INTERACTIONS OF FORCES

  • Magnets can exert a push or a pull
1) Identify the characteristics of magnets
  • Can be made of iron or steel.
  • Have two poles. A freely suspended magnet comes to rest pointing in a North-South direction.
  • Unlike poles attract and like poles repel.
  • Magnets attract magnetic materials.
2) How to make a magnet
Stroke method: 
  • Using one end (pole) of a magnet, stroke it on a magnetic object eg iron rod.
  • Repeat process for about 15 times using the same end in the same direction.
  • Test the newly made magnet on some iron fillings or paperclips. If it attracts the fillings, the iron rod is magnetized and can act as a magnet.
  • The end of the rod which last touched the North pole of the magnet, becomes the South pole and vice versa.

​Electrical method:
  • Using a battery, electrical wire and an iron rod.
  • Coil the iron rod with the electrical wires for about 5 rounds and connect the ends of the wire to the battery.
  • The iron rod is then ready to be used as a magnet.
  • This type of magnet is called an electromagnet and loses all its magnetism when there is no current in the wire or it is removed from the coil.
  • Magnets made this way can vary its strength by the number of coils around the magnet and the number of batteries used.
3) Effects of a force
  • can move a stationary object.
  • can speed up, slow down or change the direction of motion.
  • can stop a moving object.
  • ​may change the shape of an object.
4) Different types of forces
  • magnetic force
  • gravitational force
  • elastic spring force
  • frictional force
5) Effects of fiction on the motion of objects
  • Slow down moving object.
  • Stop moving object.​
6) Effects of forces on springs
  • When we pull a spring it is stretched.
  • When we push a spring it is compressed.

INTERACTIONS WITHIN THE ENVIRONMENT

7) Identify the factors that affect the survival of an organism
  • Physical characteristics of the environment eg. temperature, light and water
  • Availability of food
  • Type of other organisms present eg. producers, consumers, decomposers
8) Effect on organisms when environment becomes unfavourable
  • Adapt and survive
  • Move to other places
  • Die
9) Trace the energy pathway from the Sun through living things
  • Producers absorb light energy from the Sun and convert it into chemical energy in the form of glucose using the process photosynthesis.
  • Consumers get the energy from the glucose by consuming the producers.
  • Decomposers break down dead organisms and releases nutrients into the air as carbon dioxide. Carbon dioxide is taken in by producers for photosynthesis.
10) Differentiate among the terms
  • Organism:  is a living thing
  • Population:  a group of plants or animals of the same kind, living and reproducing at a given place and time.
  • Community:  many populations living together in a particular place.
11) Adaptations
  • serve to enhance survival and can be structural or behavioural.
  • cope with physical factors
  • obtain food
  • escape predators
  • reproduce by finding and ttracting mates or dispersing seed/fruits
12) Man's impact
  • Positive:  conservation, reforestation
  • Negative: depleting natural resources, deforestation, pollution (land/water/air), global warming.
Summary

You should know:
  • there are interactions among man, living and non-living things n the environment
  • man can make positive or negative impacts
  • man plays an important role in conservation to ensure continuity of life and availability of resources