The world through our sense

1. Stimuli such as heat cold pain pressure and touch can be detected by the skin
2. sensisitivity of the skin depends on the thickness of the epidermis and the number of receptors
3. The sensory organ of smell is nose
4. Mucus in the nasal cavity dissolves the chemical substances and stimulates the sensory cells
5. The sense of taste is detected by the tongue
6. Certain areas of the tongue are sensitive to specific tastes such as sweet salty sour and bitter
7. The sensory organ of hearing and balance is the ear
8. sound which is produced by vibration is transmitted in the form of sound waves
9. body equilibrium is assisted by the semicircular canalas
10. Air pressure at both sides of the eardrum is balanced by the eustachian tube
11. The sensory organ of sight is the eye which is sensitive to light stimulus
12. All of the sensory organs send nerve impulses via the nervous system to the brain to be interpreted
13. Lights moves in a straight line
14. when light falls on a smooth hard and even surface reflection of light take place.
15. Refraction of light occurs when light travels from one medium to another of different densities
16. an image formed by a convex lens is real and inverted
17. a long sighted person cannot see near objects clearly and this can be corrected by a convex lens
18. a short sighted person cannot see far objects clearly and this can be corrected by a convex lens
19. a short sighted person cannot see far objects clearly and this can be corrected by a concave lens
20. astigmatism which is due to the uneven surface of cornea, can be corrected by a cylindrical lens.
21. the type of vision using only one eye is called monocular vision
22. sometimes what is seen by the eyes is interpreted differently by the brain. this is called optical illusion.
23. the blind spot does not have photoreceptors to detect an image so an object cannot be seen when the image falls on the blind spot
24. the invention of optical devices can help to overcome limitations of sight
25. sound which is a form of energy can be transferred through solids, liquids, and gases but not through a vacuum
26. echo occurs when sound waves are reflected by a hard and smooth surface
27. objects with soft and rough surfaces absorb sound
28. hearing using both ears is called stereophonic hearing which is able to detect the direction of sound
29. hearing defects can be corrected by hearing aids
30. certain parts of plants are sensitive to certain type of stimulli.
31. the way plants respond in certain directions to these stimuli is called tropism.
32. Response of plants toward: Light-phototropism gravity-geotropism water-hydrotropism touch-thigmotropism