please could someone help explain the mechanism of a convection current as I keep finding conflicting explanations. Is a convection current caused by differences in density or differences in pressure? Most seem to say it is caused by differences in density (more specifically buoyancy) since you cannot get a convection current in zero gravity. However, could someone help explain the following:
If you take a house on a cold winters day then hot air in the house will rise due to differences in density and some of this air will find some way of escaping out the top of the house. When this warm air escapes, as far as I know, this causes cooler air from outside to be drawn in neat ground level (e.g. under your door). Surely this mechanism is caused by pressure differences? Why else would the cold air come inside the house? If it didn't then you would eventually create a vacuum no? I know it's not possible but if you completely stopped hot air leaving the top of your house would this completely stop drafts at the bottom of the house since a draft is just cold air coming in to replace the escaping hot air? Or vica versa, if you completely blocked cold air coming into your house at ground level would this have the knock on effect of stopping hot air escaping near the top?
Thanks to anyone who can help out!