1. The World through Our Senses 1.1 Sensory Organs 1.2 Sense of Touch 1.3 Sense of Smell 1.4 Sense of Taste 1.5 Sense of Hearing 1.6 Sense of Sight 1.7 Light and Sight 1.8 Sound and Hearing 1.9 Stimuli and Responses in Plant Teacher Nurul

2. 1.1 Sensory Organs Sensory Organs and Their Stimuli How do we know what is going on around us? Humans have five senses. help us to detect objects and the changes in the surroundings. Our five senses are the sense of sight, smell taste hearing sight touch

3. 1.1 Sensory Organs Sensory Organs and Their Stimuli Sensory organs Stimuli Found in parts of the body Changes/ objects that can be detected by our senses Let’s go to the garden!

4. 1.1 Sensory Organs Name the sense and the sensory organ in each of the photographs.

5. 1.1 Sensory Organs Stimuli Sense ( deria ) Sensory organ Touch, heat, cold, pain & pressure Cold Skin Smell or odours Chemical Nose Sweet, sour, bitter & salt Chemical Tongue Sound Sound Ear Light (brightness or colour) Light Eye

7. 1.1 Sensory Organs Stimulus Receptors in Sense organ Nerves Brain Nerves Response Pain response Skin nerve Brain nerve Effectors (Muscles, glands)

8. 1.1 Sensory Organs The Pathway from Stimulus to Response

9. 1.1 Sensory Organs

10. 1.1 Sensory Organs

11. 1.2 Sense of Touch

12. 1.2 Sense of Touch The organ that detect touch sense is skin. Skin give respond to stimuli like touch, pain, heat, cold and pressure. Our skin is 2mm thick and consists of 2 layers which epidermis and dermis. The sensitivity of the skin depends on the number of sensory receptors and the thickness of the epidermis.

14. 1.2 Sense of Touch 1 2 3 4 5 6 7 8 Pain receptors Touch receptors Heat receptors Cold receptors Pressure receptors

15. 1.2 Sense of Touch

16. 1.2 Sense of Touch Stimulus Receptors in Sense organ Nerves Brain Nerves Response How do the boy do after holding the hot pan? Describe the pathway from stimulus to respond.

17. 1.3 Sense of Smell

18. 1.3 Sense of Smell Nose is the sensory organ of smell . Sensory cells are found in the upper roof of the nose cavity. Smell from chemical substances dissolves in the mucus of the nose. Mucus in the nose stimulates the sensory cells of smell and sends impulses to the brain through nerve cells.

19. 1.3 Sense of Smell Air Sensory cells Nasal cavity Nostril

20. 1.3 Sense of Smell How do our nose detect smell???... Smells are carried by certain chemicals in the air. When we breathe, these chemicals go through our nose. It will then dissolve in mucuos – the moisture layer that covers the smell receptors on the upper part of the nose. The dissolved chemicals stimulate the smell receptors . The stimulated smell receptors then send messages to the brain. The brain identifies the smells. touch smell taste hearing sight

21. 1.3 Sense of Smell Chemical substance Smell reseptors dissolve in mucus Nerves Brain (interpret the massage) Nerves Smell is identified

22. 1.4 Sense of Taste

23. 1.4 Sense of Taste The tongue is the sensory organ of taste . Our tongue able to detect and differentiate different taste such as sweet, salty, sour and bitter.

24. 1.4 Sense of Taste When we eat or drink, foods or drinks dissolved in saliva are detected by the taste receptors in our tongue. On the surface of tongue has groups of sensory cells called taste buds for detecting different tastes. Different areas of the tongue are more sensitive to specific tastes.

25. 1.4 Sense of Taste bitter sour sour salty salty sweet

26. 1.4 Sense of Taste Chemical substance (food) Taste reseptors dissolve in saliva Nerves Brain (interpret the massage) Nerves Taste is identified

27. 1.4 Sense of Taste All our senses work together, but the sense of smell and taste are special partners. When we eat, our nose smells the food and our tongue gives us the taste of the food. Together, they help us to sense most, if not all, of the flavors contained in the food we eat. Will the food taste as good as it normally does when our nose is blocked?

28. 1.4 Sense of Taste It difficult to taste the food you eat when you get a flu.

