Light & Energy

1. Why does the flame of a diya always point upward, even if you tilt the lamp?
2. Which uses more energy: lighting 20 diyas for 4 hours, or keeping one 100-watt bulb on for 1 hour?
3. Why do oil diyas sometimes flicker more than candles?

 Crackers & Chemistry

4. Firecrackers get their colours from metals. Match the pair:
   • Green → ?
   • Red → ?
   • Blue → ?
5. Which harmful gas, also found in cigarette smoke, is released during cracker explosions?
6. Why do animals and babies get more disturbed by cracker sounds than most adults?

 Environment & Health

7. On Diwali nights, why does a smoky haze stay trapped near the ground the next morning?
8. Which is safer for your lungs: a sparkler or an anar (fountain cracker) — and why?
9. Name one way solar-powered string lights are better than electric fairy lights.
10. What simple natural material can be used instead of chemical rangoli powders to make eco-friendly patterns?

 Answer Key

1. 1. Hot air rises (convection pulls flame upward).
   2. Diyas: ~240 Wh; bulb: 100 Wh → Diyas use more.
   3. Oil flow is uneven and wind disturbs open flame.
   4. Green = Barium, Red = Strontium, Blue = Copper.
   5. Carbon monoxide.
   6. Their ears detect higher frequencies and are more sensitive.
   7. Smoke mixes with cool night air and gets trapped near ground (temperature inversion).
   8. Sparkler — burns less fuel and makes less smoke.
   9. Solar lights save electricity, run on renewable energy, no wiring needed.
   10. Flower petals, rice flour, turmeric, coffee powder, leaves.    ————————————————