Engineering on Instagram: "Hand Pump: How It Lifts Water In this video, we explain how a hand pump uses simple parts and pressure differences to pull water up from below ground in just a few easy strokes. 📌 What you’ll learn in this video: ✔ How the piston and valves move water upward. ✔ Why atmospheric pressure and priming matter. ✔ Common problems and simple maintenance tips. A hand pump is a simple displacement pump you operate by hand. When you pull the handle up, the piston inside the cyli