Question 1: Why do we need to separate different components of a mixture? Give two examples.
Answer 1: Different components of a mixture are separated in order to either separate the un-required components from a mixture or sometimes, to separate more than one useful components from a mixture.
For example, grain purchased from shops can contain several impurities such as pieces of stone, husk, broken grains, etc. Thus, grain is separated from these impurities to make it edible.
Similarly, after preparing tea, we strain it to remove the used tea leaves from tea.
Question 2: What is winnowing? Where is it used?
Answer 2: Winnowing is the process of separation of the heavier components from the lighter components of a mixture by wind or by blowing air.
It is generally used by farmers to separate the lighter impurities such as husk particles from the heavier grains.
Q 3: How will you separate husk or dirt particles from a given sample of pulses before cooking?
A 3: The dirt particles that are present in the pulses are removed by washing the latter with water. Being heavier, the pulses settle down, while the dirt particles being lighter keep floating in water. This process is called sedimentation. The dirty water can be removed by the method of decantation, leaving the pulses at the bottom.
Question 4: What is sieving? Where is it used?
Answer 4: Sieving is the method of separation of fine particles from bigger particles by allowing the finer particles to pass through the holes of a sieve, leaving the bigger particles in the sieve itself.
It is generally used in homes to separate flour from impurities such as pieces of stone, stalk, and husk. It is also used at construction sites to separate sand from small stones.
Question 5: How will you separate sand and water from their mixture?
Answer 5: Sand is not soluble in water. Hence, the mixture of sand and water can be separated by two methods:
- Combination of sedimentation and decantation: As sand is insoluble and heavier than water, it settles down at the bottom of the container containing the mixture. This process is called sedimentation. After the process of sedimentation is complete, water is slowly transferred to another container and sand remains in the original container. This process is called decantation.
- Filtration: the mixture is poured on a strainer or a piece of cloth or a filter paper so that the water goes through the strainer and the sand remains on the strainer.
Question 6: Is it possible to separate sugar mixed with wheat flour? If yes, how will you do it?
Answer 6: Yes. It is possible to separate a mixture of sugar and wheat flour.
This can be done by the process of sieving. If the mixture of sugar and wheat flour is allowed to pass through a sieve, then the fine wheat flour particles would pass through the sieve, the sugar particles would be retained by the sieve.
Question 7: How would you obtain clear water from a sample of muddy water?
Answer 7: Clear water can be obtained from a sample of muddy water by the method of filtration. In this method, the sample of muddy water is poured through a cloth having fine pores or through a filter paper. Water will pass through the filtering medium, leaving behind the mud.
Question 8: Fill in the blanks:
(a) The method of separating seeds of paddy from its stalk is called ________.
(b) When milk is cooled after boiling and poured on a piece of cloth, cream (malai) is left behind on it. This process of separating cream from milk is an example of _________.
(c) Salt is obtained from seawater by the process of __________.
(d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. Clear water was then poured from top. The process of separation used in this example is called _________.
Answer 8: (a) The method of separating seeds of paddy from its stalk is called __threshing__.
(b) When milk is cooled after boiling and poured on a piece of cloth, cream (malai) is left behind on it. This process of separating cream from milk is an example of __filtration__.
(c) Salt is obtained from seawater by the process of __evaporation__.
(d) Impurities settled at the bottom when muddy water was kept overnight in a bucket. Clear water was then poured from top. The process of separation used in this example is called __decantation__.
Question 9: State whether the following statements are ‘True’ or ‘False’?
(a) A mixture of milk and water can be separated by filtration.
(b) A mixture of powdered salt and sugar can be separated by the process of winnowing.
(c) Separation of sugar from tea can be done through filtration.
(d) Grain and husk can be separated by the process of decantation.
Answer 8: (a) A mixture of milk and water can be separated by filtration. (False)
(b) A mixture of powdered salt and sugar can be separated by the process of winnowing. (False)
(c) Separation of sugar from tea can be done through filtration. (False)
(d) Grain and husk can be separated by the process of decantation. (False)
Tuesday, August 2, 2011
Answers of Science Class VI Test -1 From Chapter 2 – Components of Food
M.M: 57 marks
Time: 1 hour
A 1: Fill in the blanks (1 mark per question x 18 = 18 marks)
- Nutrients are the ingredients that contain some component needed by our body.
- The major nutrients in our food are carbohydrates, proteins, fats, vitamins and minerals.
- The main carbohydrates found in our food are the form of starch and sugars.
- While doing test for starch in a food item or raw ingredient, 2-3 drops of iodine solution is put in the item being tested.
- When test for starch in a food item is done, the blue-black colour is obtained.
- While doing test for fats in a food item, an oily patch on paper shows that the food item contains fat.
- The white portion of boiled egg will have proteins in it.
- Milk will have proteins and fats in it.
- Carbohydrates mainly provide energy to our body.
- Proteins are needed for the growth and repair of our body.
- Vitamins help in protecting our body against diseases.
- Names of two common vitamins are vitamin A and vitamin C.
- Vitamin A keeps our skin and eyes healthy.
- Mango, Papaya, Carrot, and Liver are rich in vitamin A.
- Lemon, Amla, Guava and Orange are rich in vitamin C.
- Rice is a carbohydrate rich source of food.
- Lack of vitamin A can cause loss of vision.
- Diseases that occur due to lack of nutrients over a long period are called deficiency diseases.
Q 2: In brief, write how will you do a test for protein in a food item? (3 marks)
A 2: Take a small quantity of a food item for testing. If the food item is a solid then make a paste of it by mashing it or powder it by grinding.
Take a clean glass test tube, add ten drops of water to the food item in the test tube and shake the test tube. Using a dropper, add two drops of solution of copper sulphate and ten drops of solution of caustic soda to the test tube.
Shake well and let the test tube content stand for a few minutes. A violet colour will indicate the presence of protein in the food item.
Q 3: Write two nutrients that provide us energy. (2 marks)
A 3: Fats and carbohydrates provide us energy.
Q 4: Foods containing which nutrient are called body building foods? (1 mark)
A 4: Foods containing proteins are called body building foods.
Q 5: What helps in keeping our eyes, bones, teeth and gums healthy? (1 mark)
A 5: Vitamins help in keeping our eyes, bones, teeth and gums healthy.
Q 6: Which vitamin helps our body to use calcium for bones and teeth? (1 mark)
A 6: Vitamin D helps our body to use calcium for bones and teeth.
Q 7: Write four sources of vitamin D. (2 marks)
A 7: Four sources of vitamin D are milk, butter, eggs and fish.
Other sources of vitamin D are Cereals, Cod liver oil, Mushrooms and Cheese. Natural source of vitamin D is Sunlight.
Q 8: Write four sources of vitamin B. (2 marks)
A 8: Four sources of vitamin B are liver, bananas, potatoes and green vegetables.
Other sources of vitamin B are eggs, dairy products, meat and liver.
Q 9: What do you understand by roughage? What is its use in our body? Which products in our foods provide roughage? (3 marks)
A 9: Roughage is dietary fibres. Roughage does not provide any nutrient to our body but is an essential component of our food as it helps in getting rid of undigested food in our body.
Q 10: In the given table, fill two sources of each of the minerals.
(4 marks)
A 10:
Sources of iodine
|
Garlic, Mushroom. Others are: Seafood, Soya beans, Spinach and Turnip.
|
Sources of phosphorus
|
Peanuts, Oats. Others are: barley, Raw cashew nuts, Sesame seeds and Black beans.
|
Sources of iron
|
Cooked spinach, green soya beans. Others are: Sorghum, coconut milk, raw cashew nuts and oats.
|
Sources of calcium
|
Green turnip and cooked spinach. Others are orange juice, soya milk.
|
Q 11: What are the two purpose of water in human body?
A 11: The two purpose of water in human body are:
- It helps our body to easily absorb nutrients from food.
- It helps in throwing out some wastes from our body through urine and sweat.
Q 12: Define balanced diet.
A 12: A balanced diet is a diet that has all the necessary nutrients needed by our body in right amount along with adequate quantity of water and roughage also.
Q 13: In the given table, complete the disorder column by filling the name of disorder and symptom column by filling one symptom for the corresponding lack of given vitamins/minerals.
A 13:
Deficiency of vitamin/mineral
|
Name of disorder
|
Symptoms
|
Iron
|
Anaemia
|
Weakness.
|
Calcium
|
Bone and tooth decay
|
Weak bones, tooth decay.
|
Vitamin D
|
Rickets
|
Bones become soft and bent.
|
Vitamin C
|
Scurvy
|
Bleeding gums, wound takes longer to heal.
|
Q 14: Deficiency of vitamin B1 causes which disorder and what are its two symptoms? (3 marks)
A 14: Deficiency of vitamin B1 causes Beriberi. The symptoms of Beriberi are:
- Weak muscles
- Very little energy available for work.
Q 15: Lack of iodine causes which disease and what are its two symptoms?
A 15: Lack of iodine causes Goiter or Goitre. Two symptoms of Goiter or Goitre are:
- Glands in the neck appear swollen
- Mental disability happens in children.
Q 16: What are the two symptoms of loss of vision disorder?
A 16: The two symptoms of loss of vision disorder are:
- Poor vision
- Loss of vision in night or darkness.
Q 17: Write True or False, Correct false statements wherever relevant. (1 mark x 5 = 5 marks)
A 17:
- Chips are good source of dietary fibre – False (Chips are junk food so they are not source of dietary fibre).
- Only some of the deficiency diseases can be prevented by taking a balanced diet – False (All deficiency diseases can be prevented by taking a balanced diet).
- Obesity means being too much thin – False (Obesity means being too fat).
- Vitamins and minerals are there on skins of many vegetables and minerals – True.
- Cooking results in loss of certain nutrients – True.
Thursday, July 28, 2011
CBSE Science Class 6 Model Paper From Chapter 11 - Light, Shadows and Reflection
M.M: 29 marks Date: 28/07/2011
Time: 40 minutes
Q 1: Fill in the blanks (1 mark per question x 11 = 11 marks)
- _________ objects do not allow light to pass through them.
- Light travels in a __________ line.
- Clear shadows are formed when an ________ object comes in the path of light.
- __________ objects allow light to pass through them partially.
- Objects having ability to produce their own light are called _____________ objects.
- The length of a shadow in daytime is smallest at _______ time.
- An image that cannot be obtained on a screen is called ___________ image.
- The left part of an object becomes _______ part when the object is seen in a plane mirror.
- An image formed at 2 m from the plane mirror will be _____ far from the object.
- The category of image formed in a cinema screen is ________.
- The category of image formed in standing clear water is ________.
Q 2: Choose the right answer: (1 mark)
A plane mirror forms an image which is:
- Inverted
- Real
- Enlarged
- Virtual
Q 3: Find the odd one out: (1 mark)
- Sun
- Stars
- Burning candle
- Moon
Q 4: What do you understand by rectilinear propagation of light? (1 mark)
Q 5: Why do we not see shadow of a plane flying very high in the sky? (1 mark)
Q 6: Write True or False, also write the correct statement wherever applicable for the false ones. (1 mark per question x 7 = 7 marks)
- A screen is not always needed for formation of a shadow - ________
- Shadows can never mislead about the shape of the object - _________
- Moon is an example of non-luminous object - _______________
- A firefly is a living source of light - _________
- The image formed by a pin hole camera is not inverted - __________
- Shadows and images are same - ___________
- Coating of mercury is done at the back of a glass to make it a mirror - ________
Q 7: With the help of an activity, prove that a plane mirror reflects light. (2 marks)
Q 8: In brief, describe the construction of a sliding pin hole camera with a diagram. (4 marks)
Q 9: Write two conditions that are necessary for an object to be visible to our eyes. (2 marks)
Q 10: What will happen if you try to see the flame of a burning candle through the following? (3 marks)
- Opaque object
- Translucent object
- Transparent object
Q 11: What is a periscope? Draw its diagram and explain its working in brief. (3 marks)
Q 12: Define light, shadow and reflection. (3 marks)
Wednesday, July 27, 2011
CBSE Class 6 Science Model Test Paper From Chapter 4 - Sorting Materials Into Groups
M.M: 30 marks Dated: 27/07/2011
Time: 40 minutes
Q 1: Why a tumbler is not made of paper or cloth? (1 mark)
Q 2: On what two criteria, do we choose a material for making an object? (2 marks)
Q 3: What do you understand by lustre? Name two substances that have lustre. (2 marks)
Q 4: When will you call a material hard and when will you call it soft? Give two examples each of hard material and soft material. (3 marks)
Q 5: What will happen when you mix water with (3 marks)
- Sand?
