CLASS 4 - TERM-1 PRIME YEARS

Divisibility by 5 If the units digit is 5 or 0, the number will be divisible by 5. Example: 125, 420, 3250, 1385, 2240, 1185 are divisible by 5. Divisibility by 6 If a number is divisible by 3 and 2, it will be divisible by 6. In other words, all even numbers that are divisible by 3 are divisible by 6. Example: 120, 1812, 4152, 54, 186. Divisibility by 9 If the sum of digits of a number is divisible by 9, the number is divisible by 9. Example: 1728. 1+7+2+8 = 18 18 is divisible by 9. Hence, 1728 is divisible by 9. See whether the following are divisible by 9. (1)1872 (2) 216 (3) 3006 (4) 6715 (5) 845 Divisibility by 8 If the number formed by the digits in the units, tens and hundreds places is divisible by 8, the number is divisible by 8. Example: 128 is divisible by 8. So, 6128 is also divisible by 8. Similarly, 4248, 1728, 5280 are also divisible by 8. Divisibility by 10 If the units digit of a number is 0, the number is divisible by 10. Example: 100, 120, 3280, 1150…… 101

1. Circle the numbers divisible by 3. 253, 138, 81, 152, 1287 2. Circle the numbers divisible by 4. 124, 2532, 1587, 1291, 824 3. Circle the numbers divisible by 6. 156, 1202, 2524, 1152, 1314, 1026, 1828 4. Circle the numbers divisible by 9. 8334, 5103, 306, 752, 1106 Given on the right is a maze. Enter it through a number divisible by 3. The way to exit can be found through numbers divisible by 3 or 6. 728 153 274 1583 379 72 183 282 753 1006 703 109 324 287 2104 1102 107 1206 2304 218 407 1124 1214 212 81 102

Shapes and patterns If you look around, you can see many patterns in nature. Patterns in the growth of trees, arrangement of leaves, whirls in flower clusters, vein patterns in different leaves are just some examples of patterns in nature. 103

Activity 1: Look around and find more patterns in nature. Draw them in your note book. Patterns in numbers: This requires geodot paper. Look at the geodot patterns. Look at the pattern of the enclosed dots. You will notice that enclosed dots grow like: 1, 1+3, 1+3 + 5, 1+ 3 + 5 + 7………. What pattern is obtained by adding odd numbers? 1 + 3 = 4 1 + 3 + 5 = 9 1 + 31 – 5 + 7 = 16 1, 4, 9, 16…………….are called square numbers 104

Square numbers can be written as: 1 x 1, 2 x 2, 3 x 3, 4 x 4, 5 x 5……… The geodot pattern, shown above, gives square numbers. The square numbers are obtained by adding odd numbers as shown. Find the first 10 square numbers by enclosing them through lines on the given geodot paper. Activity 2: Here is another number pattern. Study the pattern in which the squares grow and write down the number sequence of the pattern. Note: This number sequence is called Fibonacci series. Sides of the squares are given by the numbers of the sequence. Copy this diagram in your notebook. Draw the next two squares in the pattern. Write down the sequence in which the sides of the squares grow. 1 1 2 3 5 2 5 3 5 3 105

Activity 3: How many triangles are there in the given figure? How many squares are there in the given figure? Patterns in plane shapes Activity 4: Complete the given pattern for 3 more rows. Complete one more star in the given pattern. 106

What all can you make from a circle? A few ideas are shown here. Try 5 more. A human figure made from a triangle is shown here. Try to make a human figure with rectangles only. Activity 5: This requires paper cut outs. 1. Make a square from a rectangle by folding the paper along the dotted lines. 2. Make a parallelogram from a rectangle by folding it. Fold along the dotted lines. The resulting figure is a parallelogram. 3. Make a trapezium from a rectangle by folding the paper along the dotted lines. The resulting figure is a trapezium. 4. Make a rhombus from a rectangle by folding the paper along the dotted lines. 107

3D shapes Making 3D shapes from plane shapes. Activity 6: Draw same figures on paper, cut them out, and fold them into solid shapes. Note: All squares must be of the same size. Better use a square ruled paper to draw the figures. Cuboid Pyramid – Draw on a square ruled paper. All the triangles should be identical. 108

