Explore & Learn

Page number 80 and 81.

Metals are natural compounds of earth’s crust, in which they are generally found in the form of metal ores, associated both with each other and with many other elements. They are also naturally present in the rocks washed by surface water and groundwater and in atmospheric dust.

Metals are substances that form naturally below the surface of the Earth. Most metals are lustrous or shiny. Metals are inorganic, which means they are made of substances that were never alive.

Metal is very strong and durable and therefore is used to make many things. These are used for making automobiles, satellites, cooking utensils, etc.

Most metals are hard but some are not. Sodium and potassium are such metals that can be cut by knife whereas mercury is a liquid metal at room temperature. Iron is solid in natural.

There are 93 metallic elements out of the 118 elements on the periodic table. These elements are classified into five groups: alkaline earth metals, alkali metals, transition metals, actinides, and lanthanides. While there are roughly 70 naturally occurring metals, the total number of metallic elements, including those produced artificially, is 93. 

Physical Properties of Metals

• All the metals are good conductors of heat and electricity. Cooking utensils and irons are made up of metals as they are good conductors of heat.

  
  

• Ductility is the ability of the material to be stretched into a wire. This ability allows metals to be drawn into wires and coupled with their durability, find applications as cable wires and for soldering purposes. Because Metal can be drawn into wires we can say that metals are ductile.

  
  

• Malleability is the property of substances which allows them to be beaten into flat sheets. Aluminium sheets are used in the manufacturing of Aircrafts because of their lightweight and strength. Other metal sheets are used in automobile industries, for making utensils, etc. Therefore, metals are malleable.

  
  

• Metals are sonorous because they produces a deep or ringing sound when struck with another hard object.

  
  

• Usually, all the metals have a shiny appearance but these metals can also be polished to have a shiny appearance.

Ch : 5 States of Matter

Pages No. 68,69

Introduction

• The three states of matter are solid, liquid, and gas. Examples of each state include: 

  • Solids: Ice, wood, stone, iron, bricks, paper, concrete, glass, dry ice, salt, and most metals and minerals 

  • Liquids: Water, milk, juice, oil, alcohol, and mercury 

  • Gases: Air, helium, hydrogen, oxygen, nitrogen, carbon dioxide, and natural gas 

• The state of matter depends on how the particles are arranged and how much energy they have.

Solids 

• Have a definite shape and volume

• Particles are closely packed together and vibrate in place

Liquids 

• Have a definite volume but can change shape

• Particles are loosely bonded and move around but stay close together

• Take the shape of their container

Gases 

• Have neither a definite shape nor volume

• Particles move freely and spread apart from one another

• Fill their container, taking both the shape and the volume of the container

page number 64 and 65.

Introduction

Invertebrates are animals that neither posses nor develop a vertebral column, derived from the notochord. These include all animals apart from the subhylum Vertebrata.

Invertebrates are animals with no backbone. 97 of the animals are invertebrates among the estimated 2.16 million animal specie. Invertebrates exist about anywhere. These have been found in the driest deserts, high reaches of atmosphere and canopies of wettest rainforests. They also exist in the frozen antartica or under the deepest oceans.

Wheather batting aaway irritating flies, unearthing a worm or admiring the complexity of a spiders web and much more, all these animals are invertebrates.

Invertebrates are so many that its almost impossible to count them all. There are so many invertebrate animal species of diffrent shapes an sizes that help is in many ways and are vital to our survival.

Characteristics of invertebrates

By now as you know what invertebrates are, lets get to know about their characteristics.

• All invertebrates do not have a spinal cord or vertebal column, instead, most of them posses an exoskeleton that encompasses the entire body.

• Normally, these are tiny and dont grow very large.

• Do not possess lungs since they respire through their skin.

• Since they cannot produce their own food, Invertebrates are heterotrophic.

• Reproduction occurs through fission.

Page number 62 and 63.

