Lesson Space Travel 10 Let Us Learn About r space and spacecrafts. u astronauts, space suits and space stations. a the routine followed by astronauts in space. h how to become an astronaut. Think On TV, Samarth saw a rocket being fired up in the sky. His father told him that it is a space mission. He wondered what a space mission is. Do you know? Remembering We know that the Earth has a layer of air around it: the atmosphere. Have you ever wondered about what is beyond the sky? Have you wondered about space beyond the Earth’s atmosphere? Beyond the atmosphere, there is an open space where there is no air. All the heavenly bodies we see in the sky are present in this space. To learn more about them, we have to travel to space. How can we travel to space and to these heavenly bodies? First, we have to travel through the Earth’s atmosphere and then through the open space beyond it. 181010045-Alpine-G5-Textbook-Science-FY.pdf 51 47 03-Feb-18 2:41:38 PM
We use aircrafts such as planes to travel to faraway places. Can we use these aircrafts to fly into space? We cannot. Let us see why. We have learnt that the gravity of the Earth pulls everything towards it. So, all the things that we throw up fall back to the Earth. Due to this, the aircrafts cannot fly straight up, cross the atmosphere and enter the space. So, we need high-speed rockets to throw these aircrafts out of Earth’s gravity pull. If a rocket steers through the atmosphere carrying a spacecraft, the air will rub against its walls. This will make the aircraft heat up and catch fire. So, we need special vehicles which can travel at high speeds without catching fire. These special vehicles are called spacecrafts. A spacecraft can either carry human beings or an artificial satellite. rocket spacecraft Understanding The spacecraft is very different from an aircraft. So, the pilots who fly planes cannot fly them. Special pilots called astronauts fly spacecrafts. Have you seen any pictures of astronauts? Indian astronauts Rakesh Sharma Sunita Williams Kalpana Chawla 48 03-Feb-18 2:41:38 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 52
Look at the pictures of the astronauts. They wear special suits. Do you spacesuit know why? Space has no air to breathe. So, we will need oxygen supply. Moreover, in space, the sunlight will be very sharp and can cause sunburn. So we need to wear spacesuits, that help us to breathe and protect us from the harmful sunlight. The way we have airports for aircrafts to land and take off, there are space stations for spacecrafts. Currently, the International Space Station (ISS) is the largest space station in space. It is an artificial satellite orbiting the Earth. It is made in such a way that it is suitable for living in space. The people who travel into the space alight at the space station and stay there to find out more about space. the International Space Station (ISS) Application What do the astronauts do in space? What do they eat? How do they sleep? Let us find out. Astronauts have to rely on the food they carry with them. These space food items are similar to those eaten every day on the Earth. They include frozen vegetables and desserts, refrigerated food, fruits and dairy products. The menu on the ISS includes more than 100 items. Astronauts choose their daily menus long before they fly into space. There are three meals per day. Snacks can be eaten at any time. Salt and pepper are available only in a liquid form. Drinks range from coffee, tea to fruit punches. At least two hours of a day are spent exercising. This is essential to keep fit and healthy. Astronauts spend some time on spacewalks too. Space Travel 49 181010045-Alpine-G5-Textbook-Science-FY.pdf 53 03-Feb-18 2:41:38 PM
space food eating in space Astronauts carry out some experiments and research in space. For example, the experiment to find out what will happen to the growth of plants when there is no gravity. Sleeping is a little different in space. There is no up or down. Astronauts can attach their sleeping bags to a wall or a ceiling. They can sleep anywhere as long as they do not float around and bump into something. spacewalk experiments carried out sleeping in space in space Why do astronauts travel to space and other heavenly bodies? We get to know more about the changes in the Earth’s atmosphere when we look at it from space. Space travel can help us to discover new worlds. We travel to other heavenly bodies to find whether there is life on them. Have you watched any movies that show space travel and the living things which live on other planets (aliens)? view of the Earth from space space and aliens as shown in movies 50 03-Feb-18 2:41:38 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 54
Amazing Facts A project named ‘Mars One’ aims to set up human colonies on the planet Mars. Mars One will begin to send one person at a time from the year 2024. Three Indians – a man and two women, have been shortlisted for the next round of selection among top 100 people! Indians shortlisted for Mars One design of human colonies for the next round on planet Mars Higher Order Thinking Skills (H.O.T.S.) We have learnt that travelling to space is different from any other travel. If you want to be one of the few people to see the Earth from space and float in a spacecraft, how do you go about it? It takes many years of study and work. To be an astronaut, we have to study and get a degree in engineering, science or mathematics. After this, we have to undergo training on flying the spacecraft, lifestyle in space and so on. We must be healthy since astronaut training can be very tiring. Astronauts from different countries may share a astronaut training mission to space. So you should be good at a common language of communication like English. Are you still interested? If so, maybe someday, you can become one of the men and women who orbit the Earth in a spacecraft, walk in space or visit Mars! Space Travel 51 181010045-Alpine-G5-Textbook-Science-FY.pdf 55 03-Feb-18 2:41:38 PM
