Lab Technique I
Making Papier-Mâché
Introduction:
The Chinese are credited with finding that glues combined with paper to make objects that were
fashionable and durable. The French named the craft papier-mâché, which means chewed paper. It reached its
height of popularity in the 18th century. Paper at that time was hand made and very precious. Making objects out of
papier-mâché was a creative means of recycling this commodity. The Industrial Revolution put an end to the use of
papier-mâché as a functional craft, however many papier-mâché objects made 200 years ago are still around and
are as attractive today as when they were made.
Purpose:
Through the art of papier-mâché the students will learn and demonstrate the following techniques:
1) reading and following directions
2) use of balance to find mass
3) use of graduated cylinder to determine volume
4) use of Bunsen burner
5) folding filter paper and filtering
Safety:
Wear goggles and apron
Confine long hair and loose clothing
Hot glass looks like cool glass
Materials:
600 mL beaker
aluminum foil
balance
ring-stand
wall-paper paste
liquid white glue
newspaper
1graduated cylinder
stirring rod
funnel
ring-clamp
paint
brushes
coffee filter
Bunsen burner
tubing
striker
fork
sand paper
wash bottle
wire-gauze
Procedure:
1.
Use a balance to mass 11 g of newspaper strips into a 600 mL beaker. Before using the balance check to
see that the pointer is resting at zero. If the pointer is not at zero, check the slider weights to see if there all at zero.
If all the sliders are at zero, then turn the adjust knob (usually located at the far left end of the balance beam) until
the pointer rests at zero. Never place chemicals or hot
objects directly on the balance pan.
Place the 600 mL beaker onto the pan and determine the
mass of the beaker. To determine the mass you began with
the largest slider placing it over until the pointer goes does,
then taking it back one step. The pointer should be pointing
up. Repeat the process with each slider until the pointer is at zero. To determine the mass add up each slider.
Record the mass of the beaker.
Add 11 grams to the balance by sliding over the weight of the 10 grams scale one place and the weight of the 1-gram
scale one place. Add the newspaper to the beaker until the pointer is once again at zero.
Record the mass of the beaker and newspaper to the nearest 0.01 g. Return all sliders to zero and remove the
sample. Make sure the balance pan is left clean.
2.
3.
4.
Using a 100 mL graduated cylinder add 500 mL of water to the beaker and
newspaper. To use a graduated cylinder add water to the 100 mL mark.
The
volume is always read at the bottom of the meniscus with your eye at the
same
level as the liquid surface. The meniscus is the curbed surface of the water
when
the water contacts the cylinder walls. Repeat measuring out the water until
you
have a total volume of 500 mL.
Label the beaker and let it sit until next class period. The mixture is called
mash.
Boil the mash for20 minutes. To boil the mash you will need to use a Bunsen burner. Each burner has
a gas inlet located in the base, a vertical tube, adjustable opening or airports in the base of the barrel,
and an adjustable needle valve located underneath the bottom of the base. To light the burner, connect
the burner to the gas outlet using tubing. Partially close the airports at the base of the barrel and the
needle valve should be barely open. Turn the gas on at the outlet and hold the sparker about 5 cm
above the top of the burner and proceed to light.
You adjust the height of the flame by adjusting the amount of gas that is flowing into the burner. You
adjust the color of the flame b changing the amount of airflow through the airports. If there is not
enough air the flame will be yellow. This is an inefficient flame and your glassware will be black wit
soot if you use this flame in laboratory work. It is also a
cool flame, which means it will take a longer period of time
for you to heat the mask to boiling.
The ideal flame is about 8 cm in height, blue
in color and ahs a double cone. The hottest
part of the flame is at the top of the inner
cone.
To boil the mash you must first set up a ring stand with ring clamp and wire gauze. The
beaker goes on top of the wire gauze and the burner goes underneath. The top of the
inner cone should be touching the bottom of the wire gauze. If you have it higher or
lower you are not being efficient and it will take a longer time for the mash to boil.
5.
6.
Using a fork whip the mash until it is soft and pulpy.
Set up a ring stand with a ring clamp and clay triangle. The funnel will sit in the clay triangle. Obtain
a coffee filter. Fold it along its diameter - in half and
then
fold it again in half to form a quadrant. Separate the folds
of the
filter, with three thicknesses on one side and one on the
other,
then place it in the funnel. The funnel should be wet
before
the filter is added. Use your wash bottle and wet th4 filer
paper
with a little water and press the edges firmly against the
sides
of the funnel so no air can get between the funnel and the
filter
paper.
Do not completely fill the filter with the liquid. It must
never
overflow. Try opt establish a water column in the stem of the funnel, thus excluding air bubbles, and
then add the liquid just fast enough to keep the level about 21 cm from the top of the filter.
When a liquid is poured from a beaker or other container it may adhere to the glass and rundown the
outside wall. This may be avoided by holding a stirring rod against the lip of the beaker. The liquid
will run down the rod and drop off into the funnel without running down the side of the beaker.
Place the pulp in the funnel and let the water filter out. Squeeze the pupil gently until it is a soft moist
lump.
7.
Put the pulp back into the beaker. Using a 10 mL graduated cylinder stir in 8.5 ml of liquid white glue
and 8.5 mL of wallpaper paste. Stir until the mixture is not lumpy.
8.
Using the aluminum foil fashion an armature (skeleton on which the papier-mâché is molded) of your
choice. REMEMBER NOTHING VULGAR OR UNSEEMLY!!
9. Apply the mash to the armature and sculpt the figure of your choice.[HINT: KEEPING YOUR
FINGERS WET HELPS SPREAD THE MASH EASIER ONTO THE ARMATURE]
10. Place your finished project in the designated spot and leave until the next class period.
11. Sand your figure, paint and leave to dry.
Data:
Measurements:
Mass of beaker
Mass of beaker and newspaper
Mass of newspaper
Volume of water
Volume of white glue
Volume of wallpaper paste
Observations
Draw set up of Step 6 include type of flame used
Mash before heating
Mash after heating
Mash after whipping
Describe the filtrate
( liquid in beaker after filtering)
Describe the pulp
Sketch the armature you used
Turn in your armature.
Questions:
1. As soon as you enter the lab, what safety equipment should you put on immediately?
2.
Why was it important to accurately find the mass of the newspaper?
3.
What type of flame is preferred for laboratory work and why?
4.
What difference is there between an efficient burning Bunsen burner and one which is burning inefficiently?
5.
Susie decided not to squeeze the extra water from the pulp. How would this have affected the outcome of her papiermâché?
6.
What was the role of the glue in this process?
7.
Which graduated cylinder did you use to measure out the volume of the glue? Why?
8.
How can a liquid be transferred from a beaker to a funnel without splattering and without it running down the outside
wall of the beaker?
9.
Turn in your papier-mâché – remember to put your name and period number on it
Conclusion: