CLASS 6TH SCIENCECH 12, 14 and 15

 Date: 7^th November 2022

Day: Monday

Ch 12: Electricity and Circuits

Keywords:

1. Conductors: Substance through which electricity and heat can pass.

2. Insulators: Substance through which heat and electricity cannot pass.

3. Switch: Device which can break or make the electric circuit

4. Terminal: point through which electric current enter or exit

5. Filament: Tungsten wire in the bulb which glow when electricity is passed through it.

Answer the following questions in 1-10 words

Q1. It is a device which glows to give light when electricity is passed through it.

Ans. Bulb

Q2. It is a circuit in which different appliances are connected and electric current can pass through it.

Ans. Electric circuit

Q3. It is small device in which chemical energy is stored which can be converted into the electric energy.

Ans. Electric cell.

Q4. Name terminals of the cell.

Ans.  Positive and negative terminals

Q5. How many terminals does a bulb have?

Ans. 2

Q6. Give four examples of conductors.

Ans. Iron, copper, gold, silver, zinc, aluminium etc.

Q7. Name some examples of insulators.

Ans. Wood, paper, plastic, rubber, glass etc.

Q8. Draw the symbol of the electric cell.

Ans.

Q9. What is the direction of flow of electric current in a circuit?

Ans. It flows from the positive terminal to the negative terminal of the cell.

Q10. What is the direction of flow of electrons in the electric circuit?

Ans. It flows from negative terminal to the positive terminal of the cell.

Answer the following questions in 20-25 words:

Q11. Explain why the bulb would not glow in the arrangement shown in the figure?

Diagram 6 lines

Ans. Bulb would not glow because tester used in the circuit is an insulator and electric current cannot pass through the insulator.

Q12. Complete the drawing shown in figure to indicate where the free ends of the wires should be joined to make the bulb glow.

Ans. 14 lines

Q13. What is the purpose of an electric switch? Name some electric gadgets that have switches built into them.

Ans. Electric switch make or break the electric circuit to switch on or off of an electric device. Gadgets such as television, radio, refrigerator, computers etc. have switches built into them.

Q14. Using the “ conduction tester” on an object it was found that the bulb begins to glow. Is that object a conductor or an insulator? Explain.

Ans. The object is a conductor because electric current can pass through conductors but not from an insulator.

Q15. Why should an electrician use rubber gloves while repairing an electric switch at your home? Explain.

Ans. Electrican use rubber gloves because rubber is an insulator and electric current cannot pass throght it. Hence, it prevents an electricial from getting electric shock.

Answer the following questions in 50-60 words

Q16. A). The handles of the tools like screwdrivers and pliers uses by the electricians for the repair work usually have plastic or rubber covers on them. Can you explain why?

B). Draw the symbols of electric wire, cell, battery, bulb, switch in on position, and switch in off position.

Ans. A) The handles of pliers and screwdrivers have covers of plastic and rubber because rubber and plastic are insulators and they prevent electricians from getting an electric shock.

B) The symbols of electric wire, cell, battery, bulb, switch in on position, and switch in off position are drawn below:

 

 

Date: 28 November 2022

Day: Monday

Chapter 14 Water

Keywords:

1. Condensation: Process of changing water vapour to water on cooling.

2. Drought: When there is no rain for a long time.

3. Groundwater: Water present under the Earth’s surface.

4. Ocean: Extremely large bodies of water.

5. Rainwater harvesting: Collecting rainwater for later use.

6. Water vapour: Gaseous form of water

7. Water cycle: The movement of water between the land and the atmosphere.

 

Answer the following questions in 1-10 words:

Q1. The cluster of water droplets at high altitude in the atmosphere.

Ans. Clouds

Q2. When the water level on the Earth’s surface increases due to heavy rain.

Ans. Floods

Q3. When ice falls in the form of small stones during rain.

Ans Hail

Q4. When ice falls in the form of an extremely tiny sphere in the cold region is called.

Ans. Snow

Q5. Why evaporation is faster plate as compared to the tumbler when an equal amount of water is placed in them?

Ans. This is because the area of evaporation is more in the plate as compared to the tumbler.

Q6. How much percentage of water is present under the Earth’s surface?

Ans. 1%

Q7. What are the sources of potable water?

Ans: Sources of potable water:

1. Rain    2. Groundwater 3. Rivers and lakes       4. Glaciers

Q8. What are the causes of floods and drought?

Ans. Heavy rain results in flood and no rain for a long time results in drought.

Q9. How rate of evaporation varies with the temperature?

Ans. The rate of evaporation increases with the increase in temperature.

Q10. Name the technique by which rainwater can be conserved.

Ans. Rainwater harvesting.

Answer the following questions in 30-40 words:

Q11. Suppose you want to dry your school uniform quickly. Would spreading it near an anghiti or heater help. If yes, how?

