Understanding Types of Changes: Physical, Chemical, Temporary, and Permanent

Explore the fascinating world of changes in materials. Learn about physical and chemical changes, temporary and permanent changes, and how heating causes transformations in everyday substances.

Introduction

Changes are an integral part of our daily lives. From the water boiling in your kettle to the rust forming on an old bike, changes in materials surround us. These changes can be categorized into various types, including physical and chemical changes, and further into temporary and permanent changes. Understanding these transformations is crucial for comprehending the nature of substances and their interactions. This blog will delve into the different types of changes, including the impacts of heating, and provide examples of temporary changes in everyday life.

Types of Changes: Physical and Chemical

Chemical reactions are often referred to as permanent changes. In the context of changes in matter, there are two main types: physical changes and chemical changes.

1.         Physical Changes (Temporary Changes): These involve alterations in the physical state or appearance of a substance without changing its chemical composition. Examples include changes in state (solid to liquid to gas) or changes in shape. Physical changes are usually reversible, meaning the substance can return to its original state.

2.         Chemical Changes (Permanent Changes): These involve the transformation of substances into new substances with different chemical compositions. Chemical changes are often irreversible, meaning the original substances cannot be easily recovered. During a chemical reaction, bonds between atoms are broken and new bonds are formed, resulting in the creation of entirely new substances.

So, when people talk about “permanent changes,” they are often referring to chemical changes because these alterations are typically not easily reversed. In the context of chemical reactions, the terms “chemical changes” and “permanent changes” are often used interchangeably.

Temporary and Permanent Changes to Materials

Temporary (Physical) and Permanent (Chemical) Changes Demonstrate temporary (physical) change: In this activity you will investigate what happens to a piece of fat placed on a hot saucer. demonstrate permanent (chemical) change  In this activity you are required to investigate what happens to a piece of wood when burnt in air.

Temporary (Physical) and Permanent (Chemical) Changes

Changes to materials can be broadly categorized into temporary (physical) changes and permanent (chemical) changes. Understanding these distinctions is fundamental to chemistry. Physical changes involve alterations in the state or appearance of a substance without changing its chemical composition. On the other hand, chemical changes result in the formation of new substances with different properties.

Explanation:

Temporary (Physical) Changes: Temporary changes are those where the substance undergoes alterations in its physical state or appearance, but its chemical composition remains unchanged. An example of a temporary change can be demonstrated by investigating the behavior of fat when exposed to heat. Heating fat causes it to melt, changing from a solid to a liquid state. However, the chemical composition of the fat remains the same—it is still fat. Upon cooling, the fat will solidify again, illustrating the reversible nature of this physical change.

Permanent (Chemical) Changes: Permanent changes involve the transformation of substances into new ones with different chemical compositions. To demonstrate a permanent change, investigate the burning of wood in air. The combustion of wood is a chemical change where the wood reacts with oxygen to produce carbon dioxide, water vapor, and other by-products. The resulting ash is not the same as the original wood and cannot be reversed back into wood. This irreversible alteration is characteristic of chemical changes.

In conclusion, understanding the distinction between temporary (physical) and permanent (chemical) changes is crucial in the study of materials. Physical changes involve alterations in the physical state or appearance of a substance without changing its chemical identity, and they are reversible. On the other hand, chemical changes result in the formation of new substances with different properties, and these changes are typically irreversible. The investigation of fat melting and wood burning serves as practical examples to illustrate these concepts. Recognizing and manipulating these changes are fundamental to various scientific and industrial processes.

Activity: demonstrate  physical change

do a procedure on how to Demonstrate temporary (physical) change: In this activity you will investigate what happens to a piece of fat placed on a hot saucer. demonstrate permanent (chemical) change  In this activity you are required to investigate what happens to a piece of wood when burnt in air.

Procedure: Demonstrating Temporary (Physical) and Permanent (Chemical) Changes

Materials Needed:

1.         A small piece of fat (butter or lard)

2.         Hot saucer or heating plate

3.         Candle or matchstick

4.         Piece of wood (small twig or a thin wooden stick)

5.         Fireproof surface or container

6.         Safety goggles

Demonstrating Temporary (Physical) Change: Melting Fat

1.         Safety First:

•          Put on safety goggles to protect your eyes.