One of the ways life is classified is through the presence or absence of the vertebrates. Vertebrates and invertebrates evolved from a common ancestor that was speculated to have lived around 600 million years ago.

Evidence of true vertebrates began to appear 525 million years ago and ever since then, vertebrates have branches off into a long lineage that includes armoured fish and giant sauropods to wolly mammoths and modern man.

1. Mammals

Mammals are warm-blooded animals with hair or fur. Most give birth to live babies and feed them milk. They breathe with lungs and can live on land or in water. Examples are humans, dogs, and whales. They usually take good care of their babies.

2. Birds

Birds are warm-blooded and have feathers and wings. Most can fly, and all lay eggs. They have beaks and breathe with lungs. Examples include eagles, penguins, and parrots. Birds often build nests to keep their eggs safe.

3. Reptiles

Reptiles are cold-blooded with dry, scaly skin. They usually lay eggs and breathe with lungs. Many live in hot places. Snakes, lizards, and turtles are reptiles. Some reptiles can go a long time without eating.

4. Amphibians

Amphibians are cold-blooded and live in water when young and on land when older. They have smooth, wet skin and lay eggs in water. Frogs and salamanders are amphibians. They need water to keep their skin moist.

5. Fish

Fish are cold-blooded animals that live in water. They have gills to breathe and fins to swim. Most have scales and lay eggs. Examples are goldfish, salmon, and tuna. They come in many colors, shapes, and sizes.

6. Cartilaginous Fish

These fish have skeletons made of cartilage, not bone. They live in water and have fins and gills. Sharks and rays are examples of cartilaginous fish. They are often fast swimmers and great hunters.

7. Jawless Fish

Jawless fish have no jaws or bones. They have soft bodies and suck their food. Lampreys and hagfish are jawless fish and are very old types of animals. They have a slimy body to protect themselves.

Page number 58 and 59.

Classifying plants is key to understanding the incredible variety of plant life on Earth. It helps scientists identify and group plants, uncovering their evolutionary relationships and traits. This knowledge is vital for conservation efforts, as it helps track endangered species and protect ecosystems. In agriculture and medicine, plant classification identifies useful species for food, medicine, and industry. Plus, it enhances our understanding of how plants contribute to their environments, from supporting pollinators to sustaining habitats. In short, plant classification is crucial for both science and practical applications that benefit nature and humanity.

1. By Type:

• Flowering Plants (Angiosperms): These plants produce flowers and seeds. Examples include roses, daisies, and apple trees.

• Non-Flowering Plants (Gymnosperms): These plants don’t produce flowers but produce seeds in cones. Examples include pine trees and fir trees.

2. By Size and Form:

• Trees: Large, woody plants with a single trunk (e.g., oak, pine).

• Shrubs: Smaller, woody plants with multiple stems (e.g., rose bush).

• Herbs: Small, non-woody plants (e.g., mint, basil).

3. By Leaf Type:

• Deciduous Plants: Lose their leaves in the fall (e.g., maple tree).

• Evergreen Plants: Keep their leaves year-round (e.g., pine tree).

4. By Habitat:

• Aquatic Plants: Live in water (e.g., water lilies).

• Terrestrial Plants: Live on land (e.g., grass, trees).

• Epiphytes: Grow on other plants but are not parasitic (e.g., orchids).

The individual most widely recognized for developing the classification system of plants is Carl Linnaeus (1707–1778), a Swedish botanist, zoologist, and physician. Linnaeus is renowned for establishing the system of binomial nomenclature, which assigns each species a two-part Latin name consisting of the genus and species. His seminal work, Systema Naturae, first published in 1735, laid the groundwork for modern taxonomy.

Linnaeus classified plants primarily based on their reproductive structures, particularly focusing on the number and arrangement of stamens and pistils in flowers. While his classification system formed the foundation for subsequent taxonomic work, modern taxonomy has since evolved, incorporating genetic data in addition to morphological characteristics.