Drawing 3D shapes on geodot paper. Try drawing these figures on a geodot paper. Try another one with a left orientation. The given figures have right orientation. Verification of Euler’s formula Euler’s formula states that in a solid, the number of vertices + faces – edges = 2. That is, V + F – E = 2 Study the different solids, fill in the given table, and verify the formula. Shape Vertices Faces Edges V + F – E Cube Cuboids Square Pyramid Cone Cylinder Sphere 109

1. Make drawings of figures made in the activities and fill them with color to make beautiful designs. Prepare an album with the shapes and patterns so made. 2. Take solid shapes available at home. Keep each one on a paper and draw the bases’ outline. What is the plane shape you get? Take card board cutouts of a square, a rectangle, a circle and a triangle. Rotate each one about any one corner- what solid shape is generated by spinning the plane shapes? Draw them as you visualize. 110 Look for different solid shapes at home, at school and on your way to school.

Contents 1. Components of food ________112 2. Importance of healthy food ___119 3. The process of digestion_____127 4. Teeth structure and Microbes _133 5. Safety first _______________138 6. Preservation of food ________144 Class 4 Term 1

Components of food We all know that food gives us energy. Food has some other functions too. Food helps the body grow and keeps it healthy.The food that we eat has many components, each performing a specific function. Carbohydrates in the food give energy; Proteins help in body growth; Vitamins and minerals keep the body healthy and free of diseases. 112

A meal that contains all the components in the required proportion is called the balanced diet. Let us learn about each component in detail. Carbohydrates: Carbohydrates are broken down into glucose during digestion. When glucose reaches the cells in our body, it releases energy and carbon dioxide. The energy so released helps the body in doing work. Rice, wheat, other cereals, and sugar are carbohydrate rich foods. Fats and oils also produce energy. Proteins: Proteins are broken down into peptones during digestion. Peptones are further converted to protoplasm in our cells. This helps in cell multiplication, which results in body growth. Pulses like green grams, Bengal gram, red gram, black gram, meat, milk, fish and eggs are rich in proteins. Vitamins: Fruits and vegetables contain vitamins. They are chemical components which help to keep the body free of diseases. 113

Study the table given below: Sources Vitamins Diseases caused by the deficiency Vitamin - A Carrot, papaya, green leaf, vegetables, pumpkin, cheese, egg, milk. Night blindness Vitamin - C Citrus fruits, grapes, strawberry, gooseberry, amla Scurvy- bleeding of the gums Milk, butter, egg, fish, sprouted grams, sunlight Rickets – bending of bones. Green vegetables, vegetable oil, beans grains, egg and milk Vitamin - K Vitamin - E Vitamin B - a mixtures of 8 vitamins B1, B2, B3, B5, B6, B7, B9, B12, collectively known as B complex Green vegetables, vegetable oil, beans, grains, egg and milk Bread, meat, peas, rice bran, milk green vegetables, whole grains, fish, chicken Haemophilia - bleeding from wound doesn’t stop as blood doesn’t clot Function of red blood cells affected B1 – Beriberi – affects nerves and heart B3 – Pellagra- cause red sores B12 – anaemia and memory loss. Vitamin - D 114

Minerals: Calcium is a component of our bones. It is required for keeping our bones strong. Deficiency of calcium in our body increases the risk of fracture. Calcium is primarily present in milk, dairy products, white bread, seeds, nuts, and green vegetables. Iron: It is vital for the formation of anaemia in our body. Deficiency of iron causes anemia. Apple, banana, spinach, brinjal, dates, and meat contain iron. Iodine: Deficiency of iodine causes a disease called goiter, which affects the thyroid gland in our body. It is present in sea food, milk, iodized salt or salt made from sea water. Salt prepared from salt rocks does not contain Iodine. Potassium: It regulates our heart beat and blood pressure. It is present in fruits, vegetables, pulses, meat and fish. Vitamins A, D, E and K are fat soluble. Other vitamins are water soluble. Precautions while cooking vegetables Most vitamins are water soluble. That means that most of them will go into water when vegetables are boiled. Therefore, when you boil vegetables, don’t drain off the water. It is better to steam cook or shallow fry the vegetables in order to retain their vitamins. 115