- Chalk powder?
- Sawdust?
Q 6: What do you understand by transparent, translucent and opaque material? Give two examples of each. (6 marks)
Q 7: Write two materials that float on water and two materials that do not float on water. (2 marks)
Q 8: Pick the odd one out from the given materials and explain the reason for picking it. (1 mark)
Sugar, Salt, Sand and Copper sulphate
Q 9: Give one example that shows that the property of oxygen mixing with water is useful? (1 mark)
Q 10: Write two liquids that are soluble in water and two liquids that are insoluble in water. (2 marks)
Q 11: Write two materials that are attracted by a magnet and two materials that are not. (2 marks)
Q 12: Write True or False for the given statements. Correct the false statements. (5 marks)
- A non glossy notebook has lustre while a new metallic spoon does not have lustre - __________
- Materials that allow heat to pass them are called insulators - _________
- Liquids that mix with water area called immiscible - ___________
- Clouds are an example of transparent material – __________
- Flour is soluble in water - __________
CBSE Science Class 6 Model Paper From Chapter 2 - Components Of Food
M.M: 57 marks Dated: 26/07/2011
Time: 1 hour
Q 1: Fill in the blanks (1 mark per question x 18 = 18 marks)
- _________ are the ingredients that contain some component needed by our body.
- The major nutrients in our food are ____________, __________, _______, _________ and __________.
- The main carbohydrates found in our food are the form of ______ and _________.
- While doing test for starch in a food item or raw ingredient, 2-3 drops of ________ solution is put in the item being tested.
- When test for starch in a food item is done, the ________ colour is obtained.
- While doing test for fats in a food item, an ______ patch on paper shows that the food item contains fat.
- The white portion of boiled egg will have ______ in it.
- Milk will have __________ and ________ in it.
- Carbohydrates mainly provide ________ to our body.
- Proteins are needed for the __________ and _______ of our body.
- _________ help in protecting our body against diseases.
- Names of two common vitamins are vitamin ____ and vitamin _____.
- Vitamin _____ keeps our skin and eyes healthy.
- Mango, Papaya, Carrot, and Liver are rich in vitamin ______.
- Lemon, Amla, Guava and Orange are rich in vitamin ______.
- Rice is a ________ rich source of food.
- Lack of vitamin ______ can cause loss of vision.
- Diseases that occur due to lack of nutrients over a long period are called __________ _____________.
Q 2: In brief, write how will you do a test for protein in a food item? (3 marks)
Q 3: Write two nutrients that provide us energy. (2 marks)
Q 4: Foods containing which nutrient are called body building foods? (1 mark)
Q 5: What helps in keeping our eyes, bones, teeth and gums healthy? (1 mark)
Q 6: Which vitamin helps our body to use calcium for bones and teeth? (1 mark)
Q 7: Write four sources of vitamin D. (2 marks)
Q 8: Write four sources of vitamin B. (2 marks)
Q 9: What do you understand by roughage? What is its use in our body? Which products in our foods provide roughage? (3 marks)
Q 10: In the given table, fill two sources of each of the minerals. (4 marks)
Sources of iodine
| |
Sources of phosphorus
| |
Sources of iron
| |
Sources of calcium
|
Q 11: What are the two purpose of water in human body? (2 marks)
Q 12: Define balanced diet. (1 mark)
Q 13: In the given table, complete the disorder column by filling the name of disorder and symptom column by filling one symptom for the corresponding lack of given vitamins/minerals. (4 marks)
Deficiency of vitamin/mineral
|
Name of disorder
|
Symptoms
|
Iron
| ||
Calcium
| ||
Vitamin D
| ||
Vitamin C
|
Q 14: Deficiency of vitamin B1 causes which disorder and what are its two symptoms? (3 marks)
Q 15: Lack of iodine causes which disease and what are its two symptoms? (3 marks)
Q 16: What are the two symptoms of loss of vision disorder? (2 marks)
Q 17: Write True or False, Correct false statements wherever relevant. (1 mark x 5 = 5 marks)
- Chips are good source of dietary fibre - _________
- Only some of the deficiency diseases can be prevented by taking a balanced diet - __________
- Obesity means being too much thin - __________
- Vitamins and minerals are there on skins of many vegetables and minerals - _________
- Cooking results in loss of certain nutrients - _________
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