Tyhjiöpullot

Tyhjiöpullot, also known as vacuum flasks or thermoses, are insulated containers designed to keep their contents at a stable temperature for extended periods. They achieve this by minimizing heat transfer through conduction, convection, and radiation. The core of a tyhjiöpullo is a double-walled vessel, typically made of glass or stainless steel. The space between these walls is evacuated, creating a vacuum. This vacuum layer significantly reduces heat transfer via conduction and convection, as there are very few molecules to carry heat from one wall to the other.

The inner and outer surfaces of the double walls are often coated with a reflective material, such as silver. This coating helps to reduce heat transfer through radiation by reflecting infrared radiation back into the container, thus keeping hot liquids hot and cold liquids cold. The stopper or lid of the tyhjiöpullo is also designed to be an effective insulator, further preventing heat exchange with the surroundings. Common materials for stoppers include plastic and cork, often with an air gap or vacuum sealing to enhance their insulating properties.

Tyhjiöpullot are widely used for a variety of purposes, including storing beverages like coffee, tea, and soup, as well as keeping food warm or cold. Their effectiveness in maintaining temperature makes them popular for picnics, camping, travel, and everyday use. The principle behind their operation is a testament to applied physics, demonstrating how to control heat flow in a practical and beneficial way.