📖 Theory & Concepts ▼

1. Phase Transitions

Property Melting Point Boiling Point
Definition Solid → Liquid Liquid → Gas
Water (at 1 atm) 0°C 100°C
Temp. during change Remains constant
Energy absorbed Latent heat of fusion Latent heat of vaporization

2. Key Concepts

  • Latent Heat Heat absorbed without temperature change. Used to overcome intermolecular forces during phase change.
  • Pressure Effect At higher altitudes (lower pressure), water boils below 100°C. At higher pressure, it boils above 100°C.
  • Purity Test Pure substances have sharp melting/boiling points. Impurities cause these to change.
Did you know? On Mount Everest, water boils at just 71°C due to the low atmospheric pressure — not hot enough to make good tea!
⚠️ Safety First ▼
  • Boiling water & steam — steam causes worse burns than boiling water. Keep your face away from the beaker mouth and never lean over it.
  • Bunsen burner — tie back long hair, keep flammables away, and return to the luminous (safety) flame when not heating.
  • Anti-bumping — add a few boiling chips/anti-bumping granules so superheated water does not suddenly erupt.
  • Thermometer is fragile — clamp it so the bulb is immersed but not touching the hot base of the beaker; handle a broken thermometer as hazardous waste.
  • Hot glassware looks the same as cold — use a holder and let the beaker cool before moving it.
  • Wear safety goggles throughout.

🎯 Lab Mode

🔮 Predict before you heat

Lock a prediction to enable the action button. Switching mode re-arms it.

Experimental Theory

Melting point is the temperature where solid turns to liquid. For pure ice, this is 0°C. Temperature remains constant during the phase change.

Crucial Note

Position the thermometer bulb deep in the substance without touching the beaker walls for an accurate reading.

Procedure
Pressure: 1.0 atm
Temperature
25.0 °C
Drag the thermometer into the beaker
Lab Journal
Waiting for readings...

Recorded Results

Melting Pt (Ice) ---
Boiling Pt (Water) ---