2.         Prepare the Hot Saucer:

•          Heat the saucer or heating plate until it is hot. Use caution while handling hot surfaces.

3.         Place Fat on the Hot Saucer:

•          Carefully place a small piece of fat (butter or lard) onto the hot saucer. Observe what happens.

4.         Observe Melting:

•          Watch as the fat begins to melt due to the heat. Observe any changes in its state.

5.         Remove from Heat:

•          Once the fat has melted, remove the saucer from the heat source. Observe what happens as the fat cools down.

6.         Record Observations:

•          Record your observations, noting the changes in the fat during the heating and cooling processes.

Demonstrating Permanent (Chemical) Change: Burning Wood

1.         Safety First:

•          Ensure you are in a well-ventilated area, and put on safety goggles.

2.         Prepare the Fireproof Surface:

•          Place the fireproof surface or container in a safe location.

3.         Ignite the Wood:

•          Ignite one end of the piece of wood using a candle or matchstick.

4.         Observe Combustion:

•          Observe the wood as it burns. Pay attention to the changes in color, the production of flame, and any sounds.

5.         Continue Burning:

•          Allow the wood to burn completely. Note any changes in the appearance of the wood during combustion.

6.         Examine Residue:

•          After the wood has burned, examine the residue (ash) left behind.

7.         Record Observations:

•          Record your observations, noting the changes in the wood during the burning process and the characteristics of the residue.

Conclusion:

•          Compare and contrast the observations from both activities. Discuss the reversibility of the changes observed in melting fat (temporary change) and the irreversibility of the changes observed in burning wood (permanent change). This practical demonstration illustrates the concepts of temporary (physical) and permanent (chemical) changes in materials.

 Changing Substances

Let’s delve into   the understanding change, examples of changes which occur naturally in everyday life and What kinds of changes can be caused by heating.

Understanding Change

In a broad sense, change refers to the process or result of something becoming different. In the context of substances, change can involve alterations in their physical state, composition, or properties. Changes are pervasive in nature and can occur through various mechanisms, contributing to the dynamic nature of the world around us.

Examples of Changes Occurring Naturally in Everyday Life:

1.         Melting Ice:

•          As the temperature rises, ice (solid) changes to water (liquid).

2.         Ripening of Fruit:

•          Green bananas turning yellow as they ripen is a natural change associated with biochemical processes.

3.         Changing Seasons:

•          The transition from winter to spring involves changes in temperature, vegetation, and daylight hours.

4.         Growing Plants:

•          The growth of a seed into a plant involves a series of natural changes in size, structure, and function.

5.         Aging:

•          The gradual changes in a person’s physical appearance and capabilities over time.

6.         Day and Night:

•          The alternation between day and night is a natural change caused by the rotation of the Earth.

7.         Digestion of Food:

•          Food undergoing digestion in the human body represents a series of chemical changes.

Changes Caused by Heating:

1.         Melting:

•          Heating a solid can cause it to change into a liquid. For example, melting ice to form water.

2.         Evaporation:

•          The application of heat can lead to the evaporation of liquids, changing them into vapor. Boiling water is an example.

3.         Expansion:

•          Heating substances generally causes them to expand. This is evident in the expansion of metals when heated.

4.         Chemical Reactions:

•          Heating can initiate chemical changes. For instance, heating iron in the presence of oxygen leads to the formation of rust.

5.         Cooking Food:

•          Applying heat during cooking causes various changes in the chemical composition and structure of food.

6.         Sublimation:

•          Some substances can undergo sublimation, changing directly from a solid to a gas when heated. Dry ice (solid carbon dioxide) is an example.

7.         Thermal Decomposition:

•          Heating certain compounds can cause them to undergo thermal decomposition, breaking down into simpler substances. An example is the decomposition of limestone to produce lime and carbon dioxide.

