You’ve been promoted to the acoustics company! You’ve moved from the shipping department to research and development. Your first client presents you with a problem. They moved into a new condo, but the upstairs neighbours make a lot of noise. The client has tried earplugs, noise-cancelling headphones, and white noise, and yet nothing has worked. They can still hear every step their neighbours take. You recommend installing sound-absorbing material in the client's ceiling so that the neighbours’ sounds will no longer be heard. Describe the properties and structure of the material you recommend. Then explain in terms of energy and the material’s structure how it will physically absorb the sound. Maxium of 800 characters including spaces.