Probability Class 11 One Shot NCERT Maths Full Chapter 16 CBSE 2025-26 Exam by Kuldeep Sir

Science: Core Concepts in Physics, Chemistry, and Biology

Science is the systematic study of the natural world through observation, experimentation, and reasoning. The CBSE Science curriculum integrates Physics, Chemistry, and Biology. This chapter covers core scientific concepts essential for understanding the world around us and for success in CBSE examinations.

The scientific method: (1) Make observations. (2) Ask a question. (3) Formulate a hypothesis (testable explanation). (4) Conduct experiments (control group, one independent variable). (5) Analyse data and draw conclusions. (6) Communicate results. Theories are well-substantiated explanations supported by evidence. Laws describe what happens; theories explain why.

Matter: elements (one type of atom), compounds (two+ elements chemically combined), mixtures (physically combined, separable). Physical changes (change in state, no new substance) vs chemical changes (new substances formed). Atoms consist of protons, neutrons, and electrons. The periodic table organises elements. Chemical reactions involve the rearrangement of atoms — balanced equations show mass conservation.

Energy exists in many forms: kinetic (motion), potential (stored), thermal, chemical, electrical, nuclear, light, and sound. The law of conservation of energy: energy cannot be created or destroyed, only converted from one form to another. Living organisms are made of cells. The cell is the basic unit of life. Plants perform photosynthesis to produce food. Animals obtain food by consuming other organisms. Ecosystems involve interactions between living organisms and their environment. Biodiversity is essential for ecosystem stability and human well-being.

• Scientific method: Observe -> Question -> Hypothesise -> Experiment -> Analyse -> Conclude.
• Matter: elements (pure, one type of atom), compounds (two+ elements combined), mixtures (physically combined).
• Energy: kinetic (motion), potential (stored), thermal, chemical. Law: energy cannot be created/destroyed, only converted.
• Cell: basic unit of life. Cell theory (Schleiden, Schwann, Virchow). Prokaryotes vs eukaryotes.
• Chemical reactions: atoms rearrange, mass conserved. Balanced equations show stoichiometric relationships.