How do you demonstrate surface tension of water?
To demonstrate surface tension, place a small amount of water (~1 cm deep) in a shallow glass or plastic dish (or plate), and place the dish on an overhead projector. Turn on the projector, and carefully place a needle on the water surface so that the needle floats.
What is an experiment that tests surface tension?
In the Sink or Swim experiment, you’ll learn how adding one variable to water will change the amount of surface tension the water has. You’ll see that anything you add to water may quickly affect whether something sits on water or not.
How do you find surface tension in an experiment?
Measuring Surface Tension with a Balance Beam. Define the equation to solve for surface tension. In this experiment, the equation for surface tension will be determined by the equation F = 2sd. F is the force in newtons (N), s is the surface tension in (N/m), and d is the length of the needle used in the experiment.
How does water purity affect surface tension experiment?
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.
What can increase the surface tension of water?
The surface tension of water, for example, will increase when highly soluble impurities are added to it. When detergent is added to water, it decreases the surface tension of the water. Compounds that lower water’s surface tension are called surfactants, which work by separating the water molecules from one another.
What are some examples of surface tension?
Examples of Surface Tension
- A Drop of Liquid.
- Soaps and Detergents.
- Washing with Hot Water.
- Clinical Test for Jaundice.
- Water Striders.
- Capillary Action.
- Formation of a Meniscus.
- Bubbles.
What are the methods of measuring surface tension?
Surface tension can be measured with force tensiometer using Du Noüy ring or Wilhelmy plate. Or with optical tensiometer using the pendant drop method.
Why does the surface tension of rice decrease?
The y-axis of your graph can represent temperature and the x- axis can represent number of rice grains. Surface tension is less if fewer grains of rice are needed to upset the aluminum. Which has less surface tension – saline or pure water?
How to calculate the surface tension of water?
Using a hot plate, heat the water until it is 35°C. If you do not have a hotplate, use a microwave, heating the water for 5-second intervals and checking the temperature after every 5 seconds. Repeat step 5. Try this again when the water is 40°C, 45°C, 50°C, and 55°C. Graph your results.
What is the interface tension between water and oil?
When there is contact between the surfaces of two liquids like water and oil, it is called interface tension. The molecules in a liquid (e.g. water) are drawn together by intermolecular forces known as Van der Waal forces. The molecules on the surface of the water are not surrounded by water molecules Paddy Heaton 9SC3 3
Which is an independent variable of surface tension?
Independent variable: The temperature of the water Dependent variable: Surface tension Controlled Variables: Room temperature, water depth, floating object, water salinity, water quality, air pressure Control Test: Water from the tap left for ten minutes to achieve room temperature Materials Used