"How  does  it work?" Ron asked curiously, though he visibly regretted his decision almost immediately when Hermione launched into a detailed explanation as to the physics behind static electricity. His eyes flicked to Harry’s in a plea for help when Hermione started talking about electrons, and he looked likely to cry when Hermione pulled her cardigan free from her bag and rubbed it vigorously on his head to demonstrate the effect in his hair. Harry could only smile; he hoped they would never change.