Tools and machinery. Use the tool 1. A machine is a device that can make us labor-saving or convenient. 2. Screwdriver, hammer and scissors are all simple mechanical structures, also called simple machinery. It is very convenient to take the screws out of the wood with a screwdriver and the nails out of the wood with a claw hammer. Different tools have different uses. Second, the science of leverage 1. A simple machine like a crowbar is called a lever. 2. There are three important positions on the lever: the position that supports the lever and enables it to rotate around the axis is called the fulcrum; The position of the force on the lever is called the force point; The position where the lever overcomes the resistance is called the resistance point. 3. When the distance from the resistance point to the fulcrum is less than the distance from the force point to the fulcrum, the lever saves effort; When the distance from the resistance point to the fulcrum is greater than the distance from the force point to the fulcrum, the lever is laborious; When the distance from the resistance point to the fulcrum is equal to the distance from the force point to the fulcrum, the lever is neither labor-saving nor laborious. There is a fulcrum on the lever ruler, and the distance from the fulcrum is marked on the left and right sides, which is a good tool for studying lever. 5. Hook the code in three different ways to keep the balance of the lever ruler. Draw your method in the picture below. Iii. Research on leverage tools 1. What is labor-saving is (iron sheet, claw hammer, vice, bottle opener), and what is laborious is (poker, tweezers). 2. Among the commonly used lever tools, claw hammer, vice and bottle opener are labor-saving levers; Firetongs, chopsticks and tweezers are laborious levers; Seesaw, balance and stap are all labor-saving and effortless levers. Some lever tools are designed with great effort because of the convenience (such as tweezers, fishing rods, etc.). ) .3. "Although the weight is small, it can press a thousand kilograms", which is the result of the steelyard using the lever principle (the hanging rope is the fulcrum, the weight is the force point, and the weight is the resistance point). The forearm bone on our body is like a lever, the elbow joint is the fulcrum, the place where we hold the object is the resistance point, and the biceps brachii of the upper arm is the stress point. Archimedes once said, "As long as I have a fulcrum in the universe, I can pry up the earth with a long stick." The stick here is equivalent to a lever. Fourth, the secret of the axle 1. Like a faucet, a machine with wheels and shafts fixed together is called a shaft. A screwdriver is a shaft tool. Its handle is a wheel and its spindle is a shaft. 2. important official saves power when driven by the force on the wheel; It takes a lot of effort to drive the wheel on the axle. 3. Axles can save labor. The bigger the wheel, the more energy will be saved when the wheel is used to drive the shaft to rotate. Therefore, the handle of a screwdriver is always thicker than the arbor. 4. The wrench is sleeved on the nut to form a shaft. At this time, the whole wrench is a wheel and the nut part is a shaft. 5. Axles in life: faucets, door locks, car steering wheels, wrenches, pulleys, etc. V. Crown block and moving pulley 1. Like the pulley at the top of the flagpole, it is fixed in one position, and the pulley that can't rotate is called the crown block; The crown block can change the direction of force, but it can't save effort. 2. The pulley that can move with the weight on the hook of tower crane is called moving pulley; Moving pulley can save labor, but it can't change the direction of force. 3. Moving pulley can save labor, but it can't change the direction of force. * Force is measured by dynamometer, and Newton is the unit of force, which is represented by the letter "n". Six, pulley block 1. The pulley block is composed of crown block and moving pulley. Using pulley block can not only save labor, but also change the direction of force. 2. The crown block and moving pulley are combined into the simplest pulley block. The more pulley blocks there are, the more labor is saved. 3. The crane uses a pulley block. 4.① Name: crown block ② Name: moving pulley ③ Name: pulley ④ Name: pulley function: function: function:? Changing the direction of force can save energy and energy, but it can not change the direction of force, and it can also change the direction of force. If you use them to lift 50 kilograms of objects with the same weight, the most labor-saving is (④), followed by (②, ③), and the least labor-saving is (①). Seven, the role of the slope 1. A simple machine like the wooden board on the carriage is called an inclined plane. 2. The inclined plane can save energy, the smaller the slope of the inclined plane, the more labor-saving, and the greater the slope, the less labor-saving. 3. There are many places where inclined planes are used in life, such as "S" type Panshan Highway, various slopes, various blades, threads, approach bridges of viaducts and so on. 4. The thread of the screw is the deformation of the inclined plane. Screws with the same thickness, the denser the thread, the easier it is to screw into the wood. 5. Research question: Does the slope gradient affect labor saving? My hypothesis: the inclination of the inclined plane has an influence on the amount of labor saving; The smaller the slope of the inclined plane, the more labor-saving it is. Conditions to be changed: the slope of the inclined plane (the height of the wood block) is unchanged: the same weight, the same board, the speed of lifting the weight; Experimental method: (1) Put a board on wood blocks with different heights to make several inclined planes with different slopes; (2) Hook a heavy object with a dynamometer, and lift the heavy object along inclined planes with different slopes at the same speed; (3) Record and compare the forces exerted on each inclined plane. 