29. 1.5 Sense of Hearing

30. 1.5 Sense of Hearing Ear is the sensory organ of hearing. Our ear has 3 main parts: a. the outer ear , filled with air b. the middle ear , filled with air c. the inner ear , filled with liquid

31. 1.5 Sense of Hearing Outer ear Middle ear Inner ear

32. 1.5 Sense of Hearing pinna ear cannal eardrum ossicles coclea Eustachian tube auditory nerve semicircular canals oval window

33. 1.5 Sense of Hearing Part of ear Structure Functions Pinna Made of cartilage and skins. Shape like a funnel Collects and directs sounds into the ear canal Ear canal A long tube, lined with hairs Directs sounds to the eardrum Eardrum A thin membrane Vibrates when sound waves hit it Ossicles Three small bones Amplify vibrations and transfer them to the oval window Oval window A small, thin membrane Transfers vibrations of the ossicles to the cochlea Cochlea A coiled tube, filled with fluid. Contains receptors Detects vibrations and converts then into nerve impluses Eustachian tube A tube that connects the middle ear to the throat Equalises air pressure on both sides of the eardrum, preventing it from damage Auditory nerve Nerve fibers that connect to the brain Cariies nerve impulses to the brain Semicircular canals Three semicircular canals situated at right angles to each other Detect position and movement of head to help us keep our balance

34. 1.5 Sense of Hearing How do we hear????

35. 1.5 Sense of Hearing Pinna get sound Auditory canal Eardrum vibrate Ossicles vibrate Oval window Liquid in cochlea vibrate Sound waves Auditory nerve

36. 1.8 Sound & Hearing Sound produced by vibrations of an objects . When sound is produced kinetic energy is changed to the sound energy. Sound can travel through solids , liquids and gases . Sound cannot travel through vacuum . Sound travels faster trough solids than liquids or gases because the particles in a solid are very close together.

37. 1.8 Sound & Hearing Sound can be absorbed by a soft surface such as soft board on the walls of a cinema hall. Soft and rough surfaces are good absorbers of sound. Sound can be reflected when sound hits hard and smooth surfaces like walls. A reflected sound is called an echo. A large tunnel and a cave are examples that can give out echoes.

38. 1.8 Sound & Hearing Defects of hearing and ways to correct them Hearing loss can be occur from wax blockage, a punctured eardrum, birth defects or ear infections. The damage is often temporary and can be treated medically or surgically.

39. 1.8 Sound & Hearing Defects of hearing and ways to correct them Other hearing loss can be caused by the processes of aging, bacterial infections, a severe blow to the side of the head, extended exposure to loud sound or a tumour in the inner ear. This damages cannot be treated medically but can be corrected using hearing aids.

40. 1.8 Sound & Hearing Limitations of hearing Our ears can only hear sounds which have a frequency of about 20 Hz to 20 000 Hz. Different people have different ranges of hearing. Some devices that are used to overcome the limitations of hearing such as earphones and stethoscopes.

41. 1.8 Sound & Hearing Stereophonic hearing Stereophonic hearing is hearing with both our ears. Stereophonic hearing helps us to determine the direction from which a sound comes.

42. 1.6 Sense of Sight

43. 1.6 Sense of Sight The eye is the sensory organ of sight and it is sensitive to light . Human beings have a pair of eyes situated in the socket of the skull. Each eye is surrounded by fatty tissues.

44. 1.6 Sense of Sight Cilialry body Conjuctiva

45. 1.6 Sense of Sight Model of a human eye

46. 1.6 Sense of Sight Model of a cow eye

47. 1.6 Sense of Sight Light enter the eye through the cornea and aqueous humour to the pupil and to the lens of the eye. The convex lens focusses the light rays onto the vitreous humous and the retina to produce a clear image. cornea aqueous humour pupil lens vitreous humous retina optic nerve

48. The Formation of Images How do we see????????? 1. Light rays travel from the object to eye 2. The light rays pass through the eye, they are refracted by some cornea, aqueous humour, lens and vitreous humour 3. An upside down image (flag) is formed on the retina 4. The photoreceptors on the retina send nerve impulses along the optic nerve to the brain 5. The brain interprets the impulses and allows us to see the object

49. 1.7 Light & Sight Light plays an important part in our life because without light we cannot see. The properties of light are: (a) its travels in straight lines. (b) its can be reflected. (pantul) (c) its can be refracted. (bias)

50. Properties of Light Light travels in a straight line Light can be reflected Light can be refracted Light can be dispersed

51. 1.7 Light & Sight Light travels in straight lines . This causes the formation of shadows and eclipses of the sun and the moon.

