"Diffusion: mysterious movement” experiment
Amazing experiment with lead nitrate and potassium iodide
Mysterious movement and magical materialization, all in one experiment!
Wear protective gloves and eye protection.
Warning! Don’t try to repeat this experiment without a professional supervision!
Reagents and equipment:
- lead nitrate (1 g);
- potassium iodide (1 g);
- water (200 mL);
- glass dish (1);
- plastic teaspoons (2).
Pour a cup of water into the glass dish. Introduce the lead nitrate and potassium iodide to the water on opposite sides of the dish from one another. In a minute, the salts will dissolve and a yellow precipitate will form a stripe in the center of the dish.
When lead nitrate and potassium iodide dissolve in water, they dissociate into ions. These ions don’t stay in one place – they gradually spread out through the whole dish in a process known as diffusion. When lead ions meet iodide ions, lead (II) iodide forms, appearing as an insoluble yellow precipitate.