Know Science

06/04/2026

MATTER: CLASS 7 ICSE CHEMISTRY

Matter is anything that occupies space and has mass, forming the basis of the Class 7 Chemistry chapter on "Matter and Its Composition" in ICSE curricula like Selina Concise Chemistry.
Characteristics of Matter
Particles of matter are tiny and constantly in motion, with spaces between them and attractive forces holding them together. Matter cannot be created or destroyed and exists as homogeneous or heterogeneous mixtures.
States of Matter
Matter occurs in three main states: solids (fixed shape and volume, e.g., wood), liquids (fixed volume but takes container's shape, e.g., water), and gases (no fixed shape or volume, e.g., air).
Properties and Experiments
Matter has mass (proven by balloons with air tilting a scale) and occupies space (sand raises water level in a beaker). Gases are compressible and diffuse quickly due to large intermolecular spaces.
Interconversion
States change with temperature or pressure: melting (solid to liquid), evaporation (liquid to gas), condensation (gas to liquid), and freezing (liquid to solid). Ice melts to water at room temperature, then water can evaporate.

05/04/2026

Shout out to my newest followers! Excited to have you onboard! Pappu Singh, Ashim Ganguly, Biranchi Rout, Sabir Sk, Rekha Ghosh, Asfarul Islam, Archana Chaitali Sadhukhan, Bikash Bangal, Rahul Kumar, Debasish Das, Babla Halder

31/03/2026

31/03/2026

CROP PRODUCTION AND MANAGEMENT

CBSE Class 8 Science Chapter 1 is “Crop Production and Management”.
Here is a complete, concise set of notes you can use for revision and exam preparation.
1. What is a crop?
A crop is a large quantity of similar plants of one kind grown together for food, fibre, or other useful products.
Examples: wheat, rice, maize, cotton, pulses, vegetables.
2. Basic needs of crops
Nutrients (from soil, manure, fertilisers)
Water (irrigation)
Sunlight (for photosynthesis)
Proper climate (suitable temperature, rainfall)
3. Types of crops (by season)

4. Agricultural practices (steps)
1. Preparation of soil
Ploughing (tilling): Loosens soil, improves air circulation, helps roots pe*****te.
Levelling: Makes soil surface smooth so water spreads evenly.
W**ding (before sowing): Removal of unwanted plants (weeds) that compete for nutrients, water, and space.

2. Sowing of seeds
Seeds are sown into the prepared soil.
Good seeds should be healthy, disease‑free, and of a high‑yielding variety.
Methods:
Manual sowing (by hand)
Seed drill (machine that sows seeds uniformly at proper depth).

3. Adding manure and fertilisers

4. Irrigation
Supply of water to crops at regular intervals.
Common methods:
Drip irrigation (water drops exactly near roots – saves water)
Sprinkler system (water sprayed like rain)
Canals, wells, tube‑wells (flood the field).

5. Protection from weeds, pests, and diseases
W**ds: Removed by weeding (manual or using herbicides).
Pests/insects: Controlled by pesticides.
Diseases: Controlled by treating seeds with fungicides, proper crop rotation, etc.

6. Harvesting
Cutting and collecting mature crops from the field.
Can be:
Manual (sickle)
Mechanical (harvester combines).

7. Storage
Grains are dried before storage to prevent fungus and rot.
Stored in godowns, silos, or gunny bags, often with chemical preservatives or insecticides to protect quality.

5. Animal husbandry (brief)
Animal husbandry is the practice of rearing and breeding livestock (cows, buffaloes, poultry, goats, etc.) for milk, meat, eggs, and other products.
It includes proper feeding, cleaning, housing, and disease control of animals.

6. Key definitions (short form)
Crop: A large, similar group of plants grown for food or other use.
Kharif crop: Grown in rainy season.
Rabi crop: Grown in winter season.
Manure: Organic material added to soil to improve fertility.
Fertiliser: Chemical substance supplying plant nutrients.
Irrigation: Artificial supply of water to crops.
W**d: Unwanted plant growing with crops.
Harvesting: Gathering mature crops.
Storage: Keeping harvested grains safely for future use.

31/03/2026

BASICS OF CELL

30/03/2026

GOODS AND SERVICE TAX

ICSE Class 10 Biology Chapter 1 covers the cell as the structural and functional unit of life, marked for revision only in the syllabus. It introduces basic cell concepts essential for understanding later topics like cell division and genetics. This chapter emphasizes prokaryotic vs. eukaryotic cells, cell theory, and key organelles.
Cell Basics
Cells are the smallest units capable of independent function and form all living organisms. Unicellular organisms like Amoeba consist of one cell, while multicellular ones like humans have many specialized cells. Cell theory states that all living things are composed of cells, cells are the basic unit of life, and new cells arise from pre-existing ones.
Cell Structure
The plasma membrane encloses the cell, regulating entry and exit of substances. Plant cells have an additional rigid cell wall for support. Cytoplasm, the jelly-like medium, houses organelles, while the nucleus acts as the control center containing chromatin (DNA and histones).
Key Organelles
Nucleus directs cell activities via chromatin fibers that condense into chromosomes during division. Mitochondria produce energy (powerhouse), endoplasmic reticulum transports materials, and ribosomes synthesize proteins. Lysosomes digest waste, acting as suicidal bags if ruptured.
Cell Variations
Cells vary in number (unicellular/multicellular), shape (spherical, elongated), and size. Protoplasm includes nucleus and cytoplasm; inclusions like vacuoles store substances. Microscopic onion peel exams reveal plant cell outlines stained with safranin.