Addison Wesley Science And Technology Grade Student Book -

Case closed.

A spark lit up in Leo’s brain. Not a ghost. A temperature change. addison wesley science and technology grade student book

Thermal expansion? He read on. When materials heat up, their particles vibrate faster and take up more space. When they cool down, they contract. This movement, especially in large structures like bridges or old brick walls, could create stress—and sometimes, sounds. Case closed

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. they contract. This movement