When you squirted the sol into the sulfuric acid, thedarkblue became lighter
and finally turned white. The sol was changing into a thread of rayon. After
washing and drying this thread, it can be used for sewing.
Thetransformationof the sol into rayon cameaboutthroughthe reaction
between the sol and the sulfuric acid. The method you used to make rayon in
this experiment is thecuprammoniummethod.Chopped-upwood is the source
ofcellulose in the commercial application of this method.
HOW TO MAKE YOUR OWN TOOTHPASTE
Gather these materials: Powdered calciumcarbonate(CaCOa) ; powdered
orrisroot;sodiumbicarbonate(NaHCOa) ;essence ofpeppermint;an empty
toothpastetube; a small bowl; ateaspoon;a pair of heavy-duty scissors; and
an eye dropper.
Follow this procedure:Straighten thetoothpastetube. With the scissors, cut
off the flatbottomend of it. Rinse the tube out very carefully, including the cap.
Replace the cap but pull the other endapartto make a wider opening. Set the
tube aside to dry. In the small bowl, mix 2 teaspoonfuls of powdered calcium
carbonateand 2 teaspoonfuls ofpowdered orris root. Addi-teaspoonful of
sodiumbicarbonateand 3dropsofessenceofpeppermint. Add water to this
mixture, a drop at a time, stirring it constantly until a paste forms. Put the paste
into the empty tube by the teaspoonful. Before trying to squeeie thetoothpaste
from the tube, close the open end by folding it up several times.