🌟 Class 7 Science Curiosity – Chapter 11 Notes
🔦 Light: Shadows and Reflections | Amresh Academy
📘 Introduction
💡 1. Sources of Light
🔆 Luminous Objects:
👉 Produce their own light
- ☀️ Sun
- ⭐ Stars
- 🐞 Fireflies
- 💡 Bulbs
🌙 Non-Luminous Objects:
- 🌙 Moon
🌿 Types of Sources:
- 🌞 Natural → Sun, stars, lightning
- 🕯️ Artificial → Candle, bulb, LED
⚡ LED Lamps:
- Energy efficient 💡
- Long-lasting
- Eco-friendly 🌍
📏 2. Light Travels in a Straight Line
🧪 Experiments:
- 📦 Matchbox → Light passes through aligned holes
- 🔧 Pipe → Straight pipe shows flame, bent pipe doesn’t
- 🔴 Laser → Moves straight even in water
🧱 3. Light and Materials
🔍 Types:
✔️ Transparent:
👉 Light passes completely
- Glass
🌫️ Translucent:
👉 Light passes partially
- Tracing paper
❌ Opaque:
👉 Light is blocked
- Cardboard
🌑 4. Shadow Formation
📌 Shadow:
👉 Dark region formed when light is blocked
🔑 Requirements:
- Light source 💡
- Opaque object 🧱
- Screen (wall)
🧠 Observations:
- Opaque → dark shadow
- Translucent → light shadow
- Size depends on position
- Color doesn’t affect shadow
🪞 5. Reflection of Light
📌 Definition:
👉 Light bounces back from a surface
🔍 Example:
- Mirror 🪞
- Shiny surfaces
🪞 6. Images in a Plane Mirror
📊 Properties:
- Same size 📏
- Upright (erect) ✔️
- Virtual image
- Laterally inverted 🔄 (left-right reversed)
🚑 Example:
👉 “AMBULANCE” appears reversed in mirror
📷 7. Pinhole Camera
📌 Definition:
👉 Device that forms image through a small hole
🧠 Image Properties:
- Inverted (upside down) 🔄
- Shows colors 🎨
🛠️ Construction:
- Cardboard box
- Small hole
- Screen
🔍 8. Useful Devices
🔭 Periscope:
- Uses mirrors
- Helps see around corners
🎨 Kaleidoscope:
- Uses mirrors
- Creates beautiful patterns
📌 Final Summary
👉 Light helps us understand:
- Shadows 🌑
- Reflection 🪞
- Images 📷
🔑 Key Concepts:
- Light travels straight 📏
- Materials affect light 🧱
- Mirrors form images 🪞
- Devices use reflection 🔭
✨ Perfect for revision + exams + concept clarity 🚀
