A "deed" is a legal document which records the sale or transfer of property from one party to another. Deeds often contain helpful information about the dimensions of the property, materials used in construction, and other details about the site.
In the United States, deeds are typically held by county or town "recorder of deeds" or "register of deeds." There is no web site or database that includes all deeds. Some locations make their deeds freely accessible online, but others don't. If the records are not available online, ask your professor whether they are needed for your project before you pay or travel to get them.
For properties in Pennsylvania, find the appropriate recorder of deeds web site by Googling the name of the county and "recorder of deeds" or "register of deeds." Next, look for a link to "property search." Here are deeds databases and offices for some counties near Penn State Harrisburg: