Force and Motion

Unit Overview

This Unit facilitates students to understand the characteristics of object motion and the principles behind it in a systematic manner. Through daily life examples (e.g. a pedestrian's walking speed, a car's speed), students will learn the relationship between speed, distance, and time, and be guided to understand how acceleration or deceleration affects motion. Students will also learn to differentiate between contact forces (e.g. friction, elastic force) and non- contact forces (e.g., gravity, magnetic force), and comprehend that in the physical world, forces and reaction forces occur in pairs, impacting an object's motion. In addition, teachers can guide students to explore the factors that affect friction through daily examples. Students can conduct experiments to compare the friction of different materials, and present the analysis results through appropriate methods. Students will also learn the relationship between gravity and mass, and predict whether the gravity experienced by objects with the same mass would differ on different planets. This Unit also facilitates students to learn about the relationship between pressure, force and area. Students will learn how air pressure and water pressure change with height or depth, and give examples of applications of pressure in daily life. Teachers may further guide students to use the concept of particle movement to explore the relationship between air pressure and temperature, propose scientific explanations, and understand the concept of “evidence and models”. Through a series of practical activities, students will be able to make scientific inferences, connect theories with daily life phenomena, and explain various observations. Teachers can also design other appropriate learning and teaching activities to allow students to develop and master the following skills: a) using specific data to induce a general trend, conclusion or model b) making inference to the best possible explanation to the observed phenomenon c) formulating a hypothesis based on observed phenomenon d) identifying independent variables, dependent variables and control variables e) setting up a control experiment to avoid confounding factors and identify causation f) choosing from alternative experimental methods or improving the method for a scientific investigation g) commenting the reliability of a scientific measurement or a scientific investigation h) using scientific formula for scientific inference i) identifying outliers and handling data from repeated measurements to assess the uncertainty incurred