Experiment

(1) An Experiment to Determine the Effect of Saliva on Starch.

Materials Required:

• Test tubes, iodine solution, boiled rice, boiled and chewed rice, dropper, water

Procedure:

• Take two test tubes. Label them ‘A’ and ‘B’.
• In test tube ‘A’ put one teaspoonful of boiled rice; in test tube ‘B’ keep one teaspoonful of boiled rice after chewing it for 3 to 5 minutes.
• Add 3–4 ml of water in both the test tubes.
• Now pour 2–3 drops of iodine solution in each test tube and observe.

Observation:

• There is a change in colour in test tube A.
• There is no change in colour in test tube B.

Conclusion:

• There is no change in colour in test tube B as starch has been broken down into simple sugars by saliva.

(2) An Experiment to Determine the Location of Different Types of Taste Buds of a Tongue.

Materials Required:

• Sugar solution, common salt solution, lemon juice, juice of crushed neem leaf or bitter gourd, toothpick

Procedure:

• Prepare a separate sample each of (i) sugar solution, (ii) common salt solution, (iii) lemon juice and (iv) juice of crushed neem leaf or bitter gourd.
• Blindfold one of the person and ask her/him to take out the tongue and keep it in straight and flat position.
• Use a clean toothpick to put the above samples one by one on different areas of the tongue.
• Use a new toothpick for each sample.

• Ask the person which areas of the tongue could detect the sweet, salty, sour and bitter substances.
• Note down the observation.

Observation:

• The person who was blindfolded was able to identify the taste of all the samples in different areas of the tongue like sweet, sour, salty, and bitter as shown in the above given picture.

Conclusion:

• A person can taste different types of food because of the presence of taste buds in different locations of our tongue.