many new applications for such
Applications: Invisible fluorescent inks are
use to to mark dollar bills and many other
valuable documents to prevent counterfeiting.
Banks and inspectors of such documents use UV
lights to see the hidden marks in order to verify
legitimacy of documents. Invisible fluorescent
inks are also used to mark other valuable
properties for identification and to proof
ownership in case of theft. Invisible fluorescent
powders and inks are used to detect unauthorized
access and theft. These material will remain on
hands and clothing of the thief and are viewable
under UV light. Clubs and museums are using
invisible inks to stamp visitors hands and use it
to control re-entry.
More about UV
light: UV or Ultra Violet is an invisible part
of light spectrum above blue. UV has a higher
frequency (lower wavelength) than visible lights.
Although invisible, UV has many of the properties
of normal sunlight. UV can cause sunburn, hurt the
eyes and even cause discoloration of material dyed
with organic dyes.
light sources can be used at the crime scene or in
the laboratory for the visualization of several
types of physical/trace evidence. Many human
physiological fluids such as blood, semen, saliva
and urine may fluoresce under ultraviolet light
Other items such as hairs, fibers, latent
fingerprints and even footwear impressions may
fluoresce. Examination may also reveal bruising,
physiological stains and marks which may not be
evident under normal lighting.
(Warning: UV light can damage your retina if the
light source is viewed directly.)
Investigation using UV light:
Since body fluids
like semen, saliva, and vaginal fluids are
naturally fluorescent, the use of a light source
unique method for locating them. A crime
scene investigator can narrow down the specific
locations of stains for collection instead of
testing entire, large pieces of evidence such as a
mattress, a carpet, a sheet, an article of
clothing, etc. The dried body fluids will actually
glow under the UV light illumination.
you want to find out? Write a statement that
describes what you want to do. Use your
observations and questions to write the statement.
What household material can be used as fluorescent
The purpose of this project is to identify
household material that can be used as invisible
Many of you may already have such material at
home. If you donít, you will need to expand your
search to your local grocery store or hardware
think you know what variables may be involved,
think about ways to change one at a time. If you
change more than one at a time, you will not know
what variable is causing your observation.
Sometimes variables are linked and work together
to cause something. At first, try to choose
variables that you think act independently of each
your gathered information, make an educated guess
about the answer to your question or the result of
an experiment to test each hypothesis. Make a
step-by-step list of what you will do to answer
each question. This list is called an experimental
procedure. For an experiment to give answers you
can trust, it must have a "control." A
control is an additional experimental trial or
run. It is a separate experiment, done exactly
like the others. The only difference is that no
experimental variables are changed. A control is a
neutral "reference point" for comparison
that allows you to see what changing a variable
does by comparing it to not changing anything.
Dependable controls are sometimes very hard to
develop. They can be the hardest part of a
project. Without a control you cannot be sure that
changing the variable causes your observations. A
series of experiments that includes a control is
called a "controlled experiment."
Do your experiments after dark. Turn off the
lights. Turn on your portable UV light. Walk
around the home to detect fluorescent material.
Make a list of fluorescent objects and material
that you discover. Find a way to use those
material for secret messages. Inspect all objects,
specially look for fluorescent liquids.
writing secret messages with fluorescent liquids
that you discover. Use a fountain pen or toothpick
for writing. If the fluorescent liquid that you
find has color, use the same color paper to write
invisible message under UV light, before and after
it dries. Record how long does it take for your
newly discovered ink to dry.
The most important device that you need for your
experiment or research is a battery operated
portable UV light. (MiniScience part# UVCLMN). All other
materials such as paper and fountain pen can be
found at home or may be substituted by other
of Experiment (Observation):
are often done in series. A series of experiments
can be done by changing one variable a different
amount each time. A series of experiments is made
up of separate experimental "runs."
During each run you make a measurement of how much
the variable affected the system under study. For
each run, a different amount of change in the
variable is used. This produces a different amount
of response in the system. You measure this
response, or record data, in a table for this
purpose. This is considered "raw data"
since it has not been processed or interpreted
yet. When raw data gets processed mathematically,
for example, it becomes results.
do any calculation for your project, write your
calculations in this section.
what happened. This can be in the form of a table
of processed numerical data, or graphs. It could
also be a written statement of what occurred
It is from
calculations using recorded data that tables and
graphs are made. Studying tables and graphs, we
can see trends that tell us how different
variables cause our observations. Based on these
trends, we can draw conclusions about the system
under study. These conclusions help us confirm or
deny our original hypothesis. Often, mathematical
equations can be made from graphs. These equations
allow us to predict how a change will affect the
system without the need to do additional
experiments. Advanced levels of experimental
science rely heavily on graphical and mathematical
analysis of data. At this level, science becomes
even more interesting and powerful.
the trends in your experimental data and your
experimental observations, try to answer your
original questions. Is your hypothesis correct?
Now is the time to pull together what happened,
and assess the experiments you did.
Questions & Answers:
have learned may allow you to answer other
questions. Many questions are related. Several new
questions may have occurred to you while doing
experiments. You may now be able to understand or
verify things that you discovered when gathering
information for the project. Questions lead to
more questions, which lead to additional
hypothesis that need to be tested.
did not observe anything different than what
happened with your control, the variable you
changed may not affect the system you are
investigating. If you did not observe a
consistent, reproducible trend in your series of
experimental runs there may be experimental errors
affecting your results. The first thing to check
is how you are making your measurements. Is the
measurement method questionable or unreliable?
Maybe you are reading a scale incorrectly, or
maybe the measuring instrument is working
If you determine
that experimental errors are influencing your
results, carefully rethink the design of your
experiments. Review each step of the procedure to
find sources of potential errors. If possible,
have a scientist review the procedure with you.
Sometimes the designer of an experiment can miss