Congruence of triangles

The Chemical Rainbow-Acids and Bases

The Chemical Rainbow-Acids and Bases

->What is the use of sanitary cleaner like Harpic?

   To clean toilet/floor stains etc.

->Haven’t you been advised by your elders not to touch this liquid? Why?

Yes, because it harms the skin if it comes in contact with our skin.

Acids are substances which produce hydrogen ions when dissolved in water. ·

Hydrochloric acid (HCl) and   Sulphuric acid (H2SO4)  are strong acids.

 natural acids such as formic acid(HCOOH) and acetic acid (CH3COOH) are weak acids.

-> What will happen when base is dissolved in water?

It will produce hydroxide  ions .

->How you can identify if a substance is acid or base as it is hazardous to taste all chemicals?

By use of indicators.

Type of Indicator		Example
Natural indicator	Naturally occurring substances which act as indicators	Litmus, turmeric, red cabbage and china rose   .
Synthetic indicators	They are produced in the laboratory using chemicals	Phenolphthalein, methyl orange colour indicators
Olfactory indicators		Garlic

                                                                                                

Litmus: ® is one of the earliest known indicators and it is a natural dye obtained from lichens

              ® solution turns red when added to acid solution.

             ® solution turns blue when added to basic solution.

->  When acids dissolves in water which ions are formed.

       Hydrogen  ions

->  Give one example of strong base?

       Sodium hydroxide/ potassium hydroxide/ calcium hydroxide.

->What happens when red litmus paper is dissolved in base?

        Red litmus paper turns blue.

->What are indicators?

         Indicators are substances that changes their properties according to acidic or basic environment.

-> Give examples of natural indicators.

      litmus, china rose, turmeric

 -> What happens when you try to wash a turmeric stain on your clothes with soap?

    The stain turns red in colour.

-> When turmeric paper strip is dipped in the shampoo solution , the  colour  of turmeric paper strip changes to red,

   It indicates that shampoo solution is basic in nature.

 -> When turmeric paper strip is dipped in the cold drink , the colour of turmeric paper strip does not chang.

   Cold drink is acidic in nature.

-> Give any two examples of natural indicators.

Litmus/Turmeric/China rose

 -> Name one synthetic indicator?

Phenolphthalein is a colourless synthetic indicator. When it is added to

 an acidic solution, it remains colourless

 a basic solution ,it turns bright pink.

-> What is the colour obtained when universal indicator is added to hydrochloric acid?

Bright red

->What is the colour obtained when universal indicator is added to calcium hydroxide?

Violet

-> What is the neutralisation reaction?

->When an acid is mixed with base in a suitable quantity, the resulting solution is neither acidic nor basic is known as neutralization  reaction.

->What are the products formed in neutralisation reaction?

Salt and water

->What is the common name of sodium chloride?

     Common salt

->Where do we use sodium chloride in our daily life?

    It is used in food to add taste and it is also used as preservative.

-> What happen when you eat spicy or oily food?  

 we get acidity/heartburn

 -> What you do when you suffer from acidity?

Take medicine to feel better

-> What does this medicine do to control acidity?

It  neutralizes the excess of acid in our stomach.

-> Which acid is present in ant’s bite?

Formic acid

-> What should be added to treat a soil if it’s too basic in nature?

Compost or organic manure should be added to treat the soil if it’s too basic in nature.

Social Science- Civics- Media and Democracy

Media and Democracy

Question and Answers.

1. What is media? (Refers to all the different things that we use to communicate with others.)
2. Identify the two types of media on the basis of technology. ( Print media and electronic media)
3. What is mass media? (Media that is used to communicate to a large number of people is known as mass media)
4. What does public opinion refer to? (Public opinion refers to the view or opinions of certain sections of a large group of people in a community or a country, on a particular issue.)
5. What is public opinion? (When a group of people come together to project a similar view, it is known as public opinion.)
6. Analyse the relationship between technology and media. (The relationship of media and technology interdependent. Without technology media wouldn’t be what it is today)
7. When did print media come into existence? ( Pint media came into existence when Johannes Gutenberg invented the printing press)
8. Why is media important in democracy? (Media acts as a link between the people and those who govern them by communicating the viewpoints of both.)
9. Why are advertisements important? (Another way in which mass media makes money is by advertising. There are advertisements of cars, phones, clothes, chocolates, etc. Even the radio earns money through advertisements.)
10. What is the responsibility of the media in general? (Mass media should be independent and not be influenced by anything or anyone when presenting facts to the people. Media should neither reflect the opinion of the business houses that control it nor should it reflect its own business interests. )
11. Who reads khabar lahriya? (The newspaper reaches farmers, school teachers, panchayat members and women who have learnt to read and write.)

Congruence of Triangles

Treasure Beneath our feet

The Treasure Beneath our Feet

Q. How plants prepare their own food?

A. Through process called photosynthesis.

 Q. Where photosynthesis takes place in plants?

A. -In leaves and In green parts of plants.

 Q.What is the name of the part of the plant from where plants absorb water and minerals?

  A. Roots

 Q..How the food (which is made in leaves) and water.Which is absorbed by roots) in the plant is transported to different parts of the plants?

A.-Through transportation system.

Q. What is xylem?

A.Water and minerals absorbed by the roots travel up to the leaves via tube like tissues called xylem.

Q. What is meant by ascent of the sap?

A,The process of transportation of water through xylem is called ascent of the sap.

->Sandy soil does not hold water therefore the ball made up of sandy soil crumbles, clayey soil retains water and also its particles size are small, therefore the ball made up of clayey soil feels smooth and It retains the shape.

->-Loamy soil retains enough water and also it is a mixture of all three particles-sand, silt and clay therefore the ball made of this soil feels partly gritty and partly smooth.

Q. Which soil is considered to be the best for agriculture?

A.loamy soil

Q. Which soil is considered to be the best for constructing building materials?

A.Sandy soil

Q.Soil is considered to be the best for making the pots?

A.Clayey soil

Q. What are the main three types of particles in the soil?

A.Sand, clay and silt

Q. Which soil has largest size of particles?

A.Sandy soil

Q..Which soil has smallest size of particles?

A.Clayey soil

Q.How the concentration of larger or smaller particles present in the soil can affect the movement of the water in the soil?

A.Concentration of larger size particles will allow the water to flow easily through the soil, while the concentration of smaller size particles in the soil will slow down the water movement in the soil/

->Too much of acid produced in the stomach causes acidity.

Q.Causes of soil pollution: ®

Too much use of insecticides and pesticides during farming ®

 Allowing untreated sewage water to seep into the soil.

 Disposal of non-biodegradable substances like plastic bags on the soil.

                              Rivers of life

1.       What are the basic materials that are needed by all living beings to survive?

- Food, water and air.

2.       What happens to the food we eat?

-it gets digested into simple absorbable substances called as nutrients in the digestive system to               give us energy and the waste is expelled out.

3.       What happen to the air we breathe?

-Our lungs absorbs oxygen and give out carbon dioxide.

4.        Name the only vein which carries oxygen- rich blood?

 (pulmonary vein)

5.       What is the structure of heart?

-  It is hollow, muscular bag like organ, made up of powerful muscles and shape like upside down pear.              

6.       What is septum? (

-The heart is divided into left and right parts by a thick vertical muscular wall called septum.

   -   7.Which organ system in human beings is responsible for removal of majority of urea and uric               acid /  waste materials from the human body?

           -Human urinary system

      8. Why is the process of sweating important for us?

          -  It helps in maintaining body temperature.