Ans: Yes, the school uniform will dry up quickly. This is because the temperature near the anghiti or heater is high. As a result, the evaporation rate will be more near the anghiti or the heater.

Q12. Take out a colled bottle of water from the refrigerator and keep it on a table. After some time you notice droplets of water around it. Why?

Ans. This is because the surface of the bottle has low temperature and water from the atmosphere condenses on it. Hence, the droplets of water appear on the outer surface of the bottle.

Q13.To clean their spectacles, people often breathe out on glasses to make them wet. Explain why glasses become wet.

Ans. When people breathe out on spectacles, they become wet because the air from the mouth is extremely humid and moisture from the mouth condenses on the glasses of spectacle. Hence, people breathe out on spectacles to make them wet to clean the glasses.

Q14. When does drought occur?

Ans. When there is no rain for a long time and soil becomes dry due to lack of water and this condition is called drought.

Q15. How are clouds?

Ans. 1. Sea water is evaporated by the Sun.

2. At high altitudes, water vapours condensed to form tiny droplets

3. These tiny droplets surround the dust or smoke particles

4. When tiny droplets of water make huge clusters are called clouds.

5. In this way, clouds are formed.

Answer the following questions in 50-60 words:

Q16. Explain the water cycle with the help of a diagram.

Ans. The water cycle is the movement of water between the land and the atmosphere. Sea water is evaporated by the Sun and plants do the transpiration. In this way, water moves into the atmosphere. When water vapours moves at high altitude, it condenses down to form tiny droplets and finally clouds. Clouds move from one place to another place and by the process of rain water comes back to land oceans. In this way, water moves between the land and the atmosphere.

 

Date: 8 December 2022

Day: Thursday

Ch 15: Air Around Us

Keywords

1. Atmosphere: The blanket of air around the Earth's surface.

2. Carbon dioxide: Gas in the atmosphere that plants use to do photosynthesis.

3. Composition of air: Constituents of air

4. Oxygen: Gas in the atmosphere that animals use to respire.

5. Nitrogen: Gas in the atmosphere which is a major component of amino acids and proteins.

 

Answer the following questions in 1-10 words:

Q1. What is a windmill?

Ans. A device which is used to convert wind energy to mechanical energy.

Q2. What is smoke?

Ans. Harmful gases or substances which emit on burning of something.

Q3. What is the composition of air?

Ans, 78% Nitrogen, 21% oxygen and 1% other gases.

Q4. Which gas is essential for burning?

Ans. Oxygen is essential for burning.

Q5. Which gas is used to extinguish fire?

Ans. Carbon dioxide

Q6. Name the gas which helps in the growth of the plant?

Ans. Nitrogen

Q7. Name the gas which is essential to respire?

Ans. Oxygen

Q8. Does dry soil has moisture?

Ans. Yes, dry soil contains moisture.

Q9. From where do aquatic animals get the oxygen?

Ans. They use oxygen dissolved in the water

Q10. Name the respiratory organ of the fish.

Ans. Gills

Answer the following questions in 30-40 words:

Q11. How will you show that air is dissolved in water?

Ans. 1. Take a 100 ml water in a container

2. Heat up the water.

3. The bubbles will appear in the container

4. These bubbles are filled with the water.

5. This shows that air is present in the water.

Q12. Why does a lump of cotton shrink in the water?

Ans. When a lump of cotton is immersed in water, the air present in the cotton is displaced by water and the size of the cotton lump reduces. Hence, a lump of cotton shrink in the water.

Q13. List five activities which is possible due to the presence of air.

Ans. 1. Respiration   2. Photosynthesis 3. Evaporation     4. Condensation

5. Transpiration      6. Flying of kite      7. Movement of leaves of tree

8. Falling of leaves of tree  9. Flying of birds 10. Dispersion of seeds  

11. pollination         12. Flying of aeroplane

Q14. How do plants and animals help each other in exchange of gases in the atmosphere?

Ans. Animals take oxygen from the atmosphere and release carbon dioxide in the atmosphere. This carbon dioxide gas is used by plants to do photosynthesis and they release oxygen gas in the atmosphere. In this way, plants and animals help each other in exchange of gases in the atmosphere.

Q15. What is windmill? How it generates electricity?

Ans. Windmill is a device which is used to convert wind energy to mechanical energy. The shaft of the windmill is connected to the electric generator and electric generator converts the mechanical energy into the electric energy.

Answer the following questions in 50-60 words

Q16. How will you prove that air supports burning?

Ans.1. Take a candle and burn it.

2. Now take a tumbler and place it on the candle by inverting it.

3. Wait for 15-20 seconds

4. The candle will extinguish.

5. The candle blow out because we have cut the supply of the air by placing a inverted tumbler on the candle.

6. This shows that air is required for burning.