In This Lesson
WHAT WE HAVE DONE
Related the story of Valli's first bus ride.
WHAT You Can Do
1. The students should be given two or three days to collect old (used) tickets from
their friends, relatives and acquaintances: they could be bus tickets, train tickets,
plane tickets, cinema tickets, tickets to cultural events, etc. By the time they finish
the lesson they should be able to get a good collection in place. Get them to make
a collage using as many as possible of the tickets collected, on a sheet of poster
paper. This can then form the basis for many interesting activities: classification
according to type of tickets (for what?) or price (how much?), etc; the most desirable
tickets, the tickets no one wants, etc. - let students think of more ways to classify
them. Get students to write a paragraph with the collage as base, and their
imagination as guide.
Answers
Chemical weathering typically increases as temperatures rise and rain falls, which means rocks in hot and wet climates experience faster rates of chemical weathering than do rocks in cold, dry climates.
Physical weathering occurs more often in cold climates, because the different minerals within rocks expand and contract at different rates when they are heated and cooled. Repeated heating and cooling cycles eventually cause rocks to fracture. Desert and mountain climates experience a wide range of temperatures from low to high during a day and night, which accounts for the breakdown of rocks known as physical weathering.
Biological weathering occurs when living organisms break up rocks. Tree roots, for example, can fracture rocks in the same way they buckle pavement. Warm, humid climates are most favorable to life. Contrast the rich diversity of life in a rainforest, for example, with the scarcity of life in the dry Sahara or the frigid Antarctic. Consequently, rates of biological weathering are most rapid in warm humid climates like those in tropical regions.