|
|
|
The palm glass demonstrates the contrasting effects of heat and gravity on a volatile liquid.
The glass is filled with a colored liquid, such as methylene chloride, having a low vapor point. The air in the tube ahs been partially evacuated. The apparatus is held by hand at an angle, heat from the hand providing the input of energy. A fluid with a low vapor point will evaporate with a relatively low input of thermal energy. The lowered pressure due to the evacuation of the tube enables the fluid to evaporate even more easily with the thermal input from the student’s hand. Once the fluid reaches the upper bulb, it will cool and return to a liquid state. As it flows down to the hand-held bulb under the influence of gravity, it is reheated and evaporates again.
|
|
Physics Demonstrations Home | Physics at Joint Science | Other Resources | About This Site |
