| Description |
We experimentally study the physics of camphoric acid loaded
agarose gel tablets (cboats) at the air-water interface. Camphoric
acid spreads over the air-water interface due to the interfacial tension
forces. When a cboat is placed at the air-water interface and let go,
it is spontaneously set in motion by the interfacial tension gradients.
We explain the cboat dynamics in terms of a dimensionless quantity
= a
u2 a2 , where a is the interfacial tension force acting along a
characteristic length a of cboat; u2 a2 is the drag force experienced
by the cboat. By de nition, = 1 when the interfacial tension force
and drag force are equal and the cboat moves with terminal velocity.
Through control of interfacial tension, we show three distinct modes,
viz. harmonic, steady, and periodic cboat motion arise for > 1,
1 and < 1 respectively.
1
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