CHANGES AROUND US

THIS PPT IS MADE BY SARA YADAV. PLS LIKE AND SHARE IF YOU FIND IT HELPFUL.

1. ℂℍ𝔸ℕ𝔾𝔼𝕊 𝔸ℝ𝕆𝕌ℕ𝔻 𝕌𝕊 𝕊𝔸ℝ𝔸 𝕐𝔸𝔻𝔸𝕍, 8𝔸

2. 𝕎ℍ𝔸𝕋 𝔸ℝ𝔼 ℂℍ𝔸ℕ𝔾𝔼𝕊? A change is the transformation of a substance from one form to another. A change may alter the physical or chemical or both properties of the substance. Different types of changes occur around us. Changes may be natural or man made , desirable or undesirable , reversible or irreversible , slow or fast , periodic or non-periodic , physical or chemical and exothermic or endothermic . Changes occur all around us, from in the morning while brushing to making food. Let us see 10 changes that occur in our daily life:

3. 1 .𝔽ℝ𝔼𝔼ℤ𝕀ℕ𝔾 𝕆𝔽 𝕎𝔸𝕋𝔼ℝ Keep water in the refrigerator for a couple of hours, the water will turn to ice. This is called freezing. Freezing is the process by which a substance changes from the liquid state to the to the solid state on cooling. As no new substance is formed, freezing is a PHYSICAL CHANGE Water changes to ice on cooling, therefore releasing heat. Thus, freezing is an EXOTHERMIC CHANGE . As freezing water to ice is use in cold drinks and for making ghee, Freezing is a DESIRABLE CHANGE. We can convert ice back to water by melting, thus Freezing is a REVERSIBLE CHANGE .

4. 2. ℂ𝕌ℝ𝔻𝕃𝕀ℕ𝔾 𝕆𝔽 𝕄𝕀𝕃𝕂 If you add lime juice or vinegar in milk, the milk changes into curd. Curd  is a  dairy product  obtained by  coagulating   milk which increases acidity and causes the milk proteins to tangle into solid masses, or curds.  Curdling is the process by which a liquid changes into a soft, semi solid mass. A new substance is formed that is a curd which has a new chemical composition, therefore Curdling is a CHEMICAL CHANGE. As curd cannot be converted back to milk , it is a IRREVERSIBLE CHANGE. The curdling of milk is used to make cheese, thus, curdling is a DESIRABLE CHANGE. During curdling, heat is absorbed , therefore Curdling is an ENDOTHERMIC CHANGE

5. 3. 𝔹𝕆𝕀𝕃𝕀ℕ𝔾 𝕆𝔽 𝕄𝕀𝕃𝕂 Boiling is the process by which a substance, when heated to its boiling point, changes from the liquid state at a particular temperature called the boiling point. As no new substance is formed, Boiling is a PHYSICAL CHANGE. Boiling water kills germs, thus Boiling is a DESIRABLE CHANGE. Boiling is an IRREVERSIBLE CHANGE. Boiling is a fast an man made change . Energy is absorbed during boiling, therefore it is an ENDOTHERMIC CHANGE.

6. 4. ℂ𝕆𝕆𝕂𝕀ℕ𝔾 𝕆𝔽 𝔽𝕆𝕆𝔻 Cooking is the process of producing safe and edible food by preparing and combining ingredients, and (in most cases) applying heat.   A new substance is formed, therefore cooking is a CHEMICAL CHANGE. After Cooking, food cannot be changed back to the Raw materials, thus , cooking is an IRREVERSIBLE CHANGE . It is a slow and man made change. Energy is absorbed during cooking, thus, cooking is an ENDOTHERMIC CHANGE.

7. 5. 𝕊𝕌𝔹𝕃𝕀𝕄𝔸𝕋𝕀𝕆ℕ 𝕆𝔽 ℕ𝔸ℙℍ𝕋ℍ𝔸𝕃𝔼ℕ𝔼 𝔹𝔸𝕃𝕃𝕊 Sublimation is the process by which a substance changes from the soild state to the gaseous state directly without forming the liquid state with absorption of heat. As no new substance is formed, Sublimation is a PHYSICAL CHANGE The sublimation of Naphthalene Balls results in the killing of pests, therefore it is a DESIRABLE CHANGE. Sublimation is a slow and irreversible change.

