Drinking Bird

The drinking bird is a classic science demonstration that appears to move endlessly by dipping its beak into a glass of water and bobbing back up again. In reality, it operates through heat transfer and changes in vapor pressure, showing the conversion of thermal energy into mechanical motion.

1. Place a drinking bird toy on a flat surface beside a glass of water.
2. Dip the bird’s head and beak into the water so that they become wet.
3. Set the bird upright and observe as it begins to rock back and forth.
4. The bird will eventually tip forward and dip its head into the water again, continuing the cycle automatically.
5. Observe the pattern of movement and note how temperature and humidity affect the rate of motion.

How does a drinking bird work? - Make Science Fun:

The Engineering of the Drinking Bird - engineerguy:

📄 How drinking bird toys work - Fizzics Education: https://www.fizzicseducation.com.au/150-science-experiments/heat-experiments/how-drinking-bird-toys-work/?srsltid=AfmBOoptx0twnFaQels32lt7blZDSAbx0C51_TizXWGDSeLLgjWOb4du

• Try using warm or cold water to see how the temperature affects the bird’s speed.
• Test the bird in rooms of different temperatures or humidity levels.
• Use a fan or hair dryer to cool or warm the bird and note the effect.
• Place two drinking birds side by side and compare their motion.

• Handle the bird carefully - its glass body is fragile and can break if dropped.
• Avoid exposing the bird to open flames or direct sunlight for extended periods, as the internal liquid is volatile.
• Keep out of reach of very young children.

• What causes the bird to move up and down? (Evaporation of water from the bird’s head cools the vapor inside, lowering pressure and drawing liquid up the neck, shifting the balance and causing it to tip.)
• Why does the bird “drink” repeatedly? (After tipping, the liquid returns to the lower bulb, restoring balance and allowing the cycle to repeat.)
• Is the drinking bird a perpetual motion machine? (No—its motion is powered by heat energy from the surrounding air and water evaporation.)
• How does temperature affect the motion? (Warmer air increases evaporation and speeds the bird’s cycle, while cooler air slows it down.)
• What real-world processes does this model? (It demonstrates thermodynamic cycles, similar in principle to heat engines.)