Hero's Engine

The flask reaches 100°C and contains pressurized steam. Do not touch during or immediately after operation — allow several minutes for cooling. Do not overfill with water. Keep flammable materials away from the torch.

Wear safety goggles. Consider eye protection for students in the first few rows — steam jets can redirect unexpectedly.

Glass under thermal stress can crack or shatter. Inspect for cracks before use and heat gradually. Have cleanup materials ready.

Purpose

Demonstrates Newton's third law and rocket propulsion in a rotational context. A suspended flask with tangential exit tubes spins when the water inside boils — escaping steam exerts a reactive force that generates torque. Connects thermodynamics (phase change and energy conversion) with rotational dynamics.

Round-bottom glass flask with two horizontal glass exit tubes, suspended by string from a horizontal rod between two bench clamp stands; a BernzOmatic propane torch sits below on the bench

Figure 1: Hero's Engine: a round-bottom flask with tangential exit tubes, suspended from a rod between two bench clamp stands. The propane torch heats the flask from below.

Propane Torch

1

Warning: Heat and Pressure Hazards

Warning: Eye Protection Required

Warning: Glassware Hazard

Purpose

Safety Warnings

Warning: Heat and Pressure Hazards

Warning: Eye Protection Required

Warning: Glassware Hazard

Purpose