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Thermal Energy & Temperature

Year 8 🌡️ Energy & Thermodynamics Relate thermal energy to particle movement; understand temperature scales.

⚛️ The Particle Model of Matter

All matter is made of tiny particles (atoms/molecules) that are constantly moving. The arrangement of particles determines the state of matter.

🧊 State	📐 Arrangement	🏃 Movement	📦 Compressible?
Solid ■	Regular, tightly packed	Vibrate only	❌ No
Liquid ≈	Random, close together	Slide past each other	❌ Almost no
Gas ·	Random, far apart	Move fast, randomly	✅ Yes, easily

🔬 The particles in even a solid object are always vibrating — they never completely stop (until absolute zero is reached)!

🌡️ Temperature and Internal Energy

Temperature measures the average kinetic energy of particles. Internal (thermal) energy is the total kinetic and potential energy of ALL particles in an object.

🫗 Why does a large pool of cold water have more internal energy than a hot cup of tea?
The pool has billions more particles. Even though each particle has less energy, the total (internal energy) is much larger!

💡 Key Distinction

↑ Temperature = ↑ average KE per particle
Internal energy depends on both temperature AND amount of substance

🧊 Absolute Zero and the Kelvin Scale

At absolute zero (0 K = −273°C), particles have the minimum possible kinetic energy. The Kelvin scale starts at this point.

🌡️ Temperature Conversion

$$T(K) = T(°C) + 273 \qquad T(°C) = T(K) - 273$$

🌡️ Reference point	°C	K
Absolute zero	−273°C	0 K
Freezing point of water	0°C	273 K
Body temperature	37°C	310 K
Boiling point of water	100°C	373 K
Surface of the Sun	≈5500°C	≈5773 K

🎯 Ready to test yourself? Click the Quiz tab above to answer questions on this topic!

⚗️ 🌡️ Temperature Converter (°C ↔ K)

Calculate heat energy transferred: Q = mcΔT

Mass (kg)

SHC c (J/kg°C)

Temp change ΔT (°C)

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