SCF3C1_Limitations.pdf

Limitation of Senses 1. Humans cannot see bacteria with the naked eyes, neither can we see the surface of moon clearly. 2. This means our sense of sight has limitations. 3. The limitation of senses is the limitation of our body to detect stimuli. 4. Sometimes, the limitation of senses is due to...

Limitation of Senses 1. Humans cannot see bacteria with the naked eyes, neither can we see the surface of moon clearly. 2. This means our sense of sight has limitations. 3. The limitation of senses is the limitation of our body to detect stimuli. 4. Sometimes, the limitation of senses is due to the defects in the sensory organs or the process of ageing which affects hearing and sight in humans. 5. Let us explore the limitations of sight and hearing. Limitation of Sight There are two types of limitations of sight, they are, optical illusions and blind spots. Optical illusion 1. Optical illusions make what we see different from the true situation. 2. The brain cannot make accurate interpretations of the information sent by the receptors in the eye. 3. Figure 1.16 below shows a few examples of optical illusions The blind spot 1. The eyes cannot detect an image that falls on the blind spot. 2. The blind spot is the part of the retina that is not sensitive to light. 3. Image cannot be seen because the blind spot does not have photoreceptors. 4. What causes limitation of sight? 5. Limitation of sight can be caused by the following factors: Defective eyes Ageing 6. For a person with normal vision, light which enters the pupil falls on the retina. 7. Conditions that affect vision include: short-sightedness long-sightedness astigmatism presbyopia. 8. To solve the problem above, corrective measures can be taken to restore a clear vision. Limitations of Hearing 1. Similar to the sense of sight, the sense of hearing also has its limitations. 2. Human can only detect sounds in the frequency range of 20 Hz to 20 000 Hz. 3. What causes hearing to be affected? Ossicles in the middle ear fused together due to infection Inelastic eardrum due to ageing  Constant exposure to sounds and loud music can damage the sound receptors in the cochlea. 4. Can limitations of hearing be overcome? 5. There are several ways to improve the sense of hearing. 6. A person who has partial hearing loss can still hear with corrective measure but if a person is completely deaf, corrective measures cannot be used. 7. A person’s hearing can be improved through surgery or by wearing a hearing aid. A hearing aid can amplify the sound to make a person hear better Technology and Inventions to Overcome Limitations of Senses 1. There are also many other instruments to overcome limitations of sight and hearing. 2. Some of the instruments created by scientist to overcome limitations of sight and hearing can be seen below: