As part of the National Chemistry Week Celebration
(October 21 - 27, 2012)
Ask students in grades 6 through 8 to investigate:
“Smart Paper – How does it work?”
Carbon paper was commonly used between sheets of plain paper to make a copy of
writing on the top sheet by transferring ink to the bottom sheet. Carbonless copy paper
is now used for the same purpose, i.e., to copy what is written on the top sheet to the
bottom sheet, without using a middle sheet of carbon paper. Look for examples of
carbonless copy paper and understand how it works by making your own Smart Paper.
Follow the instructions below and answer the questions.
Pieces of: Newspaper, plain white copy paper, grocery receipts, ATM or
library receipts
Plastic Wrap
Small clear plastic disposable cups
One shallow container, e.g., a cereal bowl
Small saucepan with cover
Mixing bowl
Red cabbage (1/2 head)
Tap water
Coffee Filter Paper
Bath Beads (any brand, about 1/4 cup)
Glue Stick
One sheet of plain white copy paper
Cotton Swabs (e.g., Q-Tips)
Measuring spoons and cups
Plastic stirrers
Paper towels
Look for Carbonless Copy Paper:
a) Place the pieces of paper (newspaper, receipts, etc.) on a clean piece of
plastic wrap.
b) Use a toothpick to mark (i.e., scratch) the surface of each piece of paper and
check to see if scratching the surface left an ink mark. Record your results.
c) Wet the cotton on a swab and touch the surface of the piece or pieces of
paper that showed an ink mark on scratching. Record your observations.
With an adult helper, make Red Cabbage Juice by doing the following:
a) Peel off six big cabbage leaves and tear into small pieces.
b) Add the cabbage pieces to the saucepan and add tap water to cover the
c) Cover the saucepan and heat on a stove (on High) until the water boils.
d) Lower the heat on the stove (to Medium Low) and continue to boil the water
for 15 minutes.
e) Turn off the heat and allow the saucepan to cool.
f) Pour the contents of the saucepan into the strainer placed over the mixing
bowl and collect the cabbage juice.
g) Discard the cabbage pieces in the strainer.
Make the Red Cabbage Indicator Paper:
a) Pour cabbage juice into the shallow container, to just cover the entire surface.
b) Fold the coffee filter twice to make a triangular shape that is four sheets thick.
c) Place the folded coffee filter in the cabbage juice and push them under the
liquid so the folded filter is completely covered with the juice.
d) After 10 minutes turn the folder filter upside down.
e) After another 20 minutes, remove the folded filter from the juice, allow excess
juice to drip back to the container, and place the folded filter on a clean piece
of plastic wrap.
f) Leave the folded filter on the wrap until it is completely dry; this will usually
take at least one hour.
g) Open out the filter and cut along the folds to get four pieces of Red Cabbage
Indicator paper.
Make the Bath Bead Sheet:
a) Cut a piece of plain copy paper to the same size and shape as one piece of
Red Cabbage Indicator paper.
b) Cover the surface of the copy paper with glue using the glue stick.
c) Use a teaspoon to sprinkle bath beads on the copy paper such that the
surface is covered evenly with the beads. This step should be done quickly,
before the glue dries, so the bath beads will stick well to the copy paper. The
covered paper will be your Bath Bead Sheet.
Test your Smart Paper:
a) Place the Bath Bead Sheet on a piece of clean plastic wrap with the beads
facing up,
b) Place two pieces of Red Cabbage Indicator paper on top of the Bath Bead
Sheet. The combined sheets of paper will be your Smart Paper.
c) Use a toothpick to mark (i.e., scratch) the surface of your Smart Paper and
see if you detect any change. Record your observations.
d) Wet the cotton on a swab and touch the surface of the top sheet of paper.
Record your observations.
 Where does the ink come from in the carbonless copy paper? Why is it
released only when the surface is scratched?
 Did you see any change in color when you scratched the surface of your
Smart Paper?
 What happened when you added some water to the surface of your Smart
Paper using the cotton swab? Can you explain what you saw? Why did
you not see a similar change for the carbonless copy paper when you
touched the surface with a cotton swab?
 Which type of color changing paper do you think is better for use in a store
or library, i.e., the carbonless copy paper or your Smart Paper? Explain
your answer.
To complete your entry send us:
1. Written answers to all the questions and your data table.
2. Please complete the entry form (Chemistry Contest Entry Form) and attach it to
your entry. Entries should be postmarked by Friday, November 9, 2012.
3. Send your entry with a self-addressed stamped envelope (refer to Chemistry
Contest General Information for details) to:
Dr. Mark Waner
Department of Chemistry
John Carroll University
1 John Carroll Boulevard
University Heights, Ohio 44118
Teacher Hint: If this activity is being done in a classroom setting, one head of red
cabbage should provide sufficient indicator for one class.