8. Simple machinery on bicycles 1. Bicycles use simple mechanical principles such as levers (such as buttons for brakes and bells), axles (such as handles and pedals) and inclined surfaces (such as screws). These simple machines play a labor-saving or convenient role. 2. The relationship between the rotation speed of the gear on the bicycle and the gear size is as follows: when the big gear drives the small gear to rotate, the small gear rotates faster than the big gear; When the pinion drives the big gear to rotate, the big gear rotates slower than the pinion. * Synthesis: Please connect the following items with the simple mechanical principles applied. Oblique shaft lever pulley screwdriver tweezers screw faucet crane second unit shape and structure 1. Bending strength 1. There are vertical "columns" and horizontal "beams" in buildings and bridges, which are easier to bend and break than columns, so it is necessary to improve the bending resistance of beams. 2. In order to improve the bending resistance of materials, we can increase the width, thickness or shape of materials. 3. With the increase of paper width, the bending strength will also increase; With the increase of paper thickness, the bending strength will increase greatly. 4. Research question: Is the width of paper related to the bending strength? Experimental materials: two stacks of books, three A4 sheets of paper and several washers. Experimental hypothesis: The wider the paper, the greater the bending strength. Experimental steps: ① Take two stacks of books as piers and put a piece of paper, which can bear several washers at most; (2) Put two pieces of paper, which can bear several washers at most; (3) Put three pieces of paper, which can bear several washers at most; ④ Compare the results and draw a conclusion. Constants to be controlled in the experiment: the width of paper; The constant quantities are: the height and width of the pier, the size of each piece of paper, the weight of each washer, and the degree to which the paper is crushed. In this experiment, we use the number of load-bearing washers to represent the bending capacity of paper beams. Shape and bending resistance 1. Bending sheet material into V-shape, L-shape, U-shape, T-shape or I-shape reduces the width of the material, but increases the thickness of the material, which can greatly enhance the bending capacity of the material. 2. Generally, the beam is placed vertically, because the beam is placed vertically, which reduces the width of the material, but increases the thickness and greatly enhances the bending capacity of the beam. 3. Why can the structure of corrugated board make soft paper hard? Because the middle structure of corrugated paper is W-shaped, although the width of the material is reduced, the bending resistance of the material is greatly enhanced by increasing the thickness. III. Arch strength 1. When the arch bears the weight, it can transfer the pressure downward and outward to the adjacent parts, and the various parts of the arch are more tightly squeezed and combined. When the arch is compressed, it will produce an outward force, and when it resists this force, the arch can bear a lot of weight. 2. The arch foot can keep the shape of the arch unchanged, and the arch can bear more weight. Fourth, ask for the memorial archway 1. The dome shape can be regarded as a combination of arches, with the advantage that the arches bear large pressure and do not produce outward thrust. A sphere can be regarded as an arch in all directions, which makes it stronger than any other shape. 3. The top and bottom of the plastic bottle are approximately dome-shaped, and the middle is cylindrical. The thickest and hardest is in the bottle mouth, and the thinnest and softest is in the bottle body. The structure of the human body is very delicate. The skull is almost spherical and can protect the brain well; Arched ribs guard the internal organs in the chest; People's foot bones form an arch, which can better bear the weight of the human body. 5. Arch in life: rib, arch, arch, arch window, arch bridge; Dome shape: turtle shell, shell; Sphere: eggshell, fruit, skull. 6. With the same amount of material, the hollow tube is much thicker than the solid rod, and the bending capacity in any direction is the same, that is, it is light in weight and high in strength. This principle applies to the tubular arm bones, leg bones, stems and steel pipes of plants. 5. Make a framework 1. A skeleton structure like an iron tower is called a frame structure. Triangular frames have the characteristics of stability. 2. Rectangular frames, cubical frames and diagonal bars are equivalent to triangles inside, which can play a reinforcing role. Six, build a tall tower 1. Frame structure can build a tall building, but the materials used are very few. Frame structure is based on triangle. 