8. 6. 𝔻𝕀𝔾𝔼𝕊𝕋𝕀𝕆ℕ 𝕆𝔽 𝔽𝕆𝕆𝔻 Digestion is the process by which food is broken down into simple form that can be absorbed by the body by absorbing heat. As a new substance is formed, Digestion is a CHEMICAL CHANGE. Digestion is a DESIRABLE CHANGE as this process is required by the body. The food digested cannot be converted back to what it was, therefore Digestion is an IRREVERSIBLE CHANGE. As heat is absorbed during this process, Digestion is an ENDOTHERMIC CHANGE.

9. 7. ℂ𝕆ℕ𝔻𝔼ℕ𝕊𝔸𝕋𝕀𝕆ℕ 𝕆𝔽 𝕎𝔸𝕋𝔼ℝ 𝔻ℝ𝕆ℙ𝕃𝔼𝕋𝕊 𝕆ℕ 𝕋ℍ𝔼 𝔹𝔸𝕋ℍℝ𝕆𝕆𝕄 𝕄𝕀ℝℝ𝕆ℝ 𝔸𝔽𝕋𝔼ℝ 𝔸 ℍ𝕆𝕋 𝕊ℍ𝕆𝕎𝔼ℝ Condensation is a process by which a substance changes from gaseous state to the liquid state on cooling. As no new substance is formed, Condensation is a PHYSICAL CHANGE. Condensation , in this case is an UNDESIRABLE CHANGE. As this process can reversed on heating , Condensation is a REVERSIBLE CHANGE. Heat is released in this process, therefore Condensation is an EXOTHERMIC CHANGE.

10. 8. ℝ𝕌𝕊𝕋𝕀ℕ𝔾 𝕆𝔽 𝕀ℝ𝕆ℕ ℕ𝔸𝕀𝕃𝕊 Rusting is a process by which iron(Fe) changes to iron oxide (Fe2O3) when exposed to oxygen and moisture in the air. A new substance is formed, therefore Rusting is a CHEMICAL CHANGE. This process cannot be reversed, thus it is an IRREVERSIBLE CHANGE. Rusting is an UNDESIRABLE CHANGE as it weakens the Iron. Rusting is an EXOTHERMIC CHANGE as heat is released in this process.

11. 9. 𝔻𝕀𝕊𝕊𝕆𝕃𝕍𝕀ℕ𝔾 𝕆𝔽 𝕊𝕌𝔾𝔸ℝ 𝕀ℕ 𝕎𝔸𝕋𝔼ℝ 𝔽𝕆ℝ 𝕄𝔸𝕂𝕀ℕ𝔾 𝕁𝕌𝕀ℂ𝔼 The process of mixing a solid, liquid, or gas uniformly with another substance, mainly a solvent. As no new substance is formed, Dissolving is a PHYSICAL CHANGE. As Dissolving is used in making juice, it is a DESIRABLE CHANGE. Dissolving can be reversed, thus it is an REVERSIBLE CHANGE . This process absorbs heat, therefore it is an ENDOTHERMIC CHANGE.

12. 10. 𝔹𝕌ℝℕ𝕀ℕ𝔾 𝕆𝔽 ℂ𝔸ℕ𝔻𝕃𝔼 Burning is a process in which a substance combines with Oxygen at a high temperature, releasing heat and light. As a new substance is formed, Burning is a CHEMICAL CHANGE. It is an IRREVERSIBLE and FAST change. In this case, Burning is a DESIRABLE CHANGE as a burning candle gives us light. In this chemical process, heat is released,therefore it is an EXOTHERMIC CHANGE.

13. 𝓣𝓱𝓪𝓷𝓴 𝓨𝓸𝓾 𝓒𝓱𝓮𝓶𝓲𝓼𝓽𝓻𝔂 𝓗𝓸𝓵𝓲𝓭𝓪𝔂 𝓗𝓸𝓶𝓮𝔀𝓸𝓻𝓴