Approach: One
to one |
Focus:
Account for the growth
of a pine tree of immense size and weight from a small seed.
|
|
72k |
Resources: Picture
of pine tree, pine tree seed, pine cone. |
Questions / instructions:
Show the picture of a pine
tree, the pine cone, and the pine seed.
Here is a picture of a pine tree. It started growing from a very small seed like
this one, many years ago. The seed would have come out of a pine cone. The seed
weighs about 1 gram. The tree probably weighs about 3000 kilograms, or 3 tonnes.
Something happened to a little seed like this so it could grow into a very big
tree like this. Think about what could have happened.
|
|
mean
score
|
y4
1999(1995)
|
y8
1999(1995)
|
1. Try to explain
to me where the tree got all of its extra weight from since it started off as
a tiny seed.
Prompt:
How did a tiny seed weighing about 1 gram become a tree that weighs about 3 tonnes?
How did it get so much heavier?
|
Key
elements of explanation:
First, root systems and leaves develop and proceed to
absorb water, gases and nutrients from air and soil. Second, photosynthesis chemically
combines these into growing mass of the tree. |
a
|
a
|
clear,
correct explanation .
|
0
(0)
|
1
(1)
|
partial
explanation
|
6
(8)
|
14
(20)
|
identifies
basic source of materials only
|
71
(78)
|
68
(74)
|
any
other response
|
23
(14)
|
17
(5)
|
Commentary:
Year 8 students scored
only a little higher than year 4 students, and 1999 students scored slightly lower
than 1995 students. Very few students gave full explanations |