🔥 Thermodynamics Explorer

Ideal Gas Law · Heat Transfer · Phase Changes · Laws of Thermodynamics

🧪 PV = nRT — Solve for any variable

P = pressure (Pa) · V = volume (m³) · n = moles · R = 8.314 J/(mol·K) · T = temperature (K)

BOYLE'S LAW
P₁V₁ = P₂V₂
T constant
CHARLES'S LAW
V₁/T₁ = V₂/T₂
P constant
GAY-LUSSAC
P₁/T₁ = P₂/T₂
V constant

🌡️ Temperature Converter

Celsius (°C)
Fahrenheit (°F)
Kelvin (K)

⚙️ Gas State Explorer

Adjust variables — pressure is calculated

Volume (L)10.0 L
Moles (mol)1.0 mol
Temperature (K)300 K
2494
Pa (Pressure)
P = nRT/V
R = 8.314 J/(mol·K)
1 atm = 101,325 Pa

Particles collide elastically — higher temperature = faster particles

⚙️ Controls

Temperature300 K
Particles30
Kinetic Theory:
Average KE ∝ Temperature
KE = ½mv²
v_rms = √(3RT/M)
—
Avg speed (relative)

🌡️ Specific Heat — Q = mcΔT

Heat added to raise m kg by ΔT degrees

Material
Mass (kg)1.0 kg
ΔT (°C)50 °C
209,300
Joules (Q)

🔥 Fourier's Law — Heat Conduction

Q/t = k·A·ΔT/d (W)

Material (k)
Area (m²)0.10 m²
ΔT (K)50 K
Thickness d (m)0.01 m
—
Watts (heat flow rate)
🔗 Conduction

Heat flows through direct contact between particles. Fast in metals (free electrons), slow in insulators.

🌊 Convection

Warm fluid rises, cool fluid sinks — creating circulation currents. How ovens, oceans, and weather work.

☀️ Radiation

Electromagnetic waves carry energy without needing matter. How the Sun's heat reaches Earth through space.

💧 Phase Diagram (Water)

🧊 Solid (Ice)
💧 Liquid (Water)
♨️ Gas (Steam)
● Triple Point (0.006 atm, 0.01°C)
● Critical Point (218 atm, 374°C)
MELTING / FUSION

Solid → Liquid. Occurs at melting point (0°C for water). Requires energy = latent heat of fusion.

VAPORISATION

Liquid → Gas. Boiling: at 100°C (1 atm). Evaporation: at any temperature at the surface.

SUBLIMATION

Solid → Gas directly, skipping liquid. Dry ice (CO₂) sublimates at −78.5°C at 1 atm.

CONDENSATION

Gas → Liquid. Releases the same latent heat that was absorbed during vaporisation.

Zeroth Law
Thermal Equilibrium
If object A is in thermal equilibrium with object C, and object B is also in thermal equilibrium with C, then A and B are in thermal equilibrium with each other. This is the basis of thermometry — it's what makes temperature a meaningful concept.
A↔C and B↔C ⟹ A↔B
First Law
Conservation of Energy
Energy cannot be created or destroyed — only converted between forms. The change in internal energy of a system equals heat added minus work done by the system. You can't get more energy out than you put in.
ΔU = Q − W
Second Law
Entropy Always Increases
Heat spontaneously flows from hot to cold, never the reverse. The entropy (disorder) of an isolated system always increases over time. This is why heat engines are never 100% efficient — some energy is always lost to the environment. It's why time has a direction.
ΔS_universe ≥ 0
Third Law
Absolute Zero
The entropy of a perfect crystal at absolute zero (0 K = −273.15°C) is exactly zero. As temperature approaches 0 K, the entropy approaches zero. It is impossible to reach absolute zero in a finite number of steps.
lim(T→0) S = 0

⚙️ Carnot Engine — Maximum Efficiency

The most efficient possible heat engine operating between two temperatures. Real engines are always less efficient due to friction and other irreversibilities.

T_hot (K)
T_cold (K)
50.0%
Max efficiency (η = 1 − T_cold/T_hot)
What is thermodynamics?

The study of heat, work, temperature, and energy. It governs everything from steam engines to refrigerators to the Sun — any system that converts energy between forms.

The Ideal Gas Law

PV = nRT relates pressure, volume, moles, and temperature for an "ideal" gas (point particles, no intermolecular forces). Real gases deviate at high pressures and low temperatures. R = 8.314 J/(mol·K).

Key concepts
  • Temperature — average kinetic energy of particles
  • Heat (Q) — energy transferred due to temperature difference
  • Work (W) — energy transferred by force × distance
  • Internal energy (U) — total kinetic + potential energy of particles
  • Entropy (S) — measure of disorder; always increases in isolated systems
  • Enthalpy (H) — heat content at constant pressure: H = U + PV
  • Latent heat — energy for phase change without temperature change
🎯 Try this challenge

Using PV = nRT, if you double the temperature (in Kelvin) of a gas at constant volume, what happens to the pressure? Try it with the Ideal Gas Law tool. Then explain it using the particle model.

Continue Learning
Physics Formulas