Question 19

Blindfolded students can effectively determine the distribution of touch receptors in the skin.

This experiment allows for the assessment of tactile sensitivity in different areas of the skin by using a bristle as a stimulus. By using a blindfold, the focus is solely on the sense of touch, which is essential for determining receptor distribution.

A) Have a student spin a card composed of many colors and note how long it takes for the colors to merge

This option is unrelated to the distribution of touch receptors as it focuses on visual perception rather than tactile sensitivity. The experiment does not involve any interaction with the skin or touch stimuli, making it ineffective for the intended purpose.

B) Have a student place one hand in hot water, the other in cold, then both in warm water

While this experiment does involve the skin and temperature sensitivity, it does not specifically measure the distribution of touch receptors. Instead, it assesses thermal perception rather than tactile discrimination, which is not the objective of the question.

C) Have a student register the taste of small cubes of distinct foods with eyes closed and nose held tightly

This option pertains to the sense of taste, completely ignoring the tactile system. It does not investigate touch receptors at all, making it irrelevant in determining their distribution on the skin.

D) Have a blindfolded student tell when a bristle placed lightly against the skin is felt

This option directly addresses the distribution of touch receptors by testing tactile sensitivity in specific areas of the skin. The use of a bristle provides a clear stimulus to measure the ability to perceive light touch, which is crucial for this investigation.

Conclusion

Option D is the only choice that effectively tests the distribution of touch receptors in the skin by measuring the sensitivity to light touch. All other options either focus on different sensory modalities or do not involve tactile stimuli, making them unsuitable for determining the specific objective of receptor distribution. Thus, D is definitively the correct answer.