✨ Golden rain: virtual chemistry experiment
Make lead(II) iodide, dissolve it hot, then watch glittering golden crystals form on cooling.
▶ Launch this experiment freeRuns in your browser on any phone, tablet or laptop. No sign-up, no install, no chemicals needed.
What you'll do
- Add 1 mL potassium iodide (dropper) twice: a bright yellow precipitate forms
- Add 25 mL + 10 mL distilled water, then light the burner and heat until the yellow solid dissolves
- Turn off the burner and move the tube into the ice bath
- Watch golden crystals "rain" down as it cools
The chemistry behind it
Pb²⁺ + 2I⁻ → PbI₂↓. PbI₂ is much more soluble in hot water. As the solution cools it becomes supersaturated and PbI₂ crystallises as shimmering golden plates.
Why do this experiment virtually?
Many school labs can't run this experiment safely or don't have the chemicals. In Faradium you set it up in seconds, repeat it as often as you like, change the amounts and see the real result: colours, gases, precipitates and temperature changes. The lab notebook records every observation with the balanced equation for your write-up.
Frequently asked questions
How do you do the golden rain experiment?
1. Add 1 mL potassium iodide (dropper) twice: a bright yellow precipitate forms 2. Add 25 mL + 10 mL distilled water, then light the burner and heat until the yellow solid dissolves 3. Turn off the burner and move the tube into the ice bath 4. Watch golden crystals "rain" down as it cools You can run every step free in the Faradium virtual chemistry lab.
What is the chemistry behind golden rain?
Pb²⁺ + 2I⁻ → PbI₂↓. PbI₂ is much more soluble in hot water. As the solution cools it becomes supersaturated and PbI₂ crystallises as shimmering golden plates.
Can I do the golden rain experiment online for free?
Yes. Faradium sets up the bench for you and ticks off each step as you complete it. It runs in any browser on a phone, tablet or laptop with no sign-up and no chemicals.
Chemistry in this experiment
Elements involved: Iodine (I), Lead (Pb).
Molar masses you may need: H2O.
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