1. Haemophilia – difficulty in clotting of blood. 2. Anaemia – lack of red blood corpuscles in the blood. 3. Thyroid gland – a gland that secretes thyroxin, a hormone. It is situated in the neck region. 4. Balanced diet – a diet that includes all the components of food in the right proportion. 1. Name the components of food. 2. Mention 5 energy giving food items. 3. Mention 5 food items that are rich in protein. 4. Name three minerals required by the human body. 5. What is a balanced diet? 6. Choose the correct answer. a. Anaemia is caused by the deficiency of (iron/iodine) b. Goiter is a disease caused by the deficiency of (calcium/iodine) c. Bending of bones is called (rickets/beriberi) d. Pulses are rich in (carbohydrates/proteins) e. A water soluble vitamin (vitamin A/vitamin C) 116

1. Why do doctors advise exposure to sunlight in the early morning? 2. Why should green vegetables be cooked in the least quantity of water? 3. Why bleeding doesn’t stop for some people when any part of their body is wounded? 4. Why is goiter common among people who live in the mountainous regions? 5. Why is milk called an ideal food? Do it in groups. Each group takes up one component of food. Make masks with fruits, vegetables, cereals, meat, fish, egg, milk and other food items. One student will stand with a placard showing each of the components of food- carbohydrate, protein, fats, vitamins and minerals. Students wearing respective masks should stand around the student holding the relevant placard. 117

Write the given food items under different headings - carbohydrates, proteins, vitamins minerals, fats and oilsidly, chapatti, rice, ice cream, milk, sugar, apple, lemon, cabbage, spinach, onion, brinjal sprouted beans, green gram, fish, meat, butter. Refer to the table given in the lesson on vitamins and their functions, and answer the following questions: 1. Name the vitamin that helps stop bleeding of wounds. 2. Name the disease caused by deficiency of vitamin C. 3. What are the vitamins included in B complex? 4. Which vitamin prevents pellagra? 5. Which vitamin prevents Beriberi? 6. Which vitamin is present in papaya? 7. Deficiency of which vitamin causes rickets? 8. Which food item contains all the vitamins except vitamin C? 9. What is the main source of vitamin C? 10. Which vitamin is produced in our body by sunlight? Copy this table in your notebook and fill it up. Carbohydrates Proteins Fats and oils vitamins and minerals. 118

Importance of healthy food Sometimes, the food that we eat can cause health hazards. There are various reasons for food being hazardous. 1. Spoiled food – Role of micro organisms Stale food: 1.Food, if kept for a long time, becomes stale due to the action of microbes. Such food, instead of providing nutrition, will cause diseases. That we call as food poisoning. 2. Food kept in the open is acted upon by microbes in the air and makes it unfit for consumption. 3. Food kept in open invites insects like housefly, cockroaches, lizards etc and becomes infected 4. Fruits and vegetables get decayed if kept for many days. It is because they are acted upon by microbes. If they are cooked and eaten, they cause many diseases. What are microbes? Microbes are micro organisms like bacteria, fungi, amoeba, yeast etc. They cannot be seen by the naked eye. They can be seen through microscopes only. Stale food 119

Keep a slice of wet bread in a corner of a room or window and cover it loosely. Observe it after 2 – 3 days. You will see black patches on the bread. These black patches are fungi. They are called bread mould . Any cooked food item if kept in open for a few days will develop fungi. Bacteria: These are micro organisms that spoil food by bringing in chemical changes in the food materials. Some bacteria are useful, but most of them are harmful. Curdling of milk is due to the action of bacteria called Lactobacillus. It is a useful bacteria. Fermentation of dough, which is used to make idly, dosa etc. is due to the action of bacteria. However, most bacteria cause diseases like malaria, cold and cough etc. Bacteria can be seen only under the microscope. Some bacteria present in air convert nitrogen into nitrates, which is a nutrient for plants. Bacteria 120 Bread Mould

Yeast: Yeast is another useful micro organism. It is used to ferment batter for cake, bread etc. Prepare a sugar solution. Put some yeast tablets in it. Yeast tablets are available in medical shops. Look into a drop of the solution through a microscope. Draw what you see. Keep the solution for one or two hours. Again, test a drop of the solution. This time, you will see many more number of cells. Draw it. Observe the difference between the two drawings. Yeast is used in fermentation of sugarcane juice to form alcohol. Amoeba: Bacteria, fungi and yeast are micro plants, whereas amoeba is a micro animal. It is a harmful microbe. It passes into human body through air, water, and food. It causes many ailments. Amoeba Contractile vacuole Cell membrane Cytoplasm Pseudopods Food vacuole (digests food) Nucleus 121

