Suction Doesn't Exist

Here's a physics truth that sounds wrong: suction is not a force. When you drink through a straw, you don't pull the liquid up. You lower the air pressure inside your mouth, and the atmosphere outside pushes the liquid up the straw. The same principle explains:

• Vacuum cleaners: a fan creates low pressure inside; the atmosphere pushes air and dirt in
• Suction cups: pressing out the air leaves low pressure behind the cup; the atmosphere holds it down
• Well pumps: reducing pressure above the water lets the atmosphere push it up the pipe.