8 CONTENTS 



Exercise Page 



29. Sulphur . 52 



30. Iron , 53 



31. Oxygen 55 



32. Hydrogen 57 



33. Nitrogen 59 



34. Acids and Bases 60 



35. Salts and Neutralization 61 



36. A Simple Electric Cell 62 



37. Composition of Water (Demonstration) .... 63 



38. Composition of Air 64 



39. Does Air Exert Pressure? (Demonstration) . 66 



40. Barometer (Demonstration) 67 



41. Siphon 68 



42. Convection 69 



43. Moisture in the Atmosphere Condensation. 70 



44. Study of the Weather Map 71 



45. Water Capacity of Soils 75 



&. Soil Solutions , 76 



47. Gross Structure of Leaves 77 



48. Chloroplasts 78 



49. Making of Food for Plants 79 



50. Making of Food for Plants, continued 80 



51. By-Products in Food Making 80 



52. Transpiration 81 



53. Rate of Transpiration 82 



54. Is Air Necessary? 83 



55. Exchange of Gases in Respiration 84 



56. Roots 85 



57. Roots as Organs of Absorption 86 



58. External Structure of Stems 87 



59. Internal Structure of Stems 88 



60. Functions of Stems 89 



61. A Typical Flower 90 