2. Agricultural Process Nowadays, chemical fertilizers are used to grow crops. Many insecticides and pesticides are sprayed on the plants right from the sprouting stage in order to protect them from insects and pests. Traces of these killer chemicals enter the grains, fruits, and vegetables, and thus, enter our body too. These chemicals affect the functioning of organ systems in our body. 3. Preservatives Fruits and vegetables kept for sale are sprayed with preservatives to prevent them from decaying. There are chances that traces of these preservatives get into fruits and vegetables, thus harming them. 122

4. Adulteration Food materials that we buy from shops are sometimes adulterated. Unwanted or harmful ingredients are mixed with food materials before they are packed. For example, red brick powder in chili powder, yellow chemical substance in turmeric powder, wild seeds in edible pulses, Dalda in butter, cheaper oils in expensive oils etc. are commonly mixed. Adulterated food is harmful for consumption. Though a consumer forum is set up to look into cases of adulteration, most of the times, consumers ignore the warnings and never bother to check the commodities for adulteration. 5. Ready to cook products Nowadays, ready to cook food items are readily available in the market. We buy them in large quantities in order to save time in cooking. However, in order to prevent them from spoilage for many months, preservatives are used in these food items. Excessive consumption of such food items can be harmful for the body. 6. Fast food centers Fast food centres provide tasty food within no time. They supply Indian, Chinese and continental dishes at a moderate price. However, we don’t realize the risk involved in consuming these fast foods in large quantities. They have a high measure of spices and fat. In the long run, these foods lead to many health disorders like obesity and heart problems. Moreover, the fast food centres may not follow the rules of hygiene. The cooking and serving places at these centres may not be clean. 123

7. Footpath Vendors Often, people can be seen eating food from roadside vendors. However, this can pose a health hazard. Often, vessels used by such vendors may not be clean, mixing of ingredients may be done by unclean hands, and the ingredients may not be fresh. All these factors contribute to frequent occurrence of diseases. How do we ensure that the food we eat is healthy and clean? Complete redemption from unhealthy components in food is not possible. However, it can be reduced if we are little cautious. 1. Wash fruits and vegetables in running water and rub them well with fingers before use. Luke warm water is better for this purpose. Even grains should be washed well. 2. Don’t eat decayed fruits and vegetables. 3. Packed food materials should be avoided as far as possible. If you must eat them, always see the expiry date printed on the packet. If the expiry date has passed, don’t eat it. 4. Don’t visit fast food centres and restaurants frequently. Home made food is the best. 5. Avoid over consumption of fats and sugar. 6. Don’t eat from roadside eateries. 7. While cooking vegetables, don’t drain off the water that is used for boiling them. While cooking rice too, don’t drain the water off. 8. Use only filtered water for cooking and drinking purposes. Water filter is a must in every household. 124 Food path Vendors

1. Food poisoning - problems in digestion due to contaminated food. 2. Micro organisms - living organisms that can be seen only through a microscope. 3. Curdling of milk - milk changing to curd. 4. Preservatives - chemicals used in food items to save them from spoiling 5. Redemption - freedom. 6. Adulteration - mixing harmful materials with food items. 1. What are the sources of food contamination? Mention them. 2. What are microbes? Mention a few. 3. Give three examples of useful microbes. 4. What are the agricultural practices that lead to food contamination? 5. Mention a few cases of food adulteration. 6. Why should we not eat from roadside eateries? Put up a skit to compare food habits in your grandfather’s time and now. Prepare the skit in the form of questions and answers. 7. Imagine yourself to be a microbe. Write a short essay on how microbes cause health problems. 125

From the web, get more information on consumer forums set up in order to ensure that food articles are not adulterated and what they do? 1. Why is it better to carry home food while travelling in bus or train? 2. Steaming is a better method of cooking than boiling. Why? Read the extract on ‘How do we ensure that the food we eat is healthy and clean’ . Write a speech on the importance of healthy food. 126

