1.   The heat can penetrate combustible materials, alter their composition and make them ignite at lower temperatures.

2.   This method of cooking also permits heat to penetrate evenly from both sides.

3.   The heat penetrated through the wall.

4.   On opening the door the heat penetrated the heavy black coats but they managed to withstand it, knowing they must carry out their job.

5.   It allows the heat to penetrate slowly through the egg white to the border of the yolk.

6.   The heat partially penetrates the fish, cooking the outer edges, and the fragrant oil slowly infuses the flesh.

7.   This allows heat to penetrate the cavity more quickly.

8.   While the heat can penetrate through the walls, the most direct route to the interior is through the windows.