19. Else

• 19.1. Extinguishing without water
• 19.2. Air is not nothing: weighing air
• 19.3. Two springs, series or parallel?
• 19.4. Force and motion with a bowling ball
• 19.5. Upward dripping
• 19.6. Curve ball
• 19.7. Colliding balls
• 19.8. A balloon that can do everything
• 19.9. Transit of a planet
• 19.10. A light bulb as hot as the sun?
• 19.11. DNA
• 19.12. Gauss’ rifle
• 19.13. Falling spring
• 19.14. Radioactive decay - A simulation