52. 1.7 Light & Sight Light can be reflected . The image in a plane mirror is due to the mirror reflecting light from the object to the observer. This is because the light bounces off the surface of an object. A smooth and shiny opaque surface reflects more light than a rough surface.

53. 1.7 Light & Sight The image in a plane mirror the angle of reflection = the angle of incidence

54. 1.7 Light & Sight regular surface irregular surface

55. 1.7 Light & Sight When light travels from one medium to another, its speed changes. This causes the light to bend or change its direction means the light is refracted .

56. 1.7 Light & Sight When light ray travels from a less dense medium (air) to a more dense medium (glass) the refracted ray bends towards the normal . mirror air ray normal

57. 1.7 Light & Sight When light ray travels from a more dense medium (glass) to a less dense medium (air) the refracted ray bends away from the normal . mirror air ray normal

58. 1.7 Light & Sight When light ray travels medium perpendicularly the light ray passes straight through the medium without being bent or refracted. mirror air ray normal air

59. 1.7 Light & Sight A stick which partly immersed in water to appear bent at the surface of the water.

61. What do you see? Do you know what MYOPIA is?! 1.7 Light & Sight

62. 1.7 Light & Sight Short­sightedness (myopia) Able to see near objects clearly but cannot see distant object. To correct this defect, the person has to wear concave lenses .

63. 1.7 Light & Sight

64. SHORT SIGHTEDNESS NORMAL VISSION SHORT SIGHTEDNESS 1.7 Light & Sight

65. 1.7 Light & Sight A distance object cannot be seen clearly because the image is focused in front of the retina. This is because the eye lens is too thick or the eyeball is too long. It is corrected by using a concave lens to diverge the rays of light on the retina.

66. NORMAL VISSION LONG SIGHTEDNESS Do you see the difference? Is this what we call HYPEROPIA?! 1.7 Light & Sight

67. 1.7 Light & Sight Long­sightedness (Hypermetropia) A long­sightedness person can see distant objects clearly but cannot see near object. To correct this defect, the person has to wear convex lenses .

68. 1.7 Light & Sight A near object cannot be seen clearly because the image is focused behind of the retina. This is because the eye lens is too thin or the eyeball is too short. It is corrected by using a convex lens to converge the rays of light on the retina.

69. 1.7 Light & Sight Astigmatism Astigmatism is a common vision defect caused by the irregular surface of the cornea. Things look blur to a person with astigmatism. This defect of vision can be corrected using cylindrical lenses.

70. 1.7 Light & Sight Now test your eyes for astigmatism by looking at the figure below. If one or more lines in the chart appears clearer and black but the others appear blurred, then you have astigmatism. astigmatism image normal image

71. 1.7 Light & Sight Can you see the craters on the moon ? Can you see microorganism in the air?

72. 1.7 Light & Sight Limitation of Sight Our sense or sight has its limitations. We cannot see objects that are very tiny, such as bacteria, viruses and atoms with our naked eye. We also cannot see the stars and planets that are very far from Earth. Examples of limitations of sight are: (a) optical illusions (b) blind-spot

73. 1.7 Light & Sight Optical illusions The image formed in the eye is accurate but the brains plays a trick and makes the image misleading.

74. 1.7 Light & Sight Optical illusions

75. 1.7 Light & Sight Blind-spot (scotoma) The blind spot is the point on the retina where the optical nerve leaves the eye. Close your left eye and stare at the cross mark in the diagram with your right eye. Now slowly move toward the diagram. Keep looking at the cross mark while you move. At a particular distance, the spot will disappear (it will reappear again if you move even closer). The spot disappears because it falls on the optic nerve head, the hole in the photoreceptor sheet.

76. 1.7 Light & Sight Stereoscopic and monocular vision Stereoscopic vision Monocular vision

78. 1.7 Light & Sight Devices to Overcome the Limitations of Sight Optical instruments Used to study small objects and specimens mounted on slides Used to study stars in the sky Used to observe distant objects Used by submarine to look out above the surface of the sea Used to scan and see the fetus of a pregnant mother

79. CAT Scan

80. MRI Scan

81. MRI Scan

83. 1.9 Stimuli & Responses in Plants

85. 1.9 Stimuli & Responses in Plants

87. 1.9 Stimuli & Responses in Plants

89. 1.9 Stimuli & Responses in Plants

91. 1.9 Stimuli & Responses in Plants