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2A10.20 - Floating Dense Objects on Water

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​2A10.20 - Floating Dense Objects on Water

Title2A10.20 - Floating Dense Objects on Water

Show how surface tension of water is strong enough to allow dense objects to float.

Assembly Instructions
Overview:  Use cool filtered water.  May use 'raft' of tissue paper w/ object on top, the raft will sink after a few moments leaving the objects floating on the surface.  Use white background for the camera.
Instructions:  A razor blade, needle, or wire gauze basket can be made to float on water quite easily.  In order to make the demonstration visible, place a shallow dish of water on the overhead projector.  The objects should be clean and slightly oiled for best results; there should be no surface wetting agents, such as soap, present.  One of each item is kept ready for use in the kit.  The basket may be made to sink by merely adding one drop of water to the interior area.  It is conenient to use a small wire hanger to place the objects on the surface.
Setup Time15
Operation Time
Preview Time2
Operation Instructions

1. Switch the camera so the students can see the Petri dish full of water.
2. Pick up an object with the tweezers or bent fork and place it on the surface of the water gently.
3. Observe the object floating on the surface of the water.​

Demo on DimeNo
PIRA 200Yes
Export Instructions (if different)
Category2 Fluid Mechanics
Subcategory2A - Surface Tension
Keywordssurface tension, razor blade, needle, wire gauze, density, water, float
Construction Information
overhead projector
razor blade
wire gauze basket
shallow dish for water
water - from the tap