What are the key differences between a bike helmet and a ski helmet, and how do these differences impact their respective safety and performance features?

A key difference between a bike helmet and a ski helmet is their design and intended use. Bike helmets are typically lighter and more ventilated for airflow during physical activity, while ski helmets are heavier and provide more insulation for cold weather. These differences impact safety and performance as bike helmets prioritize impact protection and ventilation, while ski helmets focus on warmth and protection from the elements.