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Floating vs. Sinking Smart Water Lab

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Predict and test objects in a water tub with a waterproof ultrasonic sensor that detects water level changes. The speaker announces 'It SANK!' or 'It FLOATS!' instantly.

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Props & Materials Required

  • •Large clear plastic tub filled with water
  • •Objects: plastic block, metal spoon, wooden stick, dry leaf, stone, sponge, cork, plastic bottle cap
  • •Prediction chart poster

Step-by-Step Instructions

1

Make Predictions

Hold up an object. Have children mark their prediction on a chart under 'Float' or 'Sink'.

2

Drop and Detect

Gently drop the object into the water. The waterproof sensor detects water level rise (sinking object displaces more water). Speaker announces: 'The STONE sank! Water level rose!'

3

LED Feedback

Blue LED for float, Red LED for sink. The scoreboard display tracks: 'Floaters: 4, Sinkers: 3'.

4

Sponge Mystery Experiment

Test a dry sponge (it floats — blue LED!). Wait as it absorbs water. Sensor detects the slow sinking. Speaker: 'The sponge absorbed water and became heavy — now it sinks!'

Why It Works & Notes

Buoyancy is a dramatic physical phenomenon. Sensor-based instant detection replaces ambiguous visual judgment — children get definitive audio confirmation of their experimental results.