Thermodynamic Ice-Cube Salt String Fishing Lift

20 mins Ages 4-6 Indoor

A playful, screen-free adventure designed to spark curiosity, sensory exploration, and fine motor skills for kids aged 4 to 6.

Materials Needed

  • • Glass of cold water (1 unit)
  • • Fresh solid ice cubes (2 cubes)
  • • Cotton kite string or yarn (approx. 20 cm) (1 piece)
  • • Table salt shaker (1 shaker)

Pro Tips

  • → Float an ice cube in a cup of water and lay a damp cotton string directly across the top surface of the ice.
  • → Sprinkle a generous pinch of table salt across the string and ice cube, then wait 60 seconds without moving.
  • → The salt lowers the freezing point of water, melting a groove around the string. As the ice melts, it dilutes the salt, and the water refreezes over the string, allowing you to lift the ice cube straight out of the glass.

Safety First

Non-toxic kitchen experiment; wipe up spilled water from surfaces.

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Step-by-Step Instructions

1

Step 1

Fill a glass with cold tap water and float two ice cubes on the surface.

2

Step 2

Drape a 20 cm cotton string flat across the top surface of one floating ice cube.

3

Step 3

Sprinkle a pinch of table salt directly over the string and ice, waiting 60 seconds in silence.

4

Step 4

Gently pull both ends of the string straight up: the refrozen ice cube lifts out of the water like a caught fish.

What they are learning

Freezing-point depression thermodynamic physics Phase-change melting and refreezing Equilibrium crystallization capture