Experiment – 10
The four primary sensations of taste are sweet, sour, salt and bitter. Although some taste buds are situated on the palate, tonsils and in the upper throat, the tongue is the central stage. Its tip is more sensitive to sweetness than any other part because the highest concentrations of sweet taste receptors are located there. Saltiness and sourness hold sway at the sides, the former near the tip, the latter more centrally. All tastes are combinations of the effects by food on the four basic taste receptors, modified occasionally by that made on the ordinary nerve endings, like the sensation of burning.
Without saliva it is impossible to taste anything, a fact which can be proved by the following experiments:
Experiment – 9
Props: Sugar cubes, salt crystals, and a clean piece of cloth.
Method: First wipe your tongue dry and then place the sugar cube or salt crystal on the tongue. It will be tasteless until the mouth begins to water again. Even ice cream is tasteless until it melts.
Experiment – 10
Effect: Odd things happened to your taste buds.
When the taste buds are tired with sweet in the mouth, water tastes saltish. And when the taste buds are tired with sour solution in mouth, water tastes sweet.
Just like the receptor cells of the retina becomes fatigued when exposed too long to a single visual stimulus, those cells that register taste undergo a similar process of distortion.
Props: Strong solution of sugar and water, strong sour solution. Fresh water.
Method: Roll the strong sugar solution around the mouth for several seconds before swallowing it until it tastes less sweet. Next, take a glass of fresh water and taste it. It will taste so salty you will not believe it. What has happened is that the taste buds responsible for sweetness have been phased out temporarily thus giving those responsible for salt extra prominence. In the same way an extremely sour solution will make fresh water taste sweet if sipped immediately afterwards.
In everyday life we experience this. After eating sweets when you drink a cup of tea or coffee, you find the same less sweet. Also, when you eat a gooseberry and immediately drink a cup of water it tastes sweet!
Experiment – 11
Effect: Tasting any sweet you like best by taking deep breaths and concentrating on the taste of the particular sweet.
Props: Saccharin, pencil and paper
Method: Apply a bit of saccharin on your right index finger. Call a volunteer from the audience and ask him to write on a piece of paper the name of the sweet he likes best. Touch the writing with your index finger on which you have applied saccharin. Ask him to put his tongue out, close his eyes and think about the taste of the sweet he has written on the piece of paper while taking deep breaths. After a few seconds while you go on taking the name of the sweet touch the written part to his tongue and he will be surprised that he can actually taste the particular sweet!
This happens when one concentrates on the taste of the sweet one likes best. The taste of the saccharin on the tongue makes the person believe he tastes the sweet which he is thinking of.