Inventions can be big or small, complex or simple, but what makes them incredible is their ability to solve problems and make our lives easier. Here are some simple but incredible inventions that have had a big impact on the world:

1. Post-it notes: Post-it notes were invented by Spencer Silver, a scientist at 3M, in 1968. He was trying to create a super-strong adhesive, but instead, he created a weak one that could be easily removed. It wasn't until a few years later that another 3M scientist, Arthur Fry, realized the potential of the adhesive and came up with the idea for the Post-it note. Today, Post-it notes are used all over the world for everything from reminders to creative brainstorming.
2. Ziploc bags: Ziploc bags were invented by Borge Madsen, a Danish engineer who worked for Dow Chemical, in the 1950s. He came up with the idea for a plastic bag with a resealable zipper that could keep food fresh for longer. Today, Ziploc bags are used for all sorts of things, from storing food to organizing small items.
3. Paper clips: The paper clip was invented in the 1890s by Johan Vaaler, a Norwegian inventor. He wanted to create a simple, inexpensive way to bind papers together, and the paper clip was born. Today, paper clips are still used for their original purpose, as well as for all sorts of creative crafts and DIY projects.
4. Safety pins: Safety pins were invented in 1849 by Walter Hunt, an American inventor. He created the safety pin as a solution to the problem of straight pins, which could easily fall out and cause injury. Today, safety pins are used for everything from fastening clothing to emergency repairs.
5. Ballpoint pens: The ballpoint pen was invented in the 1930s by Laszlo Biro, a Hungarian journalist. He wanted a pen that could write more quickly and cleanly than a fountain pen, and he came up with the idea of using a small ball bearing to distribute ink onto paper. Today, ballpoint pens are used by millions of people all over the world.
6. Clothes hangers: Clothes hangers were invented in the 1860s by Albert J. Parkhouse, an employee at a wire company in Michigan. He came up with the idea for a curved piece of wire that could be used to hang clothes and keep them wrinkle-free. Today, clothes hangers are used in every household and clothing store.
7. Velcro: Velcro was invented in the 1940s by Swiss engineer George de Mestral. He was inspired by the way burrs stuck to his clothes and came up with the idea of using tiny hooks and loops to create a fastening system. Today, Velcro is used in everything from shoes to clothing to medical devices.