Lesson Wildfire 11 Let Us Learn About R natural disasters – wildfires. u the causes of wildfires. a the effects of wildfires. h avoiding human-made wildfires. Think Samarth was sharing his forest visit story with his friends. Then one of his friends said that on the previous day, he had seen a forest fire on TV. He also said that a lot of people died, when the fire spread to the houses of the people who lived nearby. Sherin, another friend of Samarth, said that she had seen some places getting flooded with water. Samarth wondered how forests caught fire or land got covered with water. Do you know how these disasters happen? Remembering Nature can become harmful at times. Sometimes the ground shakes or heavy rains flood the lands. Some other times, strong winds blow off everything in their way. In some places, a hot boiling liquid flows out of the Earth (lava) burning everything. Fire may break out in forest areas. All these can kill humans, animals and plants and can destroy houses, roads and so on. They are disasters caused by nature. 52 181010045-Alpine-G5-Textbook-Science-FY.pdf 56 03-Feb-18 2:41:38 PM
Let us learn about one of the natural disasters – wildfires. We will learn about some other natural disasters in the upcoming lessons. Wildfires are the fires which break out in the forests, grasslands and so on. In India, wildfires are very frequent. Around 20,000 wildfires wildfire occur in India every year. In the state of Uttarakhand, around 1600 wildfires broke out in 2016. Wildfires are common across the world. Understanding Now you know what a wildfire is. Do you know how it is caused? Fuel, oxygen and heat source are the three things that need to be present for a wildfire to happen. Firefighters call it a fire triangle. The dry leaves, branches and grass become the fuel. The heat of the Sun or lightning becomes the heat source. Oxygen is present in the air. Due to the extreme heat of the Sun or lightning, dry patches of grass or fire triangle leaves may catch fire. The fire may then slowly spread to nearby areas. Sparks can also be caused when dry branches rub against each other due to the wind. Sometimes wildfires are also caused by careless activities of humans. For example, people throw burning things like cigarette sticks near the roadsides or they may not put off their camp fires before they leave. In some places, when people burn their fields, the fire may spread to nearby forest areas. campfire burning straws in the fire may spread from a fields burning cigarette stick Application If a forest catches fire, along with all the forest products, wildlife will also be destroyed. Wildfire 53 181010045-Alpine-G5-Textbook-Science-FY.pdf 57 03-Feb-18 2:41:38 PM
Also, the people who live in the forest will become homeless, and they will have nothing to eat. This is a great loss. The smoke that comes out of the fire will cause air pollution. This results in breathing problems for the people who live nearby. But the fires are not always bad. The fires that break out in nature have some good effects too. In the forest areas with less rainfall, the leaves shed from the trees pile up on the ground. They do not decay as there is little moisture. Forest fires help to burn the thick layers of dried leaves and branches. When they burn, they form ash. Ash is rich in nutrients. This mixes with the soil and makes it more suitable for plant growth. So during the next rain, new plants can grow better. Uncontrolled wildfires can spread and cause a lot of damage. So, we control wildfires in many ways. We use water to control small fires. But in some places, this may not be possible. Then, helicopters are used to spray carbon dioxide, which can put out the fire. When a wildfire breaks out in a forest controlling wildfire or grassland close to where we live, we have to vacate our houses. We have to move to safer places till the fire settles down. Amazing Facts Wildfires occur on every continent except Antarctica as there are no forests in Antarctica! Higher Order Thinking Skills (H.O.T.S.) About nine out of ten wildfires break out due to human activities. Frequent and widespread wildfires are harmful to all living things. How can we ensure that our activities are not causing any wildfire? 1) No burning material should be thrown away. We should put out the fire. 2) After lighting campfire, we should put it out completely before we leave the place. 3) While burning waste materials in fields, we should make sure that the fire does not spread to nearby areas. 54 03-Feb-18 2:41:38 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 58
