Friction is not just slipperiness. It is the force that resists sliding when two surfaces meet, and its strength depends on how hard surfaces press together and how “grippy” the contact is between them. Metal on metal grabs differently than metal on glass because of what happens at a microscopic level. Iron and steel are ductile, meaning their tiny surface bumps can flatten and even micro-weld together under pressure, creating strong adhesion and generating intense heat. Glass is brittle, so instead of deforming and bonding, it chips and cracks when metal slides across it. This is why side by side tests look so dramatic. Iron on iron can gall, smear, and in extreme cases approach friction welding conditions with visible heat. Iron on glass tends to score and fracture the surface instead, producing a completely different damage pattern. The difference is not just a number on a friction scale but a reflection of how each material responds to stress at the contact point. Follow for more! 🤯 #discovery #news #science #physics #experiment