Now blindfold the otherperson taking partin the experimentand go
throughthe sameprocedure.
You will observe:Thetasterwill recognize severalofthe foods by taste
alone, but not all of them. Some he willnotbe able to identify.
Whatwe thinkofas the"taste"of most foods is really acombinationof
taste and smell. When you hold your nose while tasting,ofcourse youcannot
experience thecharacteristicsmellofthe food. Perhapsyou have noticedthat
when you have a cold-andyour nasal passages are clogged-foodseems
tasteless. Now youunderstandwhy this is so.
DISTINGUISHING TASTE AREAS OF THE TONGUE
Materials: Sugar, salt, an aspirin tablet, four drinkingglasses, a small
amountof vinegar, tap water, a boxoftoothpicksorcottonswabs.
Follow thisprocedure:In eachoffour glassesprepareoneofthe following
mixtures: a 5%solution of sugar (sweet); salt solution; an aspirin tablet
dissolved inhalfa glass of water (bitter);a 50%vinegarsolution(sour).
Before you try thisexperiment,whetheronyourselfor acompanion(it's
more fun to work with a friendthanalone), wipe yourtonguedry with a clean
piece ofpapertissue. This willpreventsaliva fromtransferringtestsubstances
from the spot where they are applied tootherpartsofthemouth.
First, dip a toothpickin the sugar solution. Before you taste, roll the
toothpickaroundthe rimofthe glass to remove excesssolution. Touchthe
toothpickto the tip, middle, the edges and the back of the dry tongue. Note
on a pieceofpaperon whichpartofthe tongue thesensationofsweetness
wasstrongest.
Now, rinse yourmouthwith cold tap water. Dry your tongue. Using a
newtoothpickapply the saltsolutionto the same areasofyour tongue. Use
the samemethodfor testing the aspirin and vinegar solutions.
Be sure to use a cleantoothpickfor eachsolution,to rinseyourmouth
and to dryyourtongue aftereach taste.
Youwillobserve:Sour tastes arestrongestat theouteredgesofthetongue,
while the taste ofsalt is felt most sharply at the tipandat the edges. Bitter
tastes are sensed most keenly at the backofthe tongue, and the sweet taste
is mostnoticeableat the tip.Sweet, sour,bitterand salty are the only food tastes to which thetongue
is sensitive. Certainareasofthetonguereact to each, because the taste buds