God made all people different
in the way they walk, in their
stride, and in their steps. If you
walk bowlegged, with your toes out or
in, or if you drag your heels, you leave
behind different footprints.
Footwear impressions have the
potential to leave individual characteristics
under the right conditions, making
them a valuable tool in forensic
investigation. Investigators recognize
two types of characteristics in these
footwear impressions: class and individual.
Class characteristics are group
characteristics such as shoe brand, size,
design, or color. Individual characteristics
are wear marks, cuts, gouges, and
damage to the sole of the shoe.
Watch Unlocking Science on Answers TV for a demonstration of this experiment.
Individual characteristics in shoes are
unique to the individual who wore the
shoe. There is only a one in an octillion
000 or 1 x 1027) chance that two different
people wearing the same shoe would
have the exact same individual characteristics.
That is basically a 0% chance.
In addition to being valuable for helping
investigators solve crimes, our unique
foot impressions remind us of our individual
value to God. If the Creator cared
enough to make our footsteps physically
unique, imagine how he delights in
directing our steps (Proverbs 3:6).
Investigate your own unique foot
impressions and compare them with
the foot impressions of other people.
You will need an adult to help you with this experiment!
- 1 lb. plaster of paris
- 1 gallon plastic
zipper bag per
- 2 cups (about
500 ml) water per
- Aerosol hairspray
- Craft sticks
- Scrub brush, old
- If indoors, a
plastic shoebox or
that your foot (with
shoe on) can step
- Sand/Soil: damp
play sand, damp
beach sand, or soft
clay/dirt mix are
soil contains too
much debris to
make good prints.)
*Do not immerse
any body parts
(hands or feet) in
the mixed plaster
as it can cause
- Have an adult help you with this experiment.
- If outside, clear any debris from a
patch of ground, leaving only the soil.
If inside, fill your shoebox about 1/3
full of soil and remove any debris like
sticks, large rocks, or leaves.
- Select one of your shoes with an
interesting tread pattern on the
bottom. Step (or walk through) the
soil. Observe your shoe print. Is it
clear and complete? If not, clear the
area and follow the procedure until
you have a satisfactory impression.
- Add plaster of paris (1 lb.) to a strong
plastic zipper bag (1 gallon). The bag
needs to be large enough to add
sufficient water when you’re ready to
cast the impression.
- Hold the hairspray can approximately
one foot way from the impression and
lightly spray the impression in a sideto-
side motion. The hairspray will help
hold the soil particles together while
you are pouring the casting material.
- Add the water (about 500 mL) to the
zipper bag and seal it. Knead the bag
until there are no more lumps. Work
quickly because the plaster of paris
will begin to set.
- Open one corner of the bag. Start
approximately 1 inch above one end
of the impression and slowly pour
the casting material just above the
impression. To avoid damaging the
details of the print, do not pour the
casting material directly onto the
impression, but let it flow into the
impression. You should cover the entire
impression as well as about a half- to
one-inch overlap onto the soil around
the perimeter. Discard the zipper bag
and do not wash the plaster of paris
down your drain.
- Break pieces of craft sticks into
2–3-inch pieces and place them on the
impression in all different directions to
give it strength. Do not press the craft
sticks so deep that you damage the
- If outside, the plaster will need to cure
(set) for a minimum of 30 minutes. After
30 minutes, if the plaster is hard to the
touch, carefully pick up the impression,
turn it over, and place on a flat
surface for 24 hours. Do not clean the
impression at this point because further
hardening needs to take place. If you are
inside, simply leave the impression in
the shoebox for 24 hours.
- After 24 hours, use a small paintbrush
to clean your impression by removing
any excess soil.
- Wash the impression with an old
toothbrush or sponge to remove
remaining soil. Don’t rub too much
or you will remove the details.
Comparing the Print
Compare the shoe
you wore to create
the impression and
your lifted impression
side by side. Find five
and five individual
(mentioned in the
introduction). Can you
associate any of the
unique wear marks,
tears, or gouges in
the bottom of your
shoes with certain
activities that you
have participated in?
gait to the gait of
others by walking
through a section
of soil that will
allow you to
leave 3–4 prints.
Examine the prints
and record as
many details as
you can. Notice
(toe to heel), toe
the print is deeper
on the inside or
outside, and any
other features you
Roger Patterson, affectionately known as
Mr. P, helps kids understand science from
a biblical perspective through experiments
and hands-on activities in his Answers TV
show Unlocking Science.
This article is from Answers magazine, October–December, 2021, p. 30–31.