Understanding the different types of changes and their causes is fundamental in various scientific disciplines, including chemistry and physics. It allows us to comprehend the natural processes and phenomena that shape the world we live in.

Temporary changes in everyday life

Examples of Temporary Changes in Everyday Life, Especially in the Kitchen:

1.         Melting Ice Cubes:

•          Placing ice cubes in a drink, which then melt over time, is a temporary change.

2.         Butter Softening:

•          Leaving a stick of butter at room temperature to soften is a temporary change in its state.

3.         Bread Toasting:

•          Toasting bread causes a temporary change in its texture and color without altering its chemical composition.

4.         Boiling Water:

•          Boiling water on the stove is a temporary change from liquid to gas (steam).

5.         Whipping Cream:

•          Whipping cream to create whipped cream is a temporary change in its texture and volume.

6.         Frying an Egg:

•          Cooking an egg in a pan involves a temporary change in the egg’s state from liquid to solid.

7.         Brewing Tea:

•          Steeping tea leaves in hot water is a temporary change, extracting flavors and colors from the leaves.

8.         Sugar Dissolving:

•          Stirring sugar into a cup of hot coffee causes a temporary change as the sugar dissolves.

9.         Chocolate Melting:

•          Melting chocolate in a microwave or over a double boiler is a temporary change in its state.

10.       Softening Vegetables:

•          Cooking vegetables in a pot results in a temporary change as they soften through the application of heat.

11.       Thawing Frozen Food:

•          Allowing frozen food to thaw at room temperature is a temporary change in its state.

12.       Whisking Egg Whites:

•          Whisking egg whites to create peaks is a temporary change in their structure.

13.       Creaming Butter and Sugar:

•          Creaming butter and sugar together during baking is a temporary change in their consistency.

14.       Condensation on a Cold Surface:

•          When a cold glass is placed in a warm environment, condensation is a temporary change on the glass surface.

15.       Whipping Egg Yolks:

•          Whipping egg yolks for recipes like mayonnaise involves a temporary change in their texture.

These examples illustrate how various temporary changes occur in everyday kitchen activities, highlighting the dynamic nature of materials and their responses to different conditions.

Conclusion

Understanding the different types of changes that materials undergo is essential for grasping the nature of substances and their interactions. Physical and chemical changes, temporary and permanent changes, and the effects of heating all play significant roles in our everyday experiences and industrial processes. By recognizing these changes, we can better appreciate the dynamic world around us and apply this knowledge in practical ways.

FAQs on physical and chemical changes

1. What is the difference between physical and chemical changes?
   • Physical changes alter the physical properties of a substance without changing its chemical composition, while chemical changes result in the formation of new substances with different properties.
2. Can physical changes be reversed?
   • Yes, physical changes are often reversible. For example, ice can melt into water and then be refrozen into ice.
3. What are some examples of chemical changes?
   • Examples of chemical changes include rusting of iron, burning of wood, and baking a cake.
4. What distinguishes temporary changes from permanent changes?
   • Temporary changes can be reversed, returning the material to its original state, while permanent changes result in new materials that cannot easily revert to their original form.
5. How does heating cause changes in substances?
   • Heating can cause both physical changes, such as changing states of matter (e.g., melting ice), and chemical changes, such as inducing reactions that form new substances (e.g., baking a cake).
6. What are some common temporary changes in everyday life?
   • Common temporary changes include condensation of water vapor, evaporation of water, and dissolving of sugar in tea.
7. Why are chemical changes usually irreversible?
   • Chemical changes involve the formation of new substances with different chemical compositions, making it difficult to revert to the original materials.
8. What happens during the rusting of iron?
   • During rusting, iron reacts with oxygen and moisture in the air to form iron oxide, a new substance.
9. Can you give an example of a permanent change caused by heating?
   • Baking a cake is a permanent change caused by heating, as the ingredients undergo chemical reactions to form a new product.
10. What role does heat play in physical changes?
    • Heat can cause physical changes by providing the energy needed for substances to change state, such as melting, boiling, or freezing.