If you have any interest in computers and have studied the early days you know Rear Admiral Grace Murray Hopper, PhD, USNR
, one of, if not the first to "debug" a computer.
Several of her lectures are on video, and even if you aren't really a computer person, she is a great teacher. She probably has more "firsts" than anyone else in the field of computer science.
"You manage things, you lead people. We went overboard on management and forgot about leadership. It might help if we ran the MBAs out of Washington."
One of the most useful tools for demonstrating speed was her 30 centimeter [approximately 1 foot] pieces of wire that she used to demonstrate computing speed. That's how far light travels in a nanosecond.