Lesson Notes By Weeks and Term v3 - Primary 4
Changes in Nature
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Changes in Nature
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Subject: Basic Science
Class: Primary 4
Term: 1st Term
Week: 1
Theme: Learning About Our Environment
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Watch on YouTubeSee Facebook poststate the meaning of change mention the changesthey observe in the irsurrounding state the differencesbetween temporary and permanent changes give examples of temporary and permanent changes
A. Meaning of Change Change refers to a process where something transforms from one state or form to another. It involves an alteration in appearance, composition, size, shape, or properties of an object or substance. Changes are happening all around us, all the time. For instance, a child grows into an adult, water turns into ice, or firewood burns to ash.
B. Types of Changes Changes can be broadly classified into two main categories: Temporary Changes and Permanent Changes.
1. Temporary Changes Definition: A temporary change is a type of change where a substance alters its physical state, shape, or form but does not form a new substance. The original substance can be recovered or returned to its initial state by reversing the conditions that caused the change. These changes are often physical changes.
Characteristics: No new substance is formed. The change is reversible (can be undone). The chemical composition of the substance remains the same. Often involves changes in state (solid to liquid, liquid to gas) or shape.
Examples (Nigerian Context): Melting of Ice: An ice block (solid water) left in the sun turns into water (liquid). If the liquid water is cooled sufficiently (e.g., put back in a freezer), it will turn back into ice. No new substance is formed; it's still water. (Think of ice block sellers).
Dissolving Sugar/Salt in Water: When sugar or salt is stirred into water, it seems to disappear.
However, if the water is evaporated, the sugar or salt can be recovered. The sugar/salt is still sugar/salt, and the water is still water.
Folding a Piece of Paper: Folding paper changes its shape, but it is still paper and can be unfolded back to its original flat form.
Bending a Wire: A metal wire can be bent into different shapes, but it remains a metal wire and can be straightened again.
Drying of Wet Clothes: Wet clothes left in the sun lose water and become dry. The water evaporates, but the fabric of the clothes remains the same. This is a common sight in Nigerian homes.
Boiling Water: Water boils and turns into steam (water vapour), but it is still water. When the steam cools, it condenses back into liquid water.
2. Permanent Changes Definition: A permanent change (also known as an irreversible change or chemical change) is a type of change where a substance transforms into one or more new substances with different properties. The original substance cannot be easily recovered, or it's impossible to return it to its initial state.
Characteristics: One or more new substances with different properties are formed. The change is irreversible (cannot be undone easily). The chemical composition of the substance changes. Often accompanied by release or absorption of energy (heat, light, sound).
Examples (Nigerian Context): Burning of Wood/Paper/Firewood: When wood or paper is burnt, it turns into ash and smoke. Ash is a completely new substance different from wood or paper. It is impossible to turn ash back into wood or paper. (Think of cooking with firewood or burning refuse). Cooking of Food (e.g., Frying an Egg, Boiling Yam, Baking Bread): When an egg is fried, its liquid protein changes into a solid. A boiled yam becomes soft and changes in texture and taste. These cooked items cannot be turned back into their raw state.
Rusting of Iron: When iron (like a nail, metal roof, or gate) is exposed to air and moisture for a long time, it forms a reddish-brown flaky substance called rust. Rust is a new substance (iron oxide) and cannot be easily changed back to iron. (Common on old zinc roofs or metal gates). Ripening of Fruits (e.g., Banana, Mango, Plantain): A green, unripe fruit changes colour, softens, and becomes sweeter as it ripens. This is a permanent change as the fruit cannot revert to its unripe state. * Growth of Plants and Animals: A seed grows into a seedling and then a mature plant. A baby grows into an adult. These are irreversible processes where new cells are formed, called rust. Rust is a new substance (iron oxide) and cannot be easily changed back to iron. (Common on old zinc roofs or metal gates). Ripening of Fruits (e.g., Banana, Mango, Plantain): A green, unripe fruit changes colour, softens, and becomes sweeter as it ripens. This is a permanent change as the fruit cannot revert to its unripe state.
Growth of Plants and Animals: A seed grows into a seedling and then a mature plant. A baby grows into an adult. These are irreversible processes where new cells are formed, and the organism fundamentally changes. * Souring of Milk: When milk sours, it changes in taste, smell, and texture due to bacterial action. It cannot be easily reversed to fresh milk. C. Differences Between Temporary and Permanent Changes | Feature | Temporary Change | Permanent Change | | :------------------- | :-------------------------------------------------- | :-------------------------------------------------- | | Reversibility | Reversible (can be returned to original state) | Irreversible (cannot be returned to original state) | | New Substance | No new substance is formed | New substance(s) with different properties are formed | | Composition | Chemical composition remains the same | Chemical composition changes | | Nature of Change | Usually a physical change (state, shape, size) | Usually a chemical change | | Examples | Melting ice, folding paper, dissolving sugar, drying clothes | Burning wood, cooking food, rusting iron, ripening fruit | Materials: Ice cubes, water, clear glass, sugar, spoon, paper, matchbox (for teacher use only, with extreme caution), small piece of wood/leaf, a rusty nail, a raw egg, a cooked egg, fresh and ripe fruit (e.g., banana, mango), a piece of wire, a wet cloth.
A. Introduction (5 minutes)
Teacher Activity: Begin by asking students what they observe happening around them daily. For example, "What happens when you leave an ice cream in the sun?" or "What happens to firewood when it's used for cooking?" Encourage a few responses. Introduce the topic "Changes in Nature" by explaining that everything around us is always changing.