2. Structural characteristics of the frame tower: ① The upper part is small and the lower part is large, the upper part is light and the lower part is heavy, and the wind resistance is small. Seven. The shape and structure of the bridge 1. For an arch bridge with a bridge deck under the arch, the bridge deck can pull the arch foot to offset the outward thrust of the arch and reduce the burden on the pier. The bridge deck is also relatively low and flat, which is convenient for traffic. 2. The steel cable can bear huge tensile force, and the steel cable bridge built with it greatly increases the spanning capacity of the bridge. 3. Structure of cable bridge: It consists of steel cables, bridge towers and bridge decks. The steel cable is the main load-bearing component of the bridge, and the pylon is the main supporting component of the steel cable. The bridge tower was built high to reduce the tension of the steel cable. Eight, build a bridge with paper 1. What problems should be considered in designing bridges with paper: ① the characteristics of paper; (2) What are the characteristics of paper durability? ③ Choose the shape and structure. ④ What methods are used to enhance the bending resistance of paper? 2. The total length of Hangzhou Bay Bridge is 36 kilometers, ranking first among the bridges under construction and built in the world. It was officially opened to traffic on May 1 2008. 3. Indicators for evaluating bridge quality: ① Whether it is firm; (2) whether to save materials; 3 whether it is beautiful. The third unit energy I, electricity and magnetism 1. When there is current in the wire, magnetism will be generated around the wire. 2. 1820, Danish scientist Oster found in an experiment that the compass will deflect when the electrified wire is close to it. 3. If the circuit is short-circuited, the current will be strong and the battery will run out soon, so disconnect it as soon as possible. 4. When doing the experiment of electrified coil and compass, the coil should be placed vertically, and the compass should be as close to the center of the coil as possible, with the largest deflection angle. Second, electromagnet 1. A device consisting of a coil and an iron core like this is called an electromagnet. 2. Electromagnets have a north pole and a south pole. The north and south poles of electromagnet are related to the connection of battery and the winding direction of coil. When the connection between the anode and cathode of the battery changes, its magnetic pole will also change. When the winding direction of electromagnet coil changes, its magnetic pole will also change. 3. Similarities between electromagnets and magnets: both are magnetic, and both have north and south poles. The difference between electromagnet and magnet: (1) A magnet is a magnet, and an electromagnet consists of a coil and an iron core. (2) Electromagnets are magnetic only when energized. (3) The north and south poles of the magnet will not change, but the north and south poles of the electromagnet can change. Iii. Magnetic force of electromagnet (1) 1. The magnetic force of electromagnet can be changed, which is related to the number of batteries, the number of coils and the size of iron core. 2. Study on the relationship between electromagnet magnetic force and coil turns. Is there a relationship between the magnetic force of electromagnet and the number of turns of coil? Our hypothesis is that the number of coils is large and the magnetic force is large; The number of coils is small and the magnetic force is small. Test factors (changing conditions) how to change the number of coil turns 1. Coil 20 turns 2. Coil 40 turns 3. These conditions should be kept unchanged in the experiment of 60 turns of coil. Experimental conclusion: the magnetic force of electromagnet is related to the number of coil turns, and the more coil turns, the greater the magnetic force; The number of coils is small and the magnetic force is small. Fourth, the magnetic force of electromagnet (2) 1. Study on the relationship between the magnetic force of electromagnet and the number of battery sections? Our hypothesis is that the battery has many sections and large magnetic force; The number of battery sections is small and the magnetic force is small. Test factors (changing conditions) how to change the number of battery sections 1. Battery 1 section 2. Battery 2, Section 3. Some experiments of battery 3 should keep these conditions unchanged. Experimental conclusion: the magnetic force of electromagnet is related to the number of battery sections, and the more battery sections, the greater the magnetic force; The number of battery sections is small and the magnetic force is small. 2. In scientific inquiry, the order of inquiry is: 1. Question 2. Establish a hypothesis. Design the experimental scheme. Collect facts and evidence. Test hypothesis. AC 5。 Magic small motor 1. The function of the commutator is to switch on the current and change the direction of the current. When the small motor rotates, the brush contacts the three metal rings of the commutator in turn, and the direction of current passing through the rotor coil will be. 2. Small motor includes shell, rotor and back cover. There are a pair of permanent magnets in the shell, an iron core, a coil and a commutator on the rotor, and a brush on the back cover. 3. A motor is a machine that uses electricity to generate electricity. Although the size is very different and the structure is different, the basic principle of motor work is the same: electricity produces magnetism, and the interaction of magnetism rotates. 