Northwestern has a very comprehensive general engineering program that exposes you to almost every discipline in the engineering school over your first four quarters. The program is called Engineering First, and is composed of four Engineering Analysis (EA) classes, where you get introduced to the analytical part of engineering in many of those disciplines, and Design Thinking and Communication (DTC), where you learn the basics of engineering design and the design process. Personally, I found three of the four EA classes to be very interesting, and DTC is the reason I switched to engineering from liberal arts.
Here’s a link to the Engineering First curriculum: http://www.mccormick.northwestern.edu/academics/undergraduate/core-curriculum/engineering-first.html
All majors additionally have a couple class slots dedicated to Basic Engineering classes; through those, you can get a feel for different majors before you commit to a major, or even if you choose a major but are unsure if you chose correctly.
Plus, its super easy to switch between majors, especially during freshman year, in case you change your mind.