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 