tree ring.ppt

文档介绍：Lesson Eighteen
Tree Rings
Moscow
snowy
Sydney
cloudy
Singapore
sunny
Beijing
windy
What’s the weather like today?
Free Talk!
What was the weather like yesterday?
How?
What will the weather be like tomorrow?
Tree rings
Do you want to know something about the history of weather? Don’t . Don’t .
is more important. Some weather reports go back only one century, but some trees can show us an exact record of the weather even further back.
How can we know the weather?
look at the sky
look for old weather reports
How?
Looking at the tree rings
is also expected that little sunlight or rainfall would limit the growth of a tree. The change from a favorable to an unfavorable climate can be seen by reading the tree rings in a tree trunk. To find out the weather of ten years ago, count the rings of a tree trunk from the outside to the inside. If the tenth ring is far from the other rings, then we are sure that lots of sunny and
It is clear that a tree would grow best in a climate with lots of sunlight and rainfall. It
rainy weather happened. If the rings are close together, then the climate was bad for the tree.
Q1:
In what climate would a tree grow best?
Q2: What would happen
if there is little sunlight and rainfall?
Q3:How can we see the change
from a favorable to an unfavorable climate?
Q4:
How can we find out the weather of ten years ago?
sunlight
rainfall
lots of
little
far from
Close together
1. Which tree lived in a sunny and rainy place?
2. Which tree lived in a bad weather?
(A)
(B)