Surface Tension/Cohesion and Adhesion
When water is dropped onto a penny it forms a do-shaped bubble above the penny. This is called Surface Tension. The molecules of the water stick together as they get drooped onto the penny.
When the soap was added to the penny the cohesion of the molecules decreased and adhesion occurred with the water molecules and soap molecules bonding together.
The molecules are bonding with each other to form the dome like shape on top of the penny.
Wax paper and water are another example of cohesion because the droplets do not form with the substance of the wax paper but with itself. when the water bonded with the wax paper it went from cohesion to adhesion.
Cohesion and surface tension are taking place because the water molecules are bonding with each other.
Polarity of Water
In this experiment the salt was polar and the cooking oil was non-polar. The salt dissolved into the water and the cooking oil did not. The cooking oil bubbled up to the top as it was stirred and the salt goes to the bottom then dissolves into the water.
The salt dissolves into the water as it gets stirred.
The cooking oil goes to the top of the water and sits in bubbles as it gets mixed around.
Real World Examples
- An example of surface tension would be insects that walk on water. The molecules of the spider do not bond with the ones in the water.
The spider's molecules are not interacting with the water's molecules.
- An example of polarity in the real world would be sugar. Sugar dissolves into the water as it gets mixed around.
The sugar is dissolving into the water therefore it is polar.