Minor repair of window frames and keeping heat in winter
In heated buildings, because of the difference between outside and inside temperature, heat is lost through walls, floors, ceilings, windows and doors. The heating system must make up this loss, so keeping heat in is important. First, loosely fitting window and door gaps are closed: they are filled with foam rubber or cotton, and 4–5 cm wide tape strips or soaked, soaped fabric strips are stuck over them; soaped fabric is easy to remove in spring. A thin rope can also be used. Small gaps may be sealed with paraffin: the wax is melted in water at 65–70 °C and squirted with a warmed syringe; hot water and wax can burn, so only adults do this. Special rubber seals are chosen by profile: tubular for the largest gaps, D- and P-shaped for medium to larger gaps, and E-shaped for the smallest (2–3 mm) gaps. Children do not climb onto windowsills; work at height is done by adults.
Draught hunt: near a classroom window or door (with an adult) hold a thin paper strip and feel the airflow. Where is it blowing? Mark the spot on a drawing. No candles or flames.