February shadows

February shadows

Pencil and paper
Overview
Using this Resource
Connecting to the Curriculum
Marking Student Responses
Working with Students
Further Resources
This task is about making and reading a graph.

One sunny day in February a group of students measured the length of the shadow made by a stick at different times during the day. Here are their results:   

Time of day
Length of shadow, in
centimetres (cm)
10 a.m. 53
11 a.m. 37
1 p.m. 20
1.30 p.m. 18
2 p.m. 20
3 p.m. 26
4 p.m. 37

a)
Draw a line graph to show these results.
 
 
b) From the graph you have drawn answer the following questions.
 
i)

ii)

How long would the shadow length be at 12 noon? ____________ cm

What do you notice about the time of day and the length of the shadow?
 

 
 
 
 
 
c)
What causes the shadow length change during the day?
 
 
 
 
 
 
 
 
 
d)
Some students made a simple sundial using a pencil and a sheet of paper as shown above. Their sundial made the shadow E at 9:00 a.m.
Which dotted line shows where the shadow will fall at 11:00 a.m.?
  (A)
(B)
(C)
(D)		 A
B
C
D
Task administration: 
This task can be completed with pencil and paper.
Copyright: 
Graphic: copyright NZCER.
Level:
4
Curriculum info: 
Science, Communicating in science, Planet Earth
Keywords: 
astronomical systems, shadows, graph construction, graph interpretation
Description of task: 
Students use provided data on the time of day and the length of the shadow to construct a line graph. Students interpret their graph to answer three questions.
Curriculum Links: 
Science capabilities
The capabilities focus is brought about by the conversations you have and the questions you ask.
 
Capability: Interpret representations
Scientists represent their ideas in a variety of ways, including models, graphs, charts, diagrams and written texts. This resource provides opportunities to discuss 
  • the relative benefits of using tables or graphs to convey the same set of data.
  • the graph we choose to show data depends on the type of data collected (see Tables and Graphs)
 
Science capabilities: 
Interpret representations
Answers/responses: 
  Y8 (11/1998)
a)   All correct – difficult

1 error – easy


 
b) i)
ii)		 26 ± 2/or from the students graph.
Accurate statements such as the closer the time to '1:30 p.m.', the shorter the shadow (or reverse of).		 easy
difficult
c)   The Earth rotating on its axis/the Sun's rays strike at less of an angle at noon (or reverse of). very difficult
d)   B difficult
Diagnostic and formative information: 
  Common error
c) The Sun/the Sun is moving/position of the Sun – given as an answer by 53% of students.
d) Option A chosen by 34% of students.
Option C chosen by 25% of students.