Student Activity: Students share observations and answer simple questions, connecting to their experiences.
B. Meaning of Change and Observation of Changes (10 minutes)
Teacher Activity: Define "change" as "when something becomes different." Ask students to look around the classroom and mention any changes they notice or know about. (e.g., "The chalk has become smaller," "The plant in the corner has grown taller," "The water in the bucket looks different from when it was fetched"). Guide them to understand that these transformations are examples of change.
Student Activity: Students observe their surroundings and verbalize changes they identify.
C. Exploring Temporary Changes (15 minutes)
Teacher Activity:
1. Melting Ice: Place an ice cube in a clear glass of water or on a plate. Ask students to observe what happens over a few minutes. Explain that the ice (solid water) turned into water (liquid water). Discuss if it's possible to turn the liquid water back into ice (by freezing). Emphasize that no new substance was formed.
2. Dissolving Sugar: Put a spoon of sugar into another glass of water and stir. Ask students what happened to the sugar. Discuss that it seems to disappear but can be recovered (though not demonstrated for time) and that it is still sugar.
3. Folding Paper/Bending Wire: Fold a piece of paper and then unfold it. Bend a piece of wire and then straighten it. Explain that the shape changed, but the material remained the same and can be returned to its original form.
4. Drying Wet Cloth: Show a wet cloth and ask what happens if it's left outside under the sun. Explain that the water evaporates, and the cloth becomes dry, but the cloth itself remains the same.
Student Activity: Students observe the demonstrations, discuss their observations, and answer questions about the reversibility of the changes. They can physically fold paper or bend a piece of string/leaf.
D. Exploring Permanent Changes (15 minutes)
Teacher Activity:
1. Burning (with extreme caution, teacher only): Take a small, dry leaf or a tiny piece of paper and carefully burn it over a non-flammable surface (e.g., a metal tray). Show the ash produced. Ask if the ash can be turned back into the leaf/paper. Emphasize that a new substance (ash) has been formed.
2. Rusting: Show a rusty nail and a new, shiny nail. Explain that the rust is a new substance formed from the iron of the nail. Ask if the rust can be easily turned back into shiny iron.
3. Cooking Food: Show a raw egg and a fried/boiled egg. Explain that cooking changes the egg permanently; it cannot go back to being raw. Similarly, show a raw yam and mention what happens after it's boiled or fried.
4. Ripening Fruit: Show a green (unripe) banana/mango and a ripe one. Explain that the fruit changed colour, taste, and texture permanently.
Student Activity: Students observe the demonstrations (especially the burning from a safe distance), discuss the irreversibility of the changes, and identify the new substances formed.
E. Differentiating Between Temporary and Permanent Changes (10 minutes)
Teacher Activity: Facilitate a class discussion to compare and contrast the observed temporary and permanent changes. Use a simple T-chart on the board to list characteristics: "Can it go back?" "Is it a new thing?" Student Activity: Students contribute to the comparison, sharing their understanding and helping to build the T-chart with examples.
F. Conclusion and Review (5 minutes) * Teacher Activity: Briefly review the definitions of change, temporary change, and permanent of the changes, and identify the new substances formed.
E. Differentiating Between Temporary and Permanent Changes (10 minutes)
Teacher Activity: Facilitate a class discussion to compare and contrast the observed temporary and permanent changes. Use a simple T-chart on the board to list characteristics: "Can it go back?" "Is it a new thing?" Student Activity: Students contribute to the comparison, sharing their understanding and helping to build the T-chart with examples.
F. Conclusion and Review (5 minutes)
Teacher Activity: Briefly review the definitions of change, temporary change, and permanent change, asking students to recall examples for each. Reiterate that changes are constant in nature.
Student Activity: Students answer recap questions and confirm their understanding.
Food Preparation and Preservation in Nigerian Homes: Application: Students can relate the concept of permanent change to various cooking methods. Frying plantain, boiling yam, baking puff-puff, or making bean cake (akara) are all examples of permanent changes where raw ingredients are transformed into new, edible substances that cannot be reversed. This also extends to food preservation, where drying fish or maize (temporary change of water removal) or processing palm oil (permanent change) are vital practices in Nigerian communities.
Integration: Discussions can involve how families cook daily and why certain foods spoil (permanent change) and others are preserved.
Agriculture and Environmental Observation: Application: The growth of crops from seeds (e.g., maize, cassava, yam) to mature plants and then to harvest is a clear example of permanent change. The drying of harvested crops (e.g., maize, groundnut, cocoa beans) under the sun is a temporary change (removal of water). Students can observe these changes in local farms or markets. The effect of rain and sun on mud houses or unpainted metal roofs (rusting is a permanent change) also provides context.
Integration: A field trip to a nearby farm (if feasible) or bringing pictures of agricultural processes can link classroom learning to local agricultural practices.
Community Development and Material Use: Application: Understanding changes helps in appreciating how materials are used and managed. The burning of refuse (permanent change) in communities has environmental implications. The rusting of iron gates, bridges, or school structures (permanent change) highlights the need for maintenance and protection of materials. The process of making blocks from sand and cement (permanent change) is fundamental to construction in Nigeria.
Integration: Discuss the importance of proper waste disposal or why structures need to be painted to prevent rust, connecting science to community health and infrastructure.