2.11 To describe the functioning of electrostatic and gravitational

Natural sciences

Energy transfers and forces

A. forces

Educator section

Memorandum

The learners write a paragraph on the force of gravity or on electrostatic force. They can be given source books or material to consult.

Leaner section

Content

Activity: to describe the functioning of electrostatic and gravitational force [lo 2.1]

We will be finding out more about magnetism as we work through this module. So, choose one of the other two forces that are able to operate at a distance and write a paragraph to describe it and to explain how it operates.

3. measuring force

Forces can be measured by noting their ability to stretch a spiral spring or an elastic band. Many years ago, Robert Hooke, a British scientist, discovered that the stretch of a spring is equal to the force that causes the stretch. If a particular force can stretch the spring 1 cm, a force that is three times greater will stretch the spring to 3 cm. The heavier the object, the more the spring will be stretched.

If an object is heavy, we say that the force of attraction between the earth and the object is great. Weight, therefore, is the force of the attraction that the earth exerts on the object. This means that the weight of any object can be determined by measuring the stretch of a spring.

The unit that we use for measuring force (weight) is Newton (N). The name is derived from Sir Isaac Newton, one of the greatest scientists of all time. For measuring a force, we use a spring balance calibrated in Newton. We can also refer to it as a dynamometer.

Assessment

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.1: We know this when the learner recalls meaningful information: the minimum requirement is an ability to recall definitions and complex facts.