Wetting, capillary phenomena Presentation

Properties of the surface layer of the liquid. 

Wetting, capillary phenomena

Learning objectives

To define the liquid surface tension coefficient using different techniques

Knowledge actualization

What is the process of transition from a gaseous state of a substance to a liquid?
What is the name of the reverse process?
What factors determine the rate of evaporation of a liquid?
What steam is called saturated?
Why does the saturated steam pressure not depend on the volume?

Knowledge actualization

What steam is called unsaturated?
What temperature is called critical?
What process is called boiling.
Why does the temperature remain constant during boiling?
How does the boiling point depend on the air pressure above the liquid?

Group 1:

1. Get acquainted with the article "Surface tension".
2. Answer the questions:
- What phenomenon is called surface tension?
- Where can I observe the surface tension phenomenon?
- What values ​​characterize surface tension?
3. Run the experiment:
"Study of the shape of a liquid in natural conditions."
Devices and materials: aluminum, copper, glass, paraffin plates; sunflower or olive oil; alcohol solution in water, wire, syringe or glass tube.

Group 2:

1. Get acquainted with the article "Capillary phenomena"
2. Answer the questions:
What are capillary phenomena?
Where can I see capillary phenomena?
What values ​​characterize capillary phenomena?
3. To perform the experiment: "Study of the dependence of the height of the rise of the liquid on the diameter of the capillary, on the kind of liquid.
Instruments and materials: glass tubes of different diameters, water, ruler, transparent rectangular vessel.
After completing the assignments, each group will present another progress report. The second group asks questions and makes corresponding entries in a notebook.

Lab work

Health and safety!!!