Shower caps and smoke detectors

So we decided to heat up the left over fish and chips. Got the stove figured out, and remembered to put the shower cap over the smoke detector. Turned on the stove and in about 3 minuted the smoke detector went off – it is really loud. Opened the door and flapped a towel at it, and then it stopped, only to go off again 2 more times. Cold fish sounds good. I guess we didn’t use the shower cap right.