The stickiness of water experiment
Yep, it’ true. Water has a certain ‘stickiness’ to it. Read on…
- Make five holes in the side of the can (using the nail). Make sure the holes are made near the base of the can.
- Fill the can with water.
- Pinch the streams of water together with your thumb and finger.
All about surface tension
The streams of water are held together by the water’s “stickiness,” or surface tension. Surface tension is the tendency of the surface of a liquid to behave as though covered with skin. Surface tension is what allows objects with a higher density than water such as razor blades and insects (e.g., water striders), to float on a water surface without becoming even partly submerged.
This is due to the cohesive forces between the molecules at and near the surface. Due to the cohesive forces, a molecule located away from the surface is pulled equally in every direction by neighboring liquid molecules, resulting in a net force of zero. The molecules at the surface do not have the same molecules on all sides of them and therefore are pulled inward. This creates some internal pressure and forces liquid surfaces to contract to the minimum area.
There is also a tension parallel to the surface at the liquid-air interface, which will resist an external force due to the cohesive nature of water molecules. The forces of attraction acting between molecules of the same type are called cohesive forces, while those acting between molecules of different types are called adhesive forces.
Surface tension experiment supplies
Supplies: Coffee can
In-Article Image CreditsWater droplet lying on a damask textile due to surface tension and low absorption of textile via Wikimedia Commons by Petar Milosevic with usage type - Creative Commons License. January 1, 2017
Featured Image CreditWater droplet lying on a damask textile due to surface tension and low absorption of textile via Wikimedia Commons by Petar Milosevic with usage type - Creative Commons License. January 1, 2017