1. The Goal of Science

In Grade 8, the focus shifts to the "Investigative World of Science".

• The goal is not just to learn facts, but to learn how to find new facts.
• This involves asking focused questions, designing simple experiments, and using observations to improve understanding.

2. Key Scientific Concepts

• Microbes: Invisible organisms that can be helpers (digestion, medicine) or harmful (infections).
• Electricity: Has a heating effect (to keep warm) and a magnetic effect (to run motors).
• Forces & Pressure: Explain why objects fall or stop. Pressure differences drive winds and cyclones.
• Classification: Materials are classified into Elements (pure), Compounds, and Mixtures.
• Light: We study how light reflects (mirrors) and bends (lenses/glasses).

3. Systematic Investigation (The Puri Example)

To investigate why a puri puffs up:

• Variables to Change (Independent): Dough thickness, flour type, oil temperature.
• Controlled Variables: Keep everything else the same (e.g., if testing thickness, keep oil temperature constant).
• Observation: Measure if it puffs or how long it takes.