Does anyone know what I can say for the title in my own words or the background research?
You can use this as a title for the physics investigation: To show the different effects of a change of (a) material type and (b) material thickness on the amount of sound that can be blocked by a range of materials.
On the background research section, you must mention at least one website/book/person etc., and make a solid prediction of what the result will be.
Investigate and compare the quantitative effects of changing (a)
material type and (b) material thickness on the level of sound
insulation provided by a range of materials.