Senin, 12 Maret 2012

Chemical and Physical change
PHYSICAL CHANGE
When we mould , inflate , melt etc. its appearance may change but no new materials are formed.
These are some examples of physical changes:
inflating a balloon
cutting a cloth
melting a butter
moulding a clay


CHEMICAL CHANGE
chemical change is a change where new materials are formed
here are the examples :

burning a wood
mixing foods
cooking a food



MATERIAL AND PROPERTY
-Transparency of light
-insulator of heat
-conductor of heat
-conductivity of electricity


Choice of materials:
  1. we choose steel because its strong
  2. we choose rubber because its flexible
  3. we choose wood because its stiff
  4. we choose glass because it can help us see through
How to keep household items save , by putting them in the right

Here are the cautions :

Flammable

Corrosive
Poisonous

Toxic
BIOHAZARD
Explosive


Dangerous for the environment

so we must keep house hold items safely
  • WEATHER

CLOUDS
  • CUMULUS
Cumulus are clouds that look like cottons on the sky and is approximately 6,500ft(2,000m)
  • Stratus
Stratus are clouds that are formed like horizontal layers and its below 6,000ft(2,000m)

  • Cumulonimbus
Cumulonimbus are clouds that is vary big and tall and its altitude is 2,000m - 16,000m
  • Cirrus
Cirrus are clouds that looks like stripes in the sky it is about 2,000m over .
  • Nimbostratus
Nimbostratus are clouds that are dark and also forming layers and this cloud have an altitude that is 3,000m
FOG
Fog is a collection of liquid water droplets or ice crystals suspended in the air at or near the Earth's surface
DEW
Dew is water in the form of droplets that appears on thin, exposed objects in the morning or evening.
HAIL
Hail is a form of solid precipitation. It consists of balls or irregular lumps of ice