Measuring surface tension

Causes[ edit ] Diagram of the forces on molecules of a liquid Due to the cohesive forces a molecule 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 minimal area. The forces of attraction acting between the molecules of same type are called cohesive forces while those acting between the molecules of different types are called adhesive forces.

Measuring surface tension

Glass, cup or small bowl Tap water Dish towel or paper towel Flat, level surface that can get wet, such as a kitchen counter Paper and pencil or pen optional Preparation Place your penny on a flat, level surface that can get a little wet, such as a kitchen Measuring surface tension.

Fill a glass, cup or small bowl with tap water. Procedure Fill the medicine dropper with water. Now carefully add one drop of water at a time to the top of the penny.

Hold the medicine dropper just above the top of the penny not touching it so each new drop has to fall a short distance before it merges with the drop on the penny.

You can write down the number of drops you add if you like. How many drops of water do you think will fit on top of the penny? Watch the drop on top of the penny carefully as it grows. It should keep getting bigger and bigger until it touches the edges of the penny.

Keep adding drops refill your medicine dropper as necessary one at a time. How big does the drop on the penny get before it finally spills over the edges? Mix a small amount of dish soap with your tap water.

Now, repeat the experiment using soapy water. Do you think you will be able to add more drops or less before the liquid spills over the sides of the penny? Again, slowly add one drop at a time. How big does the drop of water on top of the penny get before it breaks and flows over the edges?

Try the experiment with different liquids or other things you can find in your kitchen.

Measuring surface tension

Make sure you have an adult's approval to use any liquids before you handle them. How do different soaps and detergents like hand soap or laundry detergent compare with one another?

What about other liquids like milk or juice? Which ones make the biggest or smallest drops? With the most or least number of drops? Try using something other than a penny to collect the droplets. What happens if you use different materials, such as the flat top of a small plastic bottle cap or a button?

Observations and results You should find that plain tap water produces a much larger, stable drop of water on top of the penny than the soapy water does.

This is because plain tap water has higher surface tension, so the surface is "stronger" and can hold together a larger drop. Making water molecules stick together less is what helps soaps clean dishes and clothes more easily.Try measuring the surface tension of other liquids, (e.g., rubbing alcohol, cooking oil).

Remember note 2j, in the Experimental Procedure section. For another method of investigating surface tension, see: Build a Motorboat Powered by Surface Tension. AeroPaks is a cost-effective, convenient way to access 8,+ SAE aerospace standards, specifications, recommended practices, and resource documents found on the SAE MOBILUS platform.

Process parameter surface tension In many production processes the surface or interfacial tension is a decisive parameter for the quality of a product. Especially within the surface technology the surface tension has become a permanent measuring and controlling variable.

2 Definitions Surface tension and surface energy F dx L Surface tension form force: The force, F, involved in stretching a film is: F = γ L γ = surface tension (constant). A Tensiometer as it applies to physics is an instrument used to measure the surface tension of liquids or pfmlures.commeters are used in research and development laboratories to determine the surface tension of liquids like coatings, lacquers or adhesives.

What is surface tension.

Get smart. Sign up for our email newsletter. Causes[ edit ] Diagram of the forces on molecules of a liquid Due to the cohesive forces a molecule 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.
3 Ways to Measure Surface Tension - wikiHow Data table for recording the results of your experiment.
Significance News Process parameter surface tension In many production processes the surface or interfacial tension is a decisive parameter for the quality of a product. Especially within the surface technology the surface tension has become a permanent measuring and controlling variable.
Background Drops dripping into water. Problems playing this file?
Surface Tension - What is surface tension - Kibron Paste a list of item s and quantities.

Surface tension is defined as the work, dW, required to expand a surface by dA. It is, thus, a direct measure of the energy needed to form a new surface of unit area, i.e. surface energy.

Surface Tensiometer :Kyowa Interface Science