Addison Wesley Science And Technology Grade Student Book !new! -
Reluctantly, Leo cracked open the book to Unit D: "Heat in the Environment."
Maya looked disappointed. His parents looked impressed. addison wesley science and technology grade student book
The first section was on thermal energy transfer. Conduction, convection, radiation. A diagram showed how heat moved through solids, liquids, and gases. Leo’s eyes landed on a sidebar: "Mystery Sound? Check for thermal expansion." Reluctantly, Leo cracked open the book to Unit
He presented his findings to his family at dinner, flipping through his Addison-Wesley book to the section on heat transfer. "It's not a ghost," he announced. "It's simple physics. The wall is like a giant bimetallic strip in a thermostat. Day and night temperatures make it groan." Conduction, convection, radiation
His problem was the Whispering Walls. For three nights, a low, mournful hum had drifted from the ancient brick wall behind his bedroom. His little sister Maya claimed it was a ghost. His parents shrugged and blamed the furnace.
His data was clear. The greater the temperature drop, the louder the sound. The bricks were contracting at a slightly different rate than the steel beam hidden inside the wall, rubbing together and vibrating like a giant, slow cello string.
