<< Chapter < Page Chapter >> Page >

WEIGHT

MASS

Assessment of QUESTIONS on measuring force/weight

Were you able to apply your KNOWLEDGE?

[ LO 2.4]

Assessment

LO 1: Scientific investigations:

The learner will be able to act confidently on curiosity about natural phenomena, and to investigate relationships and solve problems in scientific, technological and environmental contexts.

This is evident when the learner:

  • plans investigations;
  • conducts investigations and collects data;
  • evaluates data and communicates findings.

LO 2: Constructing Science Knowledge:

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

This is evident when the learner:

  • recalls meaningful information;
  • interprets information;

2.4 applies knowledge.

LO 3: Science, Society and the Environment

The learner will be able to demonstrate an understanding of the interrelationships between science and technology, society and the environment.

This is evident when the learner:

3.1 is able to show an appreciation of science as a human endeavour.

Memorandum

Forces and friction

Activity

Directions of motion: to the left, right or upwards.

A force: the ability to do work; by pushing (thrust) or by pulling; friction is another example of a force.

Examples of friction: learners could name a wide range of examples, e.g. the rubber from car tyres on tar, engine parts that are not lubricated, a chair on the floor, soles of shoes against the floor, etc.

Table: accept the times provided by learners.

Questions (first set):

1. To obtain an average that would supply a more accurate indication, as conditions may not be always be exactly the same.

2. The friction is reduced: bricks alone provide the most, cardboard / perspex causes less (because of the smoother surface), a skateboard involves the least friction.

3. Lubrication, objects like small pellets that fill the space between the two surfaces reduce the surface of friction, etc.

4. Ball bearings, pistons in cylinders, toothed wheels, chains, door hinges, steering mechanism, springs, speedometer cable, a jack, etc.

Activity

Assist the learners by means of a framework according to which the report is to be assessed:

  • Planning (stating the problem, identifying sources)
  • Execution (collecting data)
  • Evaluating and communicating data
  • Appreciation of science as a human endeavour

Activity

Mass: measured in gram or kilogram

Questions:

1. 10N

2. Weight is determined by means of the attractive force of the earth, which may vary from one place to another. Mass remains unchanged.

3. Learner's answer

4. Learner's mass in kg × 10N

5. Mass × 0,6N

6. Weight signifies the force with which the earth attracts the body. It therefore has to be measured in the same unit.

7. –

8. The spring balance directly measures the earth's attractive force. A balance (pair of scales) measures by comparing an object with a known mass ('weights’) or by using a calibrated resistance (e.g. a spring).

Activity

Questions:

1. A spring

2. Friction is added to the pull

3. Marked according to acknowledged units of measure, e.g. metric units

4. 2,5 Kg × 10N = 25 Kg

5. It makes it possible to readjust the spring balance.

6. Gravitation and friction

  1. Weight: attractive force of the earth on mass

Mass: the amount of matter

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Natural sciences grade 9. OpenStax CNX. Sep 15, 2009 Download for free at http://cnx.org/content/col11069/1.1
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Natural sciences grade 9' conversation and receive update notifications?

Ask