6. Electricity and energy 1. Energy has different forms, such as electric energy, thermal energy, light energy and sound energy. Moving objects also have energy, called kinetic energy. Energy is also stored in fuel, food and chemicals, which is called chemical energy. 2. Everything needs energy to work. Without energy, there would be no movement and change in nature, and there would be no life. Energy input is in the form of electrical output energy. Rice cooker, electric fan, kinetic energy, TV light energy and acoustic light energy, electric furnace heat energy. All electrical appliances are electric energy converters, which can convert the input electric energy into other forms of energy. Seven. Where does the electricity come from 1. Various batteries: dry batteries (ordinary batteries, button cell)-chemical energy is converted into electrical energy; Solar cell-solar energy is converted into electric energy, which cannot be stored and can only be used immediately; Battery-converts chemical energy into electrical energy when discharging, and converts electrical energy into chemical energy when charging. When the motor is used to generate electricity, it should be called a generator. 3. Sources of electric energy and sources of converted electric energy, forms of converted energy output, ordinary batteries, chemical energy, electric energy, photovoltaic energy, hydropower stations, kinetic energy, thermal power plants, nuclear energy, energy and the sun, 1. Coal is transformed from ancient plants. After the ancient plants died, they were covered with silt, isolated from the air by settlement, and buried deep underground by the changes of the crust. They have been subjected to high temperature and pressure for a long time and gradually turned into coal. 2. Oil and natural gas were formed by long-term complex changes of a large number of lower organisms hundreds of millions of years ago. The energy possessed by coal, oil and natural gas is solar energy stored for hundreds of millions of years. 4. New energy: direct utilization of geothermal energy, wind energy, tidal energy, nuclear energy and solar energy. 5. Coal, oil and natural gas are non-renewable energy sources. If we use a little, we will use less. We are running out of energy. Unit 4, Biodiversity 1. Campus biological search 1. Up to now, more than 2 million species have been found and classified, and it is estimated that there should be 2-4.5 million existing species on the earth. Scientists often investigate the species and distribution of animals and plants in an area. Sub-regional observation and research is a common method in scientific research. 3. Pay attention to the investigation of plants and animals on campus: don't pick plants and hurt animals; Hidden animals can be inferred from footprints, feces, hair and other traces, and birds that often fly should also be recorded; Looking for small animals living underground, bring a shovel, preferably a magnifying glass; Unknown animals and plants can be recorded by painting, taking pictures and other appropriate methods. Campus biological distribution map 1. There are many kinds of animals and plants on campus, and the living environment is also different. 2. The rare plants in China are Davidia involucrata, Ginseng, Metasequoia glyptostroboides, Ginkgo biloba, camellia, etc. Rare animals in China include giant panda, Tibetan antelope, Chinese alligator, baiji, Asian elephant and golden monkey. Third, all kinds of plants 1. Classification can help us to better identify and study animals and plants. According to different standards, plants can be divided into different kinds. For example, according to the characteristics of stems, plants can be divided into woody plants (such as peach trees and camphor trees) and herbs (such as green bristlegrass and rice); Plants are divided into aquatic plants (such as duckweed) and terrestrial plants (such as cedar) according to their living environment. Scientists classify plants mainly according to their characteristics. They divide plants into two categories according to whether they have flowers or not: flowering plants and non-flowering plants. 4. In the plant kingdom, more than 300,000 species have been found, of which flowering plants account for more than half. Among non-flowering plants, ferns, algae and mosses, like flowering plants, make their own food through photosynthesis. 6. Non-flowering plants include ferns (such as bracken), algae (such as laver) and bryophytes (such as cucurbitaceae). 7. Flowering plants are: peach trees, rape flowers, impatiens, roses, Ceratophyllum, etc. 4. A wide variety of animals 1. Scientists divide animals into vertebrates and invertebrates. Animals with spines are called vertebrates, and animals without spines are called invertebrates. 2. Like ants, locusts and bees, animals with three feet are insects; Like goldfish and carp, they live in water all their lives, and the animal that breathes through gills is fish; Animals with feathers are birds; Give birth to small animals directly and feed them with milk. They are mammals. Reptiles: There are scales or armor on the body surface, and the abdomen clings together when crawling. Amphibians: when they were young, they lived in water and breathed through their gills; When I grow up, I live on land and breathe with my lungs. 3. The body structure and life activity characteristics of animals are important criteria for scientists to classify animals. 