The Process of Digestion The food we consume undergoes the following changes in our body: Digestion – absorption – assimilation - excretion of waste Breaking down food into water soluble particles is called digestion. Food is digested in our digestive system. The digested food is absorbed by the blood and is carried to the tissues. The tissues assimilate the nutrients. During the process of assimilation, energy is released and carbon dioxide is given out as waste. The undigested food in the intestine is excreted as stool. rectum Let’s learn about our digestive system What are the different parts of our digestive system? Read from the sketch given and write in order from top to bottom. Let’s learn the function of each part of our digestive system Mouth: Chews the food and converts the starch into sugar. It pushes the food into the Esophagus. Digestive juice called saliva helps in the chewing process. mouth small intestine large intestine gall bladder oesophagus (food pipe) stomach liver 127 Process of Digestion

Oesophagus: It slowly pushes the food into the stomach. It is also called food pipe. Stomach: It churns the food into a fine pasty mass. It works like a grinder. The carbohydrates in the food are converted by the digestive juices in the stomach to glucose. Proteins are converted into peptones and amino acids, fats and oils are converted into fatty acids. Liver: Liver secretes a digestive juice called bile. It is stored in the gall bladder and mixes with the food in the stomach. Bile contains a digestive juice called insulin. Small intestine: The digested food from the stomach enters the small intestine. Whatever undigested food remains is completely digested in the small intestine. The undigested proteins and peptones are converted into amino acids. The digestive juice from pancreas helps in this process. From the small intestine, the digested food is absorbed in the blood. The small intestine is more than a metre long. However, it is coiled up in a small space. Saliva is a digestive juice that converts starch into sugar. The fibrous material in the food is not useful to the body. It helps in digestion and excretion. It is called roughage in medical terms. The disease jaundice is caused by excess bile passing into the blood stream. Acidity is caused by certain food items that cause production of more acid in the stomach. It is neutralized by antacids like gelusil. 128

The undigested food passes into the large intestine. There, the water in the food is absorbed and the solidified waste is given out through rectum. If there are more fibrous food items in our diet, it makes excretion easy. That is why, doctors advice to take more fibers in our food. Role of insulin Insulin helps to control blood sugar levels. It helps to store extra sugar in the liver. If insulin is insufficient, all the sugar passes into the blood and urine, and also accumulates in the tissues. This is called diabetes. Diabetic patients should avoid sugar and also have regular intake of insulin. 129 Healthy food habits 1. Wash your hands before eating food. 2. Eat at regular intervals. 3. Chew the food well before swallowing. 4. Don’t eat in a hurry. 5. Avoid too much oil and fat in the food. 6. Drink a glass of water after the meal.

1. Digestion: Breaking down food into fine particles by the action of chemical substances called enzymes. 2. Carbohydrates: Starch and sugar present in food items. 3. Excrete: give out 4. Gallbladder: the organ that stores bile, a digestive juice . 5. Pancreas: an organ that produces digestive juices. 6. Digestive juice: a fluid that contains chemical substances called enzymes . 7. Peptones: Proteins in food are broken down into simpler compounds in our digestive system. These are called peptones. Peptones are again broken down to amino acids . 8. Tissues: Group of cells performing specific functions . Identify the organ: a. Produces saliva _______________ b. Gives out the wastes after digestion ________________ c. Produces insulin ________________ d. Food is absorbed into the blood from here ______________ e. Churns the food into a paste ______________ f. Pushes the food into the stomach __________________ 130

1. What is digestion? 2. List the organs in our digestive system in order. 3. What happens to food in our mouth? 4. What causes acidity? What is the remedy? 5. What is the function of the large intestine? 6. Mention the changes that occur in various components of food during digestion: a. Carbohydrates b. Proteins c. Fats and oils 1. Have a group presentation on digestive system. Each group takes up one organ and explains what happens to the food in that organ. Use photographs, CD’s, or other displays. 2. Prepare a chart to display healthy food habits. It can be a group activity. 3. Make a model of the digestive system using modeling clay. Use different colours for different organs. Do it as a home assignment or work in groups in the school. 4. Collect more information on insulin and its functions and what causes diabetes. Write on essay in about 150 - 200 words. 131

