Isn’t that convection? The air coming in to contact with the hot surface rapidly heats and rises and cooler air rushed in to replace it. I thought that’s what

Isn’t that convection? The air coming in to contact with the hot surface rapidly heats and rises and cooler air rushed in to replace it. I thought that’s what we saw as per your instructions? I thought air (mostly nitrogen and oxygen) is mostly transparent to infrared radiation?