Lesson Cyclones and Floods 12 Let Us Learn About R cyclones. u how cyclones may cause floods. a support given to cyclone-affected people. H preparing in advance for cyclones. Think Saif was watching TV when his father said that he needed to watch the news channel, as a cyclone alert was given by a government agency. On the news channel, they were talking about strong winds and heavy rains and showing something on a map. Saif wondered what a cyclone was. Why did the government give cyclone alerts? Remembering Let us do an activity. Take a glass of water. Add a few small sized seeds to it. Now using a spoon, stir the water. Increase the speed of stirring. What do you see in the water? In the centre, there is a depression. Around it, the water spins fast. What happens to the seeds? They are in the centre. Are they going round and round? No. They are not making any fast movements. 55 181010045-Alpine-G5-Textbook-Science-FY.pdf 59 03-Feb-18 2:41:39 PM
A cyclone may look like this. It has a calm centre called the eye. Around the eye, winds blow at a high speed. Cyclones are formed over the ocean. They move towards the land. They bring heavy rains along with them. Understanding When cyclones hit land areas, the powerful winds destroy everything in their way. They may uproot or break the trees, blow away the roofs of buildings, displace and damage vehicles and electrical posts and so on. Cyclones push the sea water into the land. They also bring heavy rains with them. Strong rains last for hours or even days. All these lead to floods. A flood a tree uprooted by a cyclone view of a flooded area in is a sudden rise in the water in Andhra Pradesh Odisha after a cyclone level making land areas submerge in water. Application Cyclones affect the lives of all the people living in cyclone-hit areas. Flood water may cover and wash away farms, roads, buildings and so on. It makes all the sources of water unfit for drinking or bathing. Floods may damage crops in the fields as well as stored food grains. Houses and vehicles may be damaged due to the flood waters. People may become homeless. During such disasters people need support. They need food, clean drinking water, clothes, a safe place to stay and so on. So, the government arranges temporary shelters rescue camps or shelters for the affected people. At the rescue camps, these cyclone-affected people are provided with food, water and clothes. Flood water may take days to drain off. By that time, disease-causing mosquitoes, flies and other insects may increase in number. This may lead to the spread of many diseases. Hence, medical camps are also set up to give medical support to people. 56 03-Feb-18 2:41:39 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 60
Amazing Facts Do you know that cyclones are given names? Some of the recent cyclones which hit India were named as Vardah, Hudhud, Nilam, Laila and so on. They are not named after any people. Naming helps the people to understand and remember the cyclones easily. All the messages related to a cyclone can be sent and received mentioning these names. Higher Order Thinking Skills (H.O.T.S.) It is not possible to control cyclones. But the damage to life and property can be reduced by preparing for it in advance. For this, we must know about an approaching cyclone in advance. These days, with the help of satellites, the government gives cyclone alerts 48 hours in advance. Then, cyclone warnings are given 24 hours in advance. Thus, the people can prepare in advance. When a cyclone alert or warning is satellites help to predict cyclones given, we should listen to the radio and television to get updates about the situation. Cyclones and Floods 57 181010045-Alpine-G5-Textbook-Science-FY.pdf 61 03-Feb-18 2:41:39 PM
Lesson Earthquakes and Tsunami 13 Let Us Learn About R earthquakes. u causes of earthquakes and how a tsunami occurs. a harmful effects of earthquakes and tsunami and responses to them. h precautions to earthquakes and tsunami. Think Pavan was holidaying with his family at a seaside resort. One day, early morning, suddenly the ground started to shake. His father asked them to get out of the room and rush towards the lawn. Pavan could not understand what was happening. Do you know what happened? Remembering Sometimes the ground shakes. It may move up and down and may crack open. This is an earthquake. An earthquake is a shaking of the Earth’s surface. It is a natural disaster. Earthquakes do not last for more than 30 seconds at a time. But, they may repeat. The strength of the quakes is different. Some of them are weak, while others are strong. A device called the seismograph is used to measure the strength of the quake. seismograph 58 181010045-Alpine-G5-Textbook-Science-FY.pdf 62 03-Feb-18 2:41:39 PM
