Developments and their Applications and effects in everyday life
Science is a systematic enterprise that builds and organizes knowledge in the form of explanations and predictions about nature and the universe. It is the study of nature and behavior of the physical and natural world through the scientific method. It is also defined as the observation, identification, description, experimental, investigation, and theoretical explanation of natural phenomena. Whereas, Technology is the collection of techniques and processes used in the production of goods or services or the accomplishment of objectives such as scientific investigation. It includes methods, systems, and devices which are the result of scientific knowledge being used for practical purposes. The world around us behaves according to scientific laws. Scientists have discovered many of these laws, and are making new discoveries all the time. We develop technology using our understanding of science and the forces, such as magnetism, gravity and electricity, which shape our lives. Whenever we turn on a light, log on to internet or speak with our friends or relatives on a mobile phone, it has all been made possible by science.
The World Around us
Everything, from water or air to a whale or a mobile phone, is made of tiny particles called atoms. There are over 100 different kinds of atoms. There are over 100 different kinds of atoms, which are in turn made of smaller parts called subatomic particles. Two or more atoms join together to make a molecule. The things around us are solids, liquids or gases depending on the arrangement of the atoms and molecules inside them.
Forces and movement
Things move only when a force is applied to them. Forces are pushes or pulls in a particular direction. A flag blows when the wind pushes it. A door opens when you pull it. Animals move when their feet push against the ground, their wings push against the air or their fins push against the water around them. Forces always work in pairs. They push and pull in opposite directions. When pairs of forces are equal they are said to be balanced. Tug of war teams remains still when each pulls with the same strength. A team falls when one side is stronger and the forces are unbalanced. Forces are also balanced when things move at one speed in the same direction. Things slow down and stop because of an opposing force. One of these forces is friction. Friction happens when tiny bumps on two surfaces rub against each other. Rough surfaces, such as concrete, create more friction than smooth surfaces, such as glass. People use high-friction materials like rubber on shoe soles to stop people slipping when they walk.
Light and Dark
The earth’s biggest source of light is the sun. Heat and light energy created by the sun travels through space in straight lines called rays at almost 300,000 kilometres per second. The Earth spins right around once a day, changing which parts of globe get sunlight. This creates day & night. Other things that radiate, or give off, light include electric light bulbs, candles and television series. Shadows happen in places where an object stops light from getting through. Materials that light shines through fully are said to be transparent. Translucent materials let only a little light through. Opaque materials do not let any light through at all. The shape of a shadow depends on the shape of the object blocking the light. If an object is moved closer to light source, its shadow gets bigger because it blocks more light rays. All surfaces reflect light but, if they are bumpy, the light rays are reflected in all directions.Mirrors are made from very smooth surfaces that reflect the rays back in the same pattern as they hit it, creating a clear image of object. Words reflected in a mirror appear back to front, as if they were facing away from us and we were looking through the page.
There are seven colours in a rainbow and they always come in the same order: red, orange, yellow, green, blue, indigo and violet. Light from the sun may look white, but it is actually a combination of many colours. When tiny drops of water in the air split white sunlight into its different colours, we see a rainbow. Gases and dust in the atmosphere make the different colours in sunlight scatter so the sky changes colour. By day, the atmosphere scatters blue light towards earth so the sky looks blue. At sunset, when sunlight has more atmospheres to travel through before it reaches the surface of the earth, red light is scattered so the sky looks orangey red. People print colour images and words on paper using just four coloured inks: yellow, cyan (blue), magenta (red) and black. Paper is printed with tiny dots of different amounts of each ink. Our brain cannot distinguish that dots we see separately, but instead, blends them together to make different blocks of different colours
Sound is a disturbance of the air made when something, such as a string, vibrates, or moves back and forwards quickly. The vibration makes the air moves in waves. Our ears detect the moving air and our brains distinguish it as a sound. High sounds, such as notes from a flute, are made by short sound waves. Low sounds, such as a tuba’s notes, are made by long ones. Sound vibrations travel way from the thing that makes them. The vibrations spread out in all directions like the ripples in a pond after you throw in pebble. The wider the vibrations spread, the smaller they become and the quieter the sound. Big vibrations, on the other hand, makes lots of energy that pushes lots of air, creating loud sounds. Sounds are measured in units called decibels. The quietest sounds, such as a leaf falling, are around 0-10 decibels. The loudest sounds, such as a rocket launch, are just less than 200 decibels. Noises above 90 decibels are dangerous to listen to because the strong waves of air can damage the sensitive insides of your ears. Echoes are the repeated noise we hear when sound waves bounce off solid objects, such as a cliff or the inside of a tunnel. If the object is close by, the waves reflect so quickly we cannot hear the echo as a separate sound. Bats use echoes to get around in the dark. They make squeaks and listen to the echoes to work out how far away things are and how big they are.
Electricity is a type of energy formed from tiny particles inside atoms called electrons. These electrons can move from one atom to another and this movement is electrical energy. Electricity powers many machines, from torches and mobile phones to television and computers. It moves, or flows, into machines through materials called conductors, which include metal wires. Mains electricity is produced in power stations by machines called generators. Fuel, such as coal, is burned in the power station to turn water into steam. The steam turns a turbine (a set of large circular blades), which rotates magnets inside the generator, producing electricity. The electricity flows through wires to sockets in our homes. Batteries are useful for supplying small amounts of power to portable or mobile machines without the need to plug into wall sockets. Batteries are stores of chemicals that create a flow of electrical energy. Some batteries run out when the chemicals are used up, but rechargeable batteries regain their stored electrical when plugged into a socket. Switches work by controlling the flow, or current, of electricity through machines.Electricity can only flow through a circuit, which is a continues loop of wire. A switch is rather a gate that can open or close to break or complete the circuit.
It includes computer, digital cameras, MP3 players and mobiles. These records, store, send and process electronic signals as digital information. Digital means that the electrical signals are either ‘on’, ‘1’, or ‘off’, ‘0’. The 1s and 0s form a code that can represent any type of information. Microchips work using tiny electrical circuits. The circuits are built on paper-thin chips of silicon, a material that is very good at conducting electricity (allowing electricity to pass through it). A single microchip a contain thousands of circuits, allowing it to process lots of digital information. Microchips mean that computers and other digital devices can be small and light.