• Cups of water (one per pair)
• Pennies (10 per pair)
• Paper towels
• Eye droppers (optional)
• Recording sheet

Gather all materials in advance. Test the experiment yourself. Prepare simple recording sheet with prediction and result spaces. Plan transition back to regular instruction.

1. Announce: 'Two-minute lab! Clear your desks. Materials coming.'
2. Distribute cups of water filled to the brim and pennies.
3. Question: 'How many pennies can you add before the water overflows? Write your prediction.'
4. Students carefully add pennies one at a time, counting.
5. When water overflows, record the result. Most students drastically underestimate.
6. Class data collection: What was your prediction? What was your result?
7. Observe the water surface before overflow: What do you notice? (Bulging dome shape)
8. Quick explanation: Surface tension - water molecules stick together like a skin.
9. Connection to lesson: 'Today we're learning about molecular forces. This is one example.'
10. Clean-up routine: 30 seconds, specific jobs assigned.

Pair fine motor challenges with steady-handed partners. Provide visual prediction scale. For advanced students, ask them to design a follow-up experiment testing surface tension.

Compare predictions to actual results. Listen to explanations for accuracy. Follow-up quiz questions assess conceptual understanding beyond just the activity.