Label the parts shown by the lines in the digestive system of human beings. 132

Structure and functions of teeth Permanent Teeth Teeth are a very important part of our body. They give proper shape to the face and help in digestion. If teeth are not in good condition, it will affect our digestion and also make it difficult to eat the food we like. Teeth help in cutting and chewing food. 133

Milk teeth: When a baby is born, it doesn’t have teeth. Teeth start growing from the 6 month onwards. By the age of three, a child will have th about 20 teeth. These are called milk teeth. When the child attains the age of 6, the milk teeth start falling and new teeth start growing from the gum. These are called permanent teeth. If a permanent tooth is lost by any chance, it will not grow again. Therefore, it is very important that we should take care of our teeth. Kinds of teeth There are four kinds of teeth in humans - incisors, canines, premolars and molars. 1. Incisors: They are used for cutting and biting food. They are sharp. We have 8 incisors, 4 in the upper jaw and 4 in the lower jaw. 2. Molars: There are 3 molars on either side on the upper and lower jaw. There are 12 molars in total. They help in chewing food. Tooth (section of a molar) 134

3. Canines: There are two canines on the upper jaw and two on the lower jaw on each side of the incisors. They help to tear fibrous food items and meat. They are pointed and sharp. 4. Premolars: There are two premolars on either side of the canines. They are 8 in number. They help in cracking nuts and other hard food items. Parts of a tooth The teeth are held by the gum. Each tooth has two parts- the crown and the root. The crown is the white visible part. The root is fixed into the gum. Internal structure of the teeth: Teeth are white because they are coated by a white substance called enamel. Inside the enamel is a hard part called dentine. Inside the dentine is pulp which contains blood and nerves. The nerves are connected Internal structure of the teeth 135

to the nervous system. We experience pain in the teeth because of the nerves. Enamel: Enamel protects the teeth. If enamel is removed, the teeth get spoiled very fast. Very hot and very cold food spoils the enamel. Eating too much ice-cream and consuming cold drinks also lead to loss of enamel. The tickling sensation we get when icecold food items touch the teeth is due to the lack of enamel on the teeth. Tooth decay There are many reasons for tooth decay, such as: 1. Not brushing the teeth properly. 2. Consuming very hot or very cold food items. 3. Eating lots of sweets. When we don’t brush our teeth properly, bits of food can remain stuck in our teeth. The unclean tooth in due course develops a coating of germs called plaque. This coating of germs produces acids when it comes in contact with sugary food. The acid so produced removes the enamel and the teeth are exposed. Thus, we experience pain when they come in contact with food. Exposure of the pulp also leads to formation of cavities in the teeth. Care of teeth We all know what is to be done to take care of our teeth. In advertisements, doctors give suggestions to use a particular toothpaste or toothbrush. We know that 1. We must brush our teeth in the morning and before going to bed at night. 2. Eating raw vegetables like carrot, cucumber and fruits like apple, oranges, guava help to keep the teeth strong. 3. Eating too many ice-creams and chocolates should be avoided. 4. Drinking milk daily helps to keep teeth strong. 136

1. Identify the teeth a. Cutting and biting on to food items b. Tearing fibrous food items c. Chewing teeth 2. What are these ? a. Teeth are fixed into this b. White coating on the teeth c. This part of the teeth contains blood and nerves d. The hard part of the teeth exposed when enamel is removed 1. Draw the arangement of teeth in the mouth and label the different teeth. 2. Draw and label the structure of the tooth. 137 1. Collect more information on tooth decay and tooth ailments from a dentist. 2. Form pairs. Examine each other’s teeth. How many of each kind does each of you have? Write them down. 3. Collect popular brands of toothpaste. Find out the ingredients in each. Which one is the best according to your analysis? 4. What materials did people use to clean their teeth in olden days? Get information from your grandparents.

