Science

• Friction


  A contact force that acts between objects that are in contact, acting opposite to the moving object
• Gravity


  A noncontact force that pulls objects together, acts between objects that are not touching or are far from each other
• Universal Law of Gravitation


  • The mass of an object is attracted towards the mass of another object
• Gravity and mass


  The heavier the object, the more it attracts or pulls another object with lighter mass
• Gravity and distance


  The closer the object is to the ground, the higher gravitational force exists between Earth and that object
• Factors affecting the amount of friction

  • Rough surfaces have more bumps which increase friction, smooth surfaces have fewer bumps which decrease friction
• Friction and movement


  Friction resists motion, so the movement of objects subjected to friction is affected in terms of speed
• Objects move slowly on rough surfaces where friction is greater
• Objects move faster on smooth surfaces where friction is less
• Gravitational force


  The force that attracts objects with mass towards each other
• Frictional force


  The force that opposes the relative motion between two surfaces in contact
• Movement due to gravity and friction

  1. Gravitational force causes objects to accelerate downwards

  2. Frictional force causes objects to slow down or stop moving
• Gravitational force is present in many instances, such as on Earth and in outer space
• Gravitational force


  Maintains order on Earth and in outer space by keeping planets, moons, and other celestial bodies in their orbits
• The objective of the lesson is to demonstrate how air resistance slows down a falling object using Galileo's Tower of Pisa Experiment (Skydiving)
• Galileo's Tower of Pisa Experiment (Skydiving)


  1. Design a parachute using a large scarf (bandana) and a piece of string or thread, and attach a clothespin to it

  2. Drop the parachute and a second clothespin from the same height at the same time

  3. Describe the motion of the objects as they fell

  4. Re-design the parachute and repeat the procedure
• The lesson includes a review of gravitational and frictional forces and movement due to gravity and friction
• The lesson includes a performance task where students execute the Galileo's Tower of Pisa Experiment (Skydiving)
• The lesson includes feedbacking, where students can ask follow-up questions about the direction of gravitational force, how gravitational force causes motion, instances where gravitational force is present, and how gravitational force maintains order on Earth and in outer space