Taste Threshold

Science Independent Project

taste threshold Practical Report

hYphothesis
The lesser the concentration of the solution, the lighter its taste become. The result will be subjective.
Aim
The aim is to determine an accurate common threshold of taste for sweetness, sourness and saltiness by determine what is the lowest concentration of a solution that still has perceptible taste for salt, sugar and vinegar.
Risk Assessment Risk | Mitigation | 1. Injury from broken glass cylinder. | Wear safety glove, handle cylinder carefully. | Water spills on the floor -> slippery floor. | Handle container carefully, wear safety footwear. | EQuipment * salt * table sugar (sucrose) * vinegar * water ( distilled) * spoon * gram scale * 100 mL graduated cylinder * 10 mL graduated cylinder * Ear buds * cup * paper towels * notebook & pen

METHOD
- The solutions should be taste by more than 1 person for more accurate results.
- Make a data table in your notebook like the one below. Substances | 10% | 5% | 1% | 0.1% | Table sugar (sucrose) | | | | | Salt | | | | | Vinegar | | | | |

1. Measure 720ml of distilled water and pour it into a cup. Add 80g of sugar. Stir until dissolved. This gives you a 10% (weight/weight) sucrose solution. Note any other observations that you make. 2. Rinse your mouth with water and wipe your tongue dry with a clean paper towel. 3. Dip a clean ear bud into the 10% sugar solution and taste it with the tip of your tongue. If you can taste the sweetness, put a “+” in your data table for 10% sucrose. Note any other observations that you make.

4. Now measure out 80 ml of the 10% sucrose solution and pour it into a clean paper cup. Add 720ml of distilled water and stir. (Use a clean stirrer, or else thoroughly rinse and dry the previous stirrer, so that you don 't carry over concentrated solution into the dilute solution.) This will give you a 1% sugar solution. 5. Again rinse your mouth with plain water and wipe your tongue dry with a clean paper towel. 6. Now dip a clean ear bud into the 1% sugar solution and taste it with the tip of your tongue. If you can taste the sweetness, put a + in your data table for 1% sucrose. Note any other observations that you make. 7. To make a 5% solution, replace half of the 10% solution with 400ml of water 8. To make a 0.5 %solution, replace half of the 5% solution with 400ml of water. 9. Continue making serial dilutions, rinsing and drying tongue, and testing each new solution with the ear buds procedure. Record the results in notebook. The lowest concentration at which you can still taste the sweetness is your approximate taste threshold.

10. Repeat the experiment with salt and vinegar.

Variables
Independent: The concentration of the solution.
Dependant: the taste threshold for different type of tastes and different concentration.
Control: weight of the solution (800g).

Result/Observations * Tested on subject 1: Male, 16 years old, healthy * Test on subject 2:Male 15 years old, healthy * Test area: tongue tip. Substances | 10% | 5% | 1% | 0.5% | Table sugar (sucrose) | + + | + + (slightly reduced) | + -(greatly reduced) | * - | Salt | + + | + + (reduced, but stronger than sugar and vinegar) | + + (greatly reduced but still stronger than vinegar and salt) | * - | Vinegar | + + | + + (slightly reduced) | + + (greatly reduced) | * - |
+: perceptible
-: imperceptible

Analysis
The result completely supports the hypothesis. As seen, to both subjects, salt tastes stronger than sugar and vinegar. The difference in taste with 1% sugar solution shows that taste sensitivity is different from person to person. Because taste sensitivity is different from person to person, the result of the experiment is fairly subjective. In order to determine a common taste threshold, an experiment with larger sample of people is necessary.

Conclusion

From this experiment, it can be seen that the result does not support the aim, it is impossible to determine an accurate common taste threshold.

References

1. Ideas from “MEASURING YOUR TASTE THRESHOLD”:http://www.sciencebuddies.org/science-fair-projects/project_ideas/HumBio_p013.shtml

Photographic Evidences

References: 1. Ideas from “MEASURING YOUR TASTE THRESHOLD”:http://www.sciencebuddies.org/science-fair-projects/project_ideas/HumBio_p013.shtml Photographic Evidences