4. In the animal kingdom, more than10.5 million species have been found, which is the highest in the life world. Insects are the largest species in the animal kingdom, with more than 6,543,800 species known, accounting for about 80%. 5. Vertebrates are a kind of animals with complex structures, which can be divided into fish, amphibians, reptiles, birds and mammals. Vertebrates: mammals: bats, sheep, rabbits, pigs, whales and seals; Birds: chicken, duck, goose, eagle, goose, owl; Reptiles: geckos, snakes, crocodiles, turtles, lizards, turtles; Amphibians: toad, salamander, python; Fish: hippocampus, crucian carp, etc. We can't find two people who look exactly alike. Sixth, the original text is interrelated 1. The leaves of plants have photosynthesis and transpiration. Cactus lives in a desert that lacks water. In order to reduce the evaporation of water, the leaves degenerate into spines, and the stems are green, plump and juicy, which bear the functions of photosynthesis and water storage. Pine trees have a wide range of life, and needles can reduce water evaporation and help maintain body temperature; Bananas live in tropical areas rich in water, and their leaves are wide, which is more conducive to evaporating water in the body and regulating the temperature of plants. The different morphological structures of plants are the result of their long-term adaptation to the living environment. 2. Animals living in different environments also have obviously different morphological structures. 3. Duckweed is a floating plant among aquatic plants, with a degenerated root system and only one fine root; Grass and corn live on land. Roots not only fix plants in the soil, but also absorb water from the soil for plants to survive, so they all have huge roots. 4. The morphological structure of organisms is related to their living environment and habits. Cats have meat pads on their feet, which make a small noise when running on the ground and are not easy to be found by predators; Hook-shaped bird claws are easy to grasp the trunk, which is suitable for living in the forest and is conducive to catching small animals; Ducks have webbed feet, which can be used for paddling and are suitable for living in water. Xanthium sibiricum seeds have thorns, which are easy to be carried and spread by animals when living on land; Lotus seeds have a hard shell and can drift in the water; Dandelion seeds are hairy and easy to drift with the wind. Animal name Living environment Physical characteristics Function Goldfish swims in the water. Breathing fins in the water are spindle-shaped to reduce the resistance of water to it. Pigeons' air feathers keep warm, and the waterproof skeleton is hollow and light, making it easy to fly. 7. Who chose them 1? In the wild, green frogs are preserved because of their good camouflage, and frogs of other colors are eaten by predators because they are too conspicuous. 2. Biologists found a very interesting phenomenon when comparing biological individuals in different places, that is, the colder the same creature, the bigger the individual, and the closer the body is to a circle; And the exposed nose, ears, legs and other organs are relatively small. 3. With the change of environment, the morphological structure of animals also changes. All kinds of creatures are caused by all kinds of environments. 4. Natural selection has changed the living things, but artificial selection is also enriching the species diversity. In the experiment, we found that the water temperature in a large spherical flask dropped slowly, while that in a slender glass bottle dropped rapidly. In nature, the shape of large and round animals will gradually get cold. The significance of biodiversity 1. The earth is our beautiful home, and all kinds of creatures play different roles in this home. They depend on each other, interact and influence each other. 2. Biodiversity is the foundation of human survival and development. Every living thing is closely related to human life. Human beings cannot live without biodiversity. All kinds of creatures have different values to us. Some have appreciation value and scientific value, some have economic value and some have medicinal value. Just as human life is inseparable from biodiversity, every living thing needs to live in an environment with biodiversity. For example, flowers need insects to help pollinate their offspring; Xanthium sibiricum spreads seeds through animals; Animal excreta can be used as food for plants; Grasshoppers need to feed on plants such as rice. 6. To protect biodiversity, we should start with protecting biodiversity in our hometown. 7. Human beings are members of the biological family, so we should treat every member of the family equally. 8. Plants are indispensable to human life: they provide food for human beings; For people to appreciate; As a medicinal material, it is provided to humans; Humans can use plants to make daily necessities and school supplies; Can purify the air; Provide food for animals. Database: 1. The basic living conditions of living things include sunshine, air, water and region. 2. The Treaty on Biological Diversity entered into force in 1993. May 22nd every year is called International Biodiversity Day. 4. More than 65,438+080 countries in the world have become parties to the Convention on Biological Diversity.
Trolley group primary school
Like when I was in primary school, you didn't review at the end, but it's okay!