Every year, a large number of earthquakes occur in different the Pacific ring of fire places in the world. In some places of the world, the earthquakes happen often. Most earthquakes happen along the edges of the Pacific Ocean. So, this area is called the Pacific ring of fire. Understanding Why do earthquakes happen? Let us find out. Let us do an activity. Take a few cardboard pieces. Arrange them on a table close to one another. Place a few pencils, pens, erasers, sharpeners and so on over it. Now, pull two adjacent cardboard pieces slightly apart. What happens to the things you kept over it? They shake and tumble. Now, push two cardboards against each other. What happens? Their edges may bend, or one of them may slide over the other. All the things over it shake and get displaced. Earthquakes happen in a similar way. The Earth has layers. The upper layers are thin and broken into pieces. They float over the inner part. While floating, these pieces may collide or move apart. This causes earthquakes to occur. Let us do another activity. Take a thin plastic tray. Fill it with water. Lift it holding the edges. broken upper layers Now, ask another person to give a light bang on the lower part of of the Earth the tray. Observe what happens to the water. Bang a little harder. Observe the changes in the water. What do you find? A bang on the tray creates ripples in the water. They start from the point where we bang and move towards the edges. Now, imagine the same situation happening in an ocean. An water ripples earthquake bangs the ocean floor. Then, waves will be formed in the ocean. They travel towards the shores. Sea shores are shallow. So, the waves do not have enough space in the water to move up and down. So, they rise like huge walls of water and lash over the coast. These huge waves are called a tsunami. Tsunami is a Japanese word meaning ‘harbour wave’. tsunami moving towards the shore Earthquakes and Tsunami 59 181010045-Alpine-G5-Textbook-Science-FY.pdf 63 03-Feb-18 2:41:39 PM
Application Small earthquakes can topple a few buildings and crack roads. But, big earthquakes can destroy entire cities. Every year, around 10,000 people die due to earthquakes. Deaths happen when people are trapped under fallen buildings. The tsunami formed after an earthquake can destroy entire coastal areas. The waves may travel long distances into the land. On their way, they will sweep away buildings, vehicles, roads, trees and so on. Tsunami leads to the death of many people. tsunami waves wash off buildings and vehicles In 2004, an earthquake happened in the Indian Ocean. The tsunami waves formed due to this earthquake killed 2,27,898 people. It was one of the deadliest natural disasters in the world. When an earthquake and tsunami occur, government and some other agencies help the affected people. They begin the search to find people who may be trapped under toppled buildings. They set up relief camps for rescued people to stay safely. Also, they arrange for food, drinking water and clothes for these people. Doctors are there at the camps to treat injured people. After rescuing people and ensuring they are safe, the government begins the rebuilding process. Schools, roads, hospitals, houses and so on are rebuilt, if damaged, for people to go back to a normal life. Amazing Facts In 2009, an earthquake happened near the Samoan islands in the Pacific Ocean. The wave formed was just 7.6 centimetres high. But, when they reached the New Zealand coast, the height of the waves was 14 metres! 60 03-Feb-18 2:41:39 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 64
Higher Order Thinking Skills (H.O.T.S.) We cannot stop or control earthquakes and tsunami. But, we can prepare for them. 1) We can build houses that can withstand earthquakes. Tall buildings fall easily. One or two level houses are safer. We can make houses using light materials. Even if they tumble, they will not cause much harm to the people. 2) We should not build houses near the seashore. They should be at a safe distance from the shore. 3) During an earthquake, if we are in a building, it is important to get out of it quickly. The building may collapse, or heavy objects may fall on us. 4) We should avoid using the lifts and other electrical equipment at such times. 5) It is important to leave everything and vacate the building as quickly as possible. 6) When we get a tsunami alert, we should move out of coastal areas. Earthquakes and Tsunami 61 181010045-Alpine-G5-Textbook-Science-FY.pdf 65 03-Feb-18 2:41:39 PM
Lesson Simple Machines 14 Let Us Learn About r what simple machines are. u types of simple machines. a uses of simple machines. H the simple machines in the human body. Think Have you ever played on a see-saw with your friend? How can it lift you up and bring you down? Remembering Have you seen people loading or unloading heavy loads from a truck? How do they do it? They use a sloping surface for this purpose, so that they can roll the load on it. Have you seen your dad or a carpenter putting a nail in the wall? What do they use? Why do they need a hammer? using a slope to unload using a hammer to put in a nail 62 181010045-Alpine-G5-Textbook-Science-FY.pdf 66 03-Feb-18 2:41:39 PM
Have you seen people drawing water from a well? They use a wheel and rope to pull it out easily. What do the carpenters use drawing water from a well using joining wooden planks together to put the wooden planks a wheel and rope together while making furniture? We see many examples in our day-to-day life where we use some simple devices that make our work easy. These are simple machines. Simple machines are the devices that make the work easier. These machines have few or no moving parts. They are used to apply force to move objects. We need less effort to move the objects because of them. They can do the work with less force. Following are the six simple machines: simple machines inclined plane, wedge, pulley, screw, lever, wheel and axle Understanding Let us now understand how these simple slope wedge machines work and make things easier. inclined plane cutting wood using 1) Inclined plane: A sloping or slanting surface a wedge (axe) makes an inclined plane. The slant of the inclined plane can move an object from one level to another. 2) Wedge: A wedge is a simple machine. It is used to separate any two objects by pushing them away from each other. Wedge is also like an inclined plane. It has a slanting edge which is sharp. It can be used to lift things. Most of the times, it helps us in cutting something. Example: an axe used to cut wood Simple Machines 63 181010045-Alpine-G5-Textbook-Science-FY.pdf 67 03-Feb-18 2:41:39 PM
