Making a alter

Page Content

This focus thought is explored through:

  • Contrasting student and scientific views
  • Critical teaching ideas
  • Teaching activities

Contrasting educatee and scientific views

Student everyday experiences

Understandably, children view the world of moving objects in quite simple terms. This is oftentimes in contrast to the precise and complex terminology and definitions used by science.

Some of these ideas are explored in earlier focus ideas: Pushes and Pulls, What is a force?

Students' everyday experience of moving objects is that they need a abiding push to keep them moving. This experience is reinforced by cycling, roller skating and only sliding heavy objects beyond a floor. Without a constant force objects in a friction filled world do somewhen slow down and cease.

These experiences support the common view that constant motion requires a constant force and that the greater the amount of motility, the greater the force required to maintain it.

Research: Gunstone & Watts (1985)

Scientific view

There are often many forces acting on an object. Some, such as those arising from frictional interactions when surfaces slide over each other, are often not thought of as forces in everyday life.

For stationary objects and objects moving with a steady speed in a straight line, all the forces cancel each other out, i.e. they are counterbalanced.

If the forces are not balanced then the motility of the object changes. It may speed upwards, wearisome down and/or alter direction.

For a given force, an object with a small ma​ss will feel a greater change in move than an object with a larger mass.

A large unbalanced strength on an object volition produce a bigger change in motility than a smaller unbalanced force on the same object. This is consistent with the common experience that big massive objects require large forces to make them motion, speed up or change direction.

Critical teaching ideas

  • We tin draw how something moves by using terms such as 'at rest', 'constant speed', 'speeding upwardly' and 'slowing down'.
  • A forcefulness tin speed up or deadening down an object.
  • A force can modify the direction in which an object is moving.
  • A bigger force on an object will produce a bigger change in the motility.
  • A heavier object requires a larger force than a lighter object in order to undergo the aforementioned change in move.

Explore the relationships between ideas about forces in the Concept Development Maps – (Laws of Motion, Gravity)

Students should be helped to describe changes in motion using terms such equally 'getting faster' and 'slowing down'. They should as well be assisted to identify and determine when an object undergoes a change in direction. This should exist seen by students as a change in move of equal importance to a modify in speed.

Provide teaching experiences that aid them sympathise that in social club to modify how something is moving information technology needs to be given a push or a pull (i.e. a force).

Educational activity activities

Open up give-and-take via a shared feel

A young girl attempting to hit a ball with a yellow plastic cricket batStudents should be given opportunities to notice many kinds of moving things, and be asked to describe changes in motion such as speeding up, slowing down or irresolute directions. Observations tin can exist made in the playground, from video clips or at a sporting venue.

Focus student attention on disregarded item

Students tend to focus just on whether something is moving or non moving. Utilise the above discussions to focus their attending on the difference betwixt abiding motion and irresolute motion. Situations where students have firsthand experience of changing motion such as starting, stopping and turning empty and loaded supermarket trolleys are particularly useful.

Promote reflection on and clarification of existing ideas

Students demand experiences that assist them to focus on the furnishings of pushes and pulls and how these tin consequence in objects speeding upward and slowing downwardly (such as observing a person on a swing, moving assurance or someone sitting on a skateboard). They also need to experience forces that change the direction of things that are moving (such as changing management on a bike or of a ball rolling along the ground).

Challenge some existing ideas

Students can be set the difficult task of changing the direction or speed of a rolling marble by directing an air stream at it by blowing through a straw. They should endeavour changing its speed and its direction.

Students can stretch a short elastic 'daze cord' to pull forth a student on a skateboard. By keeping the extension of the 'shock cord' the same length, they are keeping a steady pulling force on the student and very soon the skateboarding student volition be moving very quickly. Have the students investigate how a change in the direction of the pulling force will modify the skateboarder's management of move.

Students should experience the force required to stop objects of unlike weight such as moving balls of different weights (such equally a medicine ball, a basketball game, a shot put, a billiard brawl, a golf ball and a lawn tennis brawl).

Collect bear witness/data for analysis

Students should exist encouraged to remember well-nigh means of measuring and recording speed and the size of forces. Encourage students to explore changes in movement with respect to road safety. They can investigate stopping distances of bikes moving at different speeds and on dissimilar surfaces. They tin explore ideas of the difference in strength required to stop a truck and a motorcar moving at the aforementioned speed.