五年级下册的科学概念复习资料（The concept of scientific review of the fifth grade of 2）.doc

五年级下册的科学概念复习资料（The concept of scientific review of the fifth grade of 2） The concept of scientific review of the fifth grade of 2 Class name: no.: 1, put a stationery box on the hand, will feel that the stationery box opponent has a downward pressure, this force is gravity. All bodies have a downward force, and this force is gravity. 2, in the north, near the north pole, the rising sun will not fall day (day) call; only the night without daytime (night) that day. 3, rose flowers and the animals around them, (plants) and underground (microorganisms) together form a community. A variety of organisms in a community (Biology) and (non biological) interrelated and interacting, a unified whole. We call them (ecosystems). 4. Food links between organisms, such as chains, are known as food chains. Depending on the food source of different organisms in the food chain, people call themselves producers (food producers), and they call food made by others (consumers). 5, the rubber band is stretched when the force generated by the elastic _ called _. The longer the elastic pull, the greater the elasticity. 6. Animals that feed on plants are called (herbivorous animals); animals called animals are called carnivores; and two kinds of food are called animals (omnivorous animals). 7, ancient China divided into one day and night (12) (Shi Chen). Every hour is the present two hours. When is 23 PM to 1 am. 8. Because of friction, the motion of an object is subjected to a force that obstructs motion. This force is called frictional force. The magnitude of friction is related to the degree of smoothness of the contact surface, the mode of motion (rolling or sliding), the weight of the object (the pressure on the ground) and so on. Examples of increased friction include shoe soles, snow chains, chains on automobile tires, and so on. Examples of friction reduction include lubrication of axles (Hua Bingxie). The friction force is divided into (rolling friction) and (sliding friction). 9, it