First chemistry (grades 7–8) · Grade 7
Heating water: when does it boil?
ChemAI · Worksheet
NameClassDate
Aim
Watch the thermometer while water turns into steam — a change of state.
Before you start: what do you predict will happen? Why?
What you do
| Step | What I observed | |
|---|---|---|
| 1 | Press “Heat” under the tube (speed ×5 helps). Watch the temperature rise. | |
| 2 | Keep heating until the water boils: bubbles of steam form inside the liquid. | |
| 3 | Read the thermometer: pure water boils at about 100 °C. Is boiling a physical or a chemical change? |
Questions
- Write a word or symbol equation for one reaction you observed.
- Explain your most important observation using particles, ions or energy.
- Was your prediction right? What would you change to get a more reliable result?