Friction, Air and Water Resistance | Year 5 Science PDF Download

Understanding Friction

• Definition of Friction: Friction is a force that occurs between two surfaces that are either moving across each other or attempting to move. For instance, when you try to push a book along the floor, friction makes this task challenging.
• Direction of Friction: Friction always acts in the opposite direction to the motion of an object, which results in slowing down the object.

Why do we need friction?

• Impacts of Friction: The amount of friction is influenced by the materials of the surfaces involved. Rougher surfaces generate more friction. Friction also leads to the production of heat. When you rub your hands together briskly, you can feel them getting warmer.
• Utility of Friction: Friction serves as a beneficial force in various scenarios. It prevents shoes from slipping on pavements while walking and helps car tires grip the road surface to prevent skidding. For example, when you walk, friction occurs between the tread on shoes and the ground, providing traction and preventing sliding.
• Friction Reduction: Sometimes, it is necessary to reduce friction. One common example is using oil to decrease friction between moving parts inside a car engine. The oil acts as a lubricant, keeping the surfaces apart and flowing between them. Reduced friction results in less wear on the car's moving components and reduces heat generation.

Different forces

• Friction: Friction is a force that acts to slow down the motion of objects. It occurs when objects move through substances like water or air. For instance, when you slide a book across a table, the force that resists the motion is friction.
• Air Resistance: Air resistance is a type of friction that happens between air and an object moving through it. Objects with larger surface areas experience more air resistance, causing them to move more slowly through the air. This is why skydivers use parachutes to increase their surface area and slow down their fall.
  
• Water Resistance: Similar to air resistance, water resistance occurs when an object moves through water. When you swim, your body experiences water resistance as you move through the water. It makes it harder to move swiftly through the water.