Europe is in the grip of a record-breaking heatwave. To help stay cool, people in France have been turning to an unusual solution – chalk. Here's the science behind the trend.
Here is also a video by someone who measured which is the most effective placement for a desk fan to replace the air inside with cool air in the morning hours:
What he found is it was best to place the fan 0.5 to 1 meter away from the window, and direct it to blow outside, not inside, and of course with another window open. (The reason is that due to the pressure differentials, part of the airflow is actually circulatory, similar to the magnetic flow in a coil with current, or aerodynamic flow at the tip of a wing - the fan causes the pressure to be higher in front of it, and at the edges air flows back from the high pressure zone to the low pressure zone at the back, causing a vortex).
Here is also a video by someone who measured which is the most effective placement for a desk fan to replace the air inside with cool air in the morning hours:
Best fan placement to move cool air through the house
What he found is it was best to place the fan 0.5 to 1 meter away from the window, and direct it to blow outside, not inside, and of course with another window open. (The reason is that due to the pressure differentials, part of the airflow is actually circulatory, similar to the magnetic flow in a coil with current, or aerodynamic flow at the tip of a wing - the fan causes the pressure to be higher in front of it, and at the edges air flows back from the high pressure zone to the low pressure zone at the back, causing a vortex).