Do some research.  Read all about past and current inventions that have had a great impact on society.

• The 50 Most Influential Gadgets of All Time is a fascinating report/slideshow just published by TIME.
• The 50 Greatest Breakthroughs Since the Wheel is from The Atlantic.
• 7 Amazing Teenage Inventors is from TIME.
• Here’s a U.S. Invention Timeline.
• The History Channel has a number of short video clips on different inventions.
• How Stuff Works has quite a few short videos on inventions.
• Watch these twelve lessons in a TED-Ed series titled Moments of Vision. The videos in the series teach short lessons about inventions that have “changed the world” in serious and not-so-serious ways.
• 5 Inventions that Changed the World