States of matter – particle model on heating and cooling
Integrated ScienceMatter & MaterialsAges 11–12Virtual lab
Use it with your class: students open it from a link or a QR code, with no account needed.
Next in Matter & Materials
In a solid, particles sit close together and only vibrate; in a liquid they slide past each other; in a gas they move freely. Click Heat or Cool, or drag the temperature slider, to watch the substance melt, boil, condense, and freeze; the temperature-vs-time graph flattens at the melting point and the boiling point. Choose water, ethanol, mercury, or oxygen to compare. The Evaporation screen shows energetic particles escaping from a liquid below its boiling point so that the liquid cools, the effect of temperature, surface area, wind and humidity, dynamic equilibrium under a lid, a clay pot that keeps water cool, and the sublimation of iodine and dry ice.
Lesson: The three states of matter and their properties; changes of state: melting, freezing, evaporation, boiling, condensation, sublimation; factors affecting the rate of evaporation
What it shows
The particle model explains the three states of matter by how particles are arranged and how they move. In a solid, particles are packed in a regular pattern and vibrate about fixed positions; in a liquid they stay close but slide past one another; in a gas they are far apart and move freely. At the melting point and the boiling point the temperature stays constant while the energy supplied changes the state. The Evaporation screen adds what happens below the boiling point: only the most energetic surface particles escape, so evaporation cools the liquid, and under a lid the rates of evaporation and condensation become equal.
How to use
On States, choose a substance and press Heat, Hold or Cool while watching the particles and the graph. On Evaporation, choose Dish, change Air temperature, Surface area, Wind and Humidity, and press Record to compare evaporation rates. Tick Close the lid and wait for dynamic equilibrium to read the vapour pressure. Clay pots compares a porous and a glazed pot; Sublimation heats iodine or dry ice.
Parameters you can change
- Substance Water (melts 0 °C, boils 100 °C), Ethanol (−114 °C, 78 °C), Mercury (−39 °C, 357 °C), Oxygen (−219 °C, −183 °C)
- Starting temperature -250–400 °C
- Heating / cooling rate 5–40 °C/s
- Number of particles 20–80
- Show temperature-vs-time graph
- Screen States of matter, Evaporation and sublimation
- Evaporation experiment Dish of liquid, Clay pots, Sublimation
- Liquid in the dish Water, Ethanol
- Air temperature 5–45 °C
- Surface area 10–200 cm²
- Wind speed 0–5 m/s
- Relative humidity 0–100 %
- Lid closed
- Subliming solid Iodine, Dry ice (solid CO₂)
- Hot plate temperature 20–110 °C
Questions to explore
- While water is boiling, does its temperature rise? What does the graph show during this time?
- How do the arrangement and motion of particles differ between a solid, a liquid and a gas?
- At −50 °C, what state are mercury and ethanol in?
Teaching ideas
All guides- States of Matter Lesson Plan with a SimulationA states of matter lesson plan with a free particle simulation: heat and cool four substances, compare attractions, read a heating curve, plus five questions.
- Physical and Chemical Changes Virtual Lab: Evidence and MassA physical and chemical changes virtual lab: run seven changes, weigh them in open and sealed containers, collect evidence and test conservation of mass.
