Topics
Heredity and Evolution
- Heredity
- Protein Synthesis
- Transcription
- Translation
- Translocation
- Mutations
- Evolution
- Evidence of Evolution > Morphological Evidences
- Evidence of Evolution > Anatomical Evidences
- Darwin’s Theory of Natural Selection (Darwinism)
- Lamarck’s Theory of Evolution (Lamarckism)
- Speciation
- Human Ancestors
- Homo Sapiens Sapiens (Modern Man)
Life Processes in Living Organisms Part -1
- Life Processes in Living Organisms
- Living Organisms and Energy Production
- Phases of Respiration: Glycolysis
- Phases of Respiration: Tricarboxylic Acid Cycle (Citric Acid Cycle or Kreb’s Cycle)
- Phases of Respiration: Electron Transport Chain (Electron Transfer System)
- Production of ATP
- Cellular Respiration
- Energy From Different Food Components
- Cell Division: an Essential Life Process
- Mitosis > Karyokinesis (Division of Nucleus)
- Mitosis > Cytokinesis (Division of Cytoplasm)
- Significance of Mitosis
- Meiosis: Reduction Division
- Stages of Meiosis: Meiosis I
- Stages of Meiosis: Meiosis II
- Significance of Meiosis
- Mitosis Vs Meiosis
Life Processes in Living Organisms Part - 2
Environmental Management
Towards Green Energy
- Energy and Use of Energy
- Generation of Electrical Energy
- Power Plants Based on Nuclear Energy
- Power Plant Based on Thermal Energy
- Power Plants Based on Natural Gas
- Electric Energy Generation and Environment
- Electricity Generation using Hydroelectric Energy
- Electricity Generation using Wind Energy
- Electricity Generation using Solar Energy
- Solar Photovoltaic Cell
- Solar Thermal Power Plant
Animal Classification
- Classification of Living Organisms
- History of Animal Classification
- Traditional Method of Animal Classification
- Conventional System of Animal Classification
- Criteria for New System of Classification > Grades of Organization
- Criteria for New System of Classification > Body Symmetry
- Criteria for New System of Classification > Germ Layers
- Criteria for New System of Classification > Body cavity (Coelom)
- Criteria for New System of Classification > Body Segmentation
- Phylum: Porifera
- Phylum: Cnidaria/Coelenterata
- Phylum: Platyhelminthes
- Phylum: Aschelminthes
- Phylum: Annelida
- Phylum: Arthropoda
- Phylum: Mollusca
- Phylum: Echinodermata
- Phylum: Hemichordata
- Phylum: Chordata
- Subphylum: Urochordata
- Subphylum: Cephalochordata
- Subphylum: Vertebrata/Craniata
- Subphylum: Vertebrata/Craniata > Class: Cyclostomata
- Subphylum: Vertebrata/Craniata > Class: Pisces
- Subphylum: Vertebrata/Craniata > Class: Amphibia
- Subphylum: Vertebrata/Craniata > Class: Reptilia
- Subphylum: Vertebrata/Craniata > Class: Aves
- Subphylum: Vertebrata/Craniata > Class: Mammalia
Introduction to Microbiology
Cell Biology and Biotechnology
- Cell Biology (Cytology)
- Stem Cells
- Stem Cell Research
- Organ Transplantation
- Organ and Body Donation
- Biotechnology
- Crop Biotechnology > Hybrid Seeds
- Crop Biotechnology > Genetically Modified Organisms (GMOs)
- Crop Biotechnology > Biofertilizers
- Animal Husbandry (Livestock)
- Human Health
- Vaccines and Vaccination
- Edible Vaccines
- Treatment
- Interferons
- Gene Therapy
- Cloning
- Industrial Products/White Biotechnology
- Environment and Biotechnology
- Food Biotechnology
- DNA Fingerprinting
- Green Revolution
- White Revolution
- Blue Revolution
- Fertilizers
- Insecticides
- Types of Farming in India > Organic Farming
- Animal Husbandry (Livestock) > Apiculture (Bee Farming)
- Cultivation of Medicinal Plants
- Processing and Preservation of Fruits
Social Health
Disaster Management
Life's Internal Secrets
- Autotrophic Plants
- Heterotrophic Plants
- Human Digestive System
- Nutrition in Plants
- Transport
The Regulators of Life
The Life Cycle
Mapping Our Genes
Understanding Metals and Non-Metals
Striving for Better Environment 2
- Use of Efficient and Eco-friendly Technology
- Sustainable Use of Resources
- Enforcement of Acts, Laws and Policies
Amazing World of Carbon Compounds
Maharashtra State Board: Class 8
Introduction
Metals are found in the earth’s crust, usually as metal ores mixed with other elements. They are also present in rocks, water, and atmospheric dust. Metals are strong and durable, used to make automobiles, satellites, cooking utensils, and more. Most metals are hard, but some, like sodium and potassium, are soft enough to be cut with a knife. Mercury is a unique metal that is liquid at room temperature.
Examples of metals are gold, silver, iron, copper, aluminium, magnesium, calcium, sodium, and platinum.
General Properties of Metals
| Lustre | Metals have a shiny appearance and reflect light. |
| Hardness | Most metals are hard, though some (like sodium and potassium) are soft. |
| Malleability | Metals can be hammered into thin sheets without breaking. |
| Ductility | Metals can be drawn into wires. |
| High Melting and Boiling Points | Metals generally have high melting and boiling points (except for mercury, which is liquid at room temperature). |
| Good Conductors | Metals conduct heat and electricity efficiently. |
| High Density | Metals usually have a high density, making them heavy. |
| Sonorous | Metals produce a ringing sound when struck. |
| Form Cations | Metals lose valence electrons to form positively charged ions (cations). |
Maharashtra State Board: Class 8
Experiment
1. Aim: To observe the physical properties, such as lustre and malleability, of different objects made from iron, copper, aluminium, and carbon.
2. Requirements: iron nail or sheet, copper wire, aluminium wire, piece of coal, sandpaper, and hammer.
3. Procedure
- Rub each object (iron, copper, aluminium, and coal) on sandpaper to reveal a fresh surface and observe if it has lustre (shiny appearance) or is pale.
- Carefully hammer each object with force to see if it is malleable (can be hammered into thin sheets) or brittle (breaks easily).
| Object | Is the surface shining? Yes/No | Does the shape flatten/break into small pieces on hammering? |
|---|---|---|
| Iron nail | Yes | Flattens |
| Copper wire | Yes | Flattens |
| Aluminium wire | Yes | Flattens |
| Coal piece | No | Breaks into small pieces |
| Category | Elements |
|---|---|
| Elements having a shiny surface | Iron, Copper, and Aluminium |
| Elements that flatten on hammering | Iron, Copper, and Aluminium |
| Elements with a dull surface | Carbon (Coal piece) |
| Elements that break on hammering | Carbon (Coal piece) |
4. Conclusion: The experiment shows that elements have different physical properties
- Metals like iron, copper, and aluminium have lustre and are malleable. Nonmetals like carbon (coal) are dull and brittle.
- This experiment demonstrates the basic classification of elements into metals and non-metals based on their physical characteristics. Further details will be explored in the study of metals and nonmetals.