3) Screw: A screw is a type of inclined plane. In a screw, an inclined plane is twisted (swirled) around a rod like a road around the hill. Screws are useful for putting things together tightly. Example: screw is used to connect two wooden or metal blocks together screw twisted roads 4) Pulley: A pulley is a wheel with a rope around it. Pulleys make lifting objects easier. For example, cranes use pulleys to lift heavy vehicles and building materials. 5) Wheel and axle: Wheel and axle make work easier by reducing friction. A wheel helps things to move. The axle helps the wheel turn. Example: wheels of a bicycle and other vehicles axle wheel pulley crane using the pulley wheel and axle bicycle wheel with axle 6) Lever: Lever is a bar, rod or a platform that can move about a fixed point. The fixed point is called a fulcrum. Fulcrum is a fulcrum point where the lever touches the support. A lever makes it easier to move a large load with little effort. Example: see-saw lever kids playing on a see-saw Application Simple machines are useful in many ways. We see them being used every day. Let us look at some examples in our day-to-day life. 64 03-Feb-18 2:41:39 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 68
Inclined plane: The staircase we use to climb and the ramp used to carry loads are inclined planes. Wedge: Axe, knife and needle are a few examples of a wedge. Inclined planes Wedges staircase ramp knife axe Screw: We use so many screws in wooden furniture. The bottle caps are also a type of screw. Pulley: The rope and wheel used to draw water from a well and a crane used to lift heavy objects are a few examples of a pulley. Screws Pulleys bottle cap screws used pulley used pulley used in crane in furniture to draw water Wheel and axle Wheel and axle: Door knobs and steering wheels of the cars are a few examples of wheel and axle. Lever: We use scissors to cut so many things in our house. door knob steering wheel How do you open a cold drink bottle? When we use a bottle opener, it takes less effort to open. The stapler we use to staple papers is a lever. Levers scissors bottle opener stapler 181010045-Alpine-G5-Textbook-Science-FY.pdf 69 Simple Machines 65 03-Feb-18 2:41:39 PM
Amazing Facts Bicycle is a complex machine that uses simple machines like two wheels and an axle. Higher Order Thinking Skills (H.O.T.S.) bones and muscles act like levers Do you know our body parts also work as simple machines? Let us find out how. • Our teeth help us to cut with the edge; they act like a wedge. • Our knee and shoulder joints act like wheel and axle. • Our bones and muscles act like levers. The joints where the bones meet becomes the fulcrum. Muscles provide with the effort. A load is anything that we lift, push or pull. Mark the effort, fulcrum and load in the given picture. 66 03-Feb-18 2:41:39 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 70
Inside the Lab – C Make sure you do these activities only with the help of a teacher or an adult. Activity C1: Simple Machine We have learnt that simple machines help us to do different types of work easily. Let us make a simple machine using some pencils. Let us also find out how they make the work easy. You will need: one brick per group, 10 pencils per group You need to: 1) divide the class into groups of four. 2) ask a student from each group to push a brick across the floor or a stone slab. Is it an easy task? 3) ask each group to take 10 pencils. How could you move the brick more easily using the pencils? Take group members’ suggestions. 4) put the pencils under the brick and roll it across the pencils. Was it easier this time? 5) move other things such as books in the same manner. See if there is a difference. Find out how people in the olden times may have used this simple machine to move big objects. Activity C2: Catapult A catapult is a simple machine used to throw stones or any object. Let us make a simple catapult using some easily available materials. Let us also find out how they help us to throw stones easily. You will need: nine craft sticks or ice cream sticks, six good quality rubber bands, one plastic spoon 181010045-Alpine-G5-Textbook-Science-FY.pdf 71 67 03-Feb-18 2:41:39 PM
You need to: 1) take seven craft sticks, and tie one rubber band each tightly around two ends to bound them all together. 2) take two sticks, and tie a rubber band on one of the ends. Try to tie the rubber band close to the edge of the sticks. 3) insert the stack of seven sticks through the two stick bundle. 4) tie these two pieces with a rubber band in a cross fashion as shown in the given image. 5) use few rubber bands, and attach the plastic spoon at the open end of the two sticks. 6) try catapulting pebbles or other small objects. 68 03-Feb-18 2:41:39 PM 181010045-Alpine-G5-Textbook-Science-FY.pdf 72
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