PR-0552UK Primary Science - Book 2

Measuring shadows
Light ~ Activity 2
Objectives
• recognise that light comes from
different sources
• recognise that light is needed in
order to see
Working scientifically
• Questioning
• Observing
• Predicting
• Investigating and experimenting
• Estimating and measuring
• Analysing (interpreting)
• Recording and communicating
Designing and making
• Exploring
• Making
Background information
Giant shadows are cast by the moon
and the Earth. When the moon
passes between the sun and the
Earth, its shadow falls on parts of the
Earth, creating darkness on that part
during the day. This is known as an
eclipse of the sun.
If the Earth passes between the sun
and the moon, the Earth casts a
shadow on the moon and it becomes
dark. This is known as an eclipse of
the moon.
Before the lesson
Materials needed
• Sticks, chalk (2 colours), modelling clay, tape measure, chart or book showing
pictures of eclipses of the sun and moon.
Preparation
• Organise groups and materials for each group.
The lesson
Stimulus
• Show photographs of eclipses of the sun and the moon. Discuss the enormous
shadows that are cast by the Earth and the moon during an eclipse.
What to do
• Divide pupils into small groups of three or four.
• Working in groups, tell the pupils they are going to predict and measure the
shadow of a stick throughout the day.
• Pupils place a stick into a lump of modelling clay.
• Pupils place their stick in a sunny spot on the ground where the shadow can
be traced.
• Record the shadow by tracing it with chalk and measure the length of the
shadow. With the other coloured chalk predict the position and the length of the
next shadow in 30 minutes’ time. Continue to do this throughout the day.
• Pupils present their results in a bar graph on their worksheet. (Teachers will
need to direct pupils to complete the vertical axis according to the longest
shadow recorded and to fill in the times of the day on the horizontal axis.)
• Discuss the results.
After the lesson
Answers
• Pupils’ results should show the shadows are longest in the early morning and
late afternoon and shortest at noon. The length of the shadow changes as the
sun appears at different angles in the sky. At noon, when the sun is closer to
directly overhead, there is very little shadow. The position of the sun changes
as the Earth rotates on its axis.
Viewing Sample
Additional activities
• Pupils think of other ways to record the position of the sun.
Display ideas
• Cut out graphs and glue onto card. Pupils record their findings below and display
on the wall.
40 PRIMARY SCIENCE ~ Prim-Ed Publishing ~ www.prim-ed.com