machinesl
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The document discusses machines and structures as part of a 5th grade curriculum. It defines machines as devices that convert one type of energy into another, and provides examples of simple machines like wheels, pulleys, inclined planes, and levers that modify the application of forces. It also describes the typical components of machines like motors, electrical circuits, sensors, and indicators. Machines are classified based on their energy source such as human, water, fuel, or electricity. Overall, the document provides a basic overview of what machines are and some of their common components and uses.
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- 1. CEIP Gin辿s Morata Almer鱈a Equipo Biling端e Andr辿s Egea 5th GRADE MINIMUM CONTENTS UNIT 5: MACHINES AND STRUCTURES 鐃 Machines Machines are devices which use the action of a force to convert one type of energy into another. For example, a bicycle is a machine which transforms human energy into mechanical energy. Machines save us time and physical effort鐃 鐃Types of machines Some machines, such as pulleys, are very simple because they have very few components. Other machines, such as computers, are complex because they have many components. Machines can be classified depending on the energy source. There are machines which work with: Human energy, such as a bicycle or a hammer Water or wind, such as a watermill or a windmill Fuel, such as a car or a gas stove Electricity, such as a washing machine or a mobile phone * Machines which produce movement Many machines produce movement, such as escalators, cars or food blenders. These machines have a motor or an engine. The motor converts fuel or electrical energy into movement. * Thermal machines Thermal machines, such as heaters and air conditioners, produce heat or cold. * Information-processing machines Information-processing machines are used for communication and calculations. For example, we can communicate with others using mobile phones, and we can make calculations on computers. CEIP Gin辿sM orata 鐃緒申
- 2. CEIP Gin辿s Morata Almer鱈a Equipo Biling端e Andr辿s Egea 鐃緒申Simple machines There are four types of simple machines: the wheel, the pulley, the inclined plane and the lever. These machines modify the action of forces. The wheel The wheel is a simple machine, but it can be used as a component of complex machines. It consists of a round part which turns on an axle. Wheels are used on the majority of vehicles which move on land. Wheels are useful because they reduce friction with the ground. Therefore, they make it easier to move objects along the ground. The pulley The pulley is a kind of wheel. It has two raised edges so a rope can run around the wheel without falling off. A pulley is used to lift heavy objects. A pulley changes the direction needed to apply force. Look at the picture. Instead of pulling directly upwards (A), the pulley enables you to pull downwards and lift the object more easily (B). The inclined plane An inclined plane is a slope or a ramp. It makes it easier to move heavy objects. It requires less force than if you raise an object vertically. Instead of lifting the object straight up, you can push it a greater distance using less force. The picture shows that the force required to lift an object with a pulley is greater than the force required to move the object up an inclined plane. The smaller the angle between the plane and the ground, the smaller the force required, and the longer the distance. The lever A lever is basically a long stick that you push or pull against a fulcrum or pivot point to make something move. A lever makes it easier to move heavy objects. Look at the picture. When you apply force to a lever, the long end of the lever moves a greater distance than the short end. The short end of the lever applies a much greater force on the object than the force you apply to the long end. Types of levers There are three types of levers: 鐃緒申 First-class levers. The fulcrum is between the load and the energy moving the force. Crowbars, pliers and scissors are examples of first-class levers (A). 鐃緒申 Second-class levers. The fulcrum is at one end and the load is between the fulcrum and the force. Guillotines, wheelbarrows and nutcrackers are examples of second-class levers (B). 鐃緒申 Third-class levers. The force is applied between the fulcrum and the load. Your arm and some types of cranes are examples of third-class levers. In your arm, the fulcrum is your elbow. The force is applied by your muscle (C). CEIP Gin辿sM orata 鐃緒申
- 3. CEIP Gin辿s Morata Almer鱈a Equipo Biling端e Andr辿s Egea 鐃Inside a machine The structure and housing The structure of a machine, also called the chassis or frame, is the skeleton of the machine. The other components are built on or around the structure. The housing or cover protects the machine. The housing usually contains elements that help us control the machine. For example, the buttons on a video game console controller or the switch on a blender. The motor and operating parts Automatic machines that produce movement have a motor or engine. There are two types: Combustion engines are used in most vehicles, and in machines such as chainsaws and steamrollers. Electric motors are used in many automatic machines, from small home appliances to electric locomotives. Operating parts and mechanisms are used to transmit the movement of the motor to other parts of the machine. Electrical circuits and electronic circuits We find circuits in machines that function with electrical energy. Electrical circuits and electronic circuits direct the energy that is transmitted to the motor and other parts. Electronic circuits are extremely small. A memory chip is an example of a small electronic circuit that can contain millions of components. Machines with electrical circuits or electronic circuits can only work when they are connected to an electrical grid or when they have batteries. Sensors Sensors enable a machine to receive information from the outside or inside of the machine. A temperature sensor can turn on a radiator automatically when the temperature goes down outside. A light sensor stops lift doors from closing when someone is trying to get in or out. This can prevent injuries. An infrared sensor from a television enables you to control it with a remote. An antenna makes it possible for a radio to receive information through the air. Indicators and screens Indicators and screens give us information about how the machine is functioning. For example, car indicators show the speed or the temperature of the engine. The indicator on a lift shows what floor it is on. Some machines, such as computers and mobile phones, use digital screens. These are more sophisticated than indicators and can display photographs and videos. CEIP Gin辿sM orata 鐃緒申
- 4. CEIP Gin辿s Morata Almer鱈a Equipo Biling端e Andr辿s Egea UNIT 5: MACHINES ACTIVITIES 1.- Complete the text about the uses of machines. Machines are very for human beings. Most importantly, they make doing things easier. They enable us to exert less to complete a task, such as lifting a heavy object. However, machines are also important in other ways. Firstly, machines help humans to complete tasks more quickly. Secondly, they can do complicated tasks very easily. For example, electronic circuits must be very precise, some factories use machines to make them with . Thirdly, we use machines when a task is very , like exploring the sea floor. Fourthly, machines enable us to one kind of energy into another. For example, a solar-powered changes light energy into electrical energy. 2.- Fill in the blanks Machines can be classified depending on the energy source. There are machines which work with: , such as a washing machine or a mobile phone , such as a watermill or a windmill , such as a bicycle or a hammer , such as a car or a gas stove 3.- Look at three machines. What does each one do for us? Name them. CEIP Gin辿sM orata 鐃緒申