Safety First Discuss in pairs or groups, and guess the accidents that may occur in each case. 1. Some students are running in the school corridor pushing each other. 2. Some students are stepping down the stairs in a hurry. 3. Some children are playing with electrical plugs and plug points. 4. It is interval time. Children are jumping up and down on the benches and desks in the classroom. They are running around in the class, pushing each other. 5. Children are hitting and pushing each other in their bid to catch the ball. Right from class I, you have been told about the do's and don’ts to avoid accidents and keep yourself safe. Given below are a few situations involving accidents and first aids. Take a look and discuss among yourselves. 138

6. Children are swimming in the swimming pool. The coach is not present anywhere near the pool. 7. Some children are pelting stones at a beehive on the tree. Each group should read out what it came out with. In the end, there is a discussion in the class and teacher gives a list of accidents that can occur in the given situations. What are the causes of road accidents? Students should discuss in groups and come out with their views. At the end, teacher explains the causes of accidents on roads. Compare your views with what is given below. 139 Causes of road accidents 1. Not following traffic signals. Red light means to stop; yellow means get ready; and green means go. 2. Not reading traffic signs. You might have seen certain signs on the roadside. A few are given below: a. Maintain the speed limit b. Walk along the left side of the road. c. Cross the road only at Zebra crossing. d. Don’t overtake from the left side. e. Don’t use cell phone while driving. Stop School zone No right turn No parking No 'U' turn

First aid 140 3. First aid for burns: Pour ice cold water on the burnt area. Ice crystals can be gently rubbed on the burnt area, but be careful not to burst the blisters, if any. Antiseptic creams like Burnol can be applied on the wounds. If it is a serious burn, take the person to a hospital. Avoid wearing synthetic clothes while cooking as they catch fire easily 2. First aid for fracture: A tourniquet can be made for fractured arms. However, it is better to call an ambulance and take the person to a hospital. 1. First aid for injury: Wash the injured area, apply antiseptic cream, and wrap it with bandage cloth. If it is a serious injury, take the person to a hospital. Ambulance

4. Electric shock: First disconnect the source of electricity. Don’t touch the person when he is still in contact with the source of 141 First-aid kit What are some common things found in a first aid box? Your school will have a first-aid box. Find out what are the things kept in the box. There is a sign in red over the box. What does it mean? Where else have you seen that sign? electricity. Use wooden poles or rubber gloves to disconnect the plug and release the person from the switch or plug. 5. Insect bite: Scorpions, centipede, wasp and honeybee are common insects that bite people. In the case of insect bites, apply lime or baking soda on the affected part, followed by cold cream to reduce the burning sensation.

1. First aid - Immediate medical attention given to an ailing person before taking him to a hospital 2. Antiseptic - medicine to prevent infection. 3. Blisters - Bubbles on the burn. 1. What is first aid? 2. What are the things found in a first aid box? 3. Identify the following traffic signs Have a role play session in the class to demonstrate accidents and first aid given in each case. a. b. c. d. 142 Do this as group work. Make a first aid box. Each member can bring one item for the box. 4. Give 4 reasons for road accidents.

What is to be done when a. Someone gets a burn b. Someone is bitten by a wasp c. Someone gets injured d. Someone gets an electric shock. With permission from the concerned, examine the interior of an ambulance. How does it help to transport seriously injured people to the hospital without wastage of time? Write a short write up on “ambulance- timely help”. Make a first aid box. You may take help from elders. 143

Preservation of Food Protecting food items and food materials from being spoiled is called food preservation. Air, water and microbes are the main causes for spoilage of food. Ancient methods of food preservation In olden days, people used the following methods for preserving food. Some of them are in use even today. 1. Sun drying: Sun drying removes moisture from food and keeps it safe from decay. Examples are green mango, fish, bitter gourd, brinjal etc., Dates, grapes, tamarind are also dried and packed Mango jelly is also prepared by sun drying. 2. Salting: Keeping food in concentrated solution of salt prevents spoilage. Salt acts as a preservative. Mangoes and ginger are some food items that are preserved in this manner. 3. Keeping food items in sugar syrup: Fruits and some vegetables are preserved by keeping them in sugar syrup. Such preserved fruits are called morrabbas. Sugar is also a preservative. 4. Making Jam and Squashes: 144 Mixing fruits with sugar and cooking them till they become a thick paste helps to preserve fruits. This is called Jam. Fruit juice boiled with sugar into a syrup is called squash. It can be kept for many months.

