Concepts

Energy, fluid flow

Overview

When water is poured into the top bulb of the fountain, water from the middle bulb will squirt higher than the height of the fountain. Water falling from the top bulb pushes air from the bottom bulb into the middle bulb. Since the energy lost from water falling is less than the energy gained from air rising, the remaining energy (minus thermal losses) goes into pushing the middle bulb water even higher than the fountain.

This demo is also known as Heron's fountain.

Details

Equipment

• [1] Hero's fountain
• [1] Lab stand
• [1] 90-degree clamp
• [1] 2-finger clamp
• [1] Tray
• [1] Roll of paper towels
• Coloured water

Classroom Assembly

1. Set up the lab stand and clamps in the tray to catch water spills.
2. Fill the middle bulb with coloured water, leaving the upper and lower bulbs empty.

Important Notes

• The water could make a small mess.

Script

1. Pour water into the top reservoir and watch the fountain spray.

Additional Resources