Living or Not?

This demonstration creates moving “critters” by adding a drop of modeling glue to water in a Petri dish. The glue droplets move in an amoeboid fashion and appear to respond to food (wood shavings), sparking discussion about the characteristics of life and what it means to be “alive.”

1. Place a Petri dish on an overhead projector.
2. Fill it about halfway with tap water.
3. Release a small drop of modeling glue onto the water’s surface (use a pipet to disguise the source).
4. Prepare “food” by shaving wood and graphite from a pencil. Sprinkle near the glue droplet.
5. Observe the glue “critter” as it moves, changes shape, and seems to eat the shavings.
6. Add more glue droplets to observe how they interact.
7. When the critters stop moving, discuss with students whether they showed characteristics of life.

My Favourite Experiment - David Haller - Living or Not:

📄 Glue Monsters—Are They Alive - Flinn Scientific: https://www.biologyjunction.com/images/misc/glue%20monsters.pdf

• Use different colored backgrounds or lighting to enhance the visibility of movement.
• Have students list which characteristics of life the glue monster appears to display, and which it does not.

• Vapors are caustic - use in a well-ventilated area and avoid inhalation.

• What characteristics of life did the glue monsters appear to show? (Movement, response to stimuli, feeding-like behavior.)
• What characteristics of life did they not show? (Growth, reproduction, cellular structure.)
• How does this activity challenge us to define what it means to be alive?
• Why is defining life sometimes considered a philosophical issue as well as a scientific one?