5. Pickling : Vegetables can be pickled and kept for over a year without spoilage. Egyptians preserved dead bodies thousands of years ago using chemicals by a process called embalming . Such preserved dead bodies are called mummies . There is a mummy in the archeological museum in Hyderabad. Modern methods of food preservation 1. Pasteurization: This method was invented by Louis Pasteur. It is a method of protecting milk from spoilage. Milk gets spoiled by the action of bacteria. Bacteria do not survive at very high and very low temperatures. In order to protect milk from spoilage, it is first boiled to kill all the germs present in it. Then, it is immediately chilled, without allowing time for bacteria to enter it. This chilled milk doesn’t get spoiled if it is kept in a cool environment for over 2-3 days. Dairy farms use this method to keep milk from being spoilt. The chilled milk is packed in air tight containers or packets and sealed. 2. Canning: Fried and steamed food items are packed in air tight containers. In the absence of air, the chances of spoilage are practically nil. 3. Refrigeration: Refrigerators are a boon in the present day. In refrigerators, very low temperatures are maintained. At these low temperatures, microbes do not thrive. Chances of vegetables and fruits getting dried because of heat is also minimized in a refrigerator. They remain fresh for many days. 145 Pasteurization

4. Cold storage: In slaughter houses, there are cold storages to prevent meat from getting spoiled. In fisheries too, there are cold storages to keep fish fresh. Fish is usually kept with ice crystals to keep it frozen. In big hotels too, there are cold storages and chemical preservatives. In polar regions, people use natural refrigeration to preserve food items. They dig down into the ice and keep fish and meat in it and cover it with ice. Nowadays, packed or bottled fruit juices are available. They contain chemical preservatives like sodium benzoate in order to protect them from spoilage. 1. Syrup - a thick liquid formed when sugar is heated with minimum quantity of water. 2. Slaughter house - where animals like sheep, goat, cattle, and pig are butchered for meat. 3. Fisheries - where preservation and packing of fish are done for purposes of exporting. Fish products like cod liver oil, whale fat etc. are also made here. 4. Morabba - Pieces of fruits and vegetables like pumpkin, melon etc. kept in sugar syrup. They are covered by a coating of crystallized sugar. 146

1. In what ways can the following be preserved? Mention all the possible methods. a. Mango b. Fish c. Apple d. Meat e. Lemon f. Tomato g. Grapes h. Pineapple 2. What is pasteurization? 3. How is refrigeration helpful in preserving food items? 4. Mention the ancient methods of food preservation? 5. What is a cold storage? 6. Name a chemical preservative. • On the basis of your observation, write a short essay on \"can we eat frozen food items and ready to eat packaged food?\" • What is the significance of expiry date mentioned on the packets? 1. Why food items like vegetables kept in salt do not get spoiled? 2. Why fruits are made into squashes and jams? 3. Boiled vegetables are better for health than raw vegetables. Why? 4. In olden days, people used to dry vegetables, fruits, meat and fish in the sun. Why? 5. Why food items stored in airtight containers do not get spoiled? 6. What is the principle of refrigeration? 147

1. Visit a dairy or food processing unit if there are any in your area. Find out what are the milk products made and how they are preserved. If you visit a food processing unit, find out how different food items are preserved. 2. Visit a mall or supermarket. Study the writings on the squash, jam or pickle bottles. Note what preservatives they have used. Note down how milk is packed, Idly & dosa batter is preserved, and Study the mode of packaging and preservatives used in frozen meat and fish. Note down the expiry date of all the products. • Prepare a puppet show on good preservation. The grandmother puppet demonstrates the old methods, while the teacher puppet narrates the modern methods of preservation. • Specimens are to be displayed. • Puppets can be made with a cardboard attaching them to a stick; or a ball and glove. 148

Contents 1. Major Landforms of the Earth _ 150 2. Our Country - India _________ 158 3. Northern Mountains_________ 166 4. Deserts, Plains and Plateaus _ 172 5. Climates of India ___________ 179 6. Soil and Vegetation in India - Forest Wealth _____________ 186 7. Water Resources and Mineral Wealth of India ____________ 196 Class 4 Term 1

Major Landforms of the Earth Formation of different landforms The earth was formed about 4.5 billion years ago. In course of time, it underwent many changes. It took millions of years for earth to differentiate into three layers, as we see now - the crust, the mantle, and the core. Billions of years ago, i.e., after the differentiation the crust was mainly solidified rocky matter which seemed to float in a huge body of water. 150 Crust Mantle Outer core Inner core Earth core Physical map of the world