Day and night Session

```Science Year 5
Physics Strand: Earth and space
Session B
Programme of study: Use the idea of the Earth’s rotation to explain day and night and the
Day &amp; night
Working
scientifically
Plan scientific enquiries
Record data and results of increasing complexity using graphs
apparent movement of the Sun across the sky
Posts, sticks, rulers, metre sticks, chalk, compass for measuring direction, materials to make
Whole class teaching: (links to Session 5, Our Planet Theme, Adventure in Space Topic &amp; Session 7a, Mayas &amp; Aztecs
Theme, The Americas Topic)
Remind chn that the Sun is at the centre of our solar system (heliocentric) &amp; is very important for life on Earth. Write Does the
Sun move across the sky? on f/c. Discuss this with chn: who agrees or disagrees? Tell chn that the Earth rotates on its own axis
(for many years people thought the Earth did not rotate). How long does it take? 24 hours/a day. It rotates from West to East
in an anticlockwise direction, making the Sun appear to rise in the East and set in the West at 1000miles/1600km an hour
approx. (and apparently move across the sky). Look at websites showing animated rotation, e.g.
http://www.onr.navy.mil/focus/spacesciences/skyobserve/motion1.htm,
http://www.childrensuniversity.manchester.ac.uk/interactives/science/earthandbeyond/soonmoonearth/ or
http://www.fearofphysics.com/SunMoon/sunmoon1.html. In fact the Sun does move - it rotates anticlockwise on its own axis,
but different parts of the surface rotate at different speeds because the Sun is not solid but instead a giant ball of gas &amp;
plasma. Movement of sun spots (see Session E) allows us to see this rotation from Earth. Also the Sun orbits round the centre
of the Milky Way (NB chn do not have to remember these facts about the Sun). However the Sun does NOT orbit the Earth as
people used to think a long time ago.
Resources needed
Group activities:
Class activity: Safety: Tell chn that they must not look directly at the sun, not even with sunglasses on, as this can damage
their eyes. Carry out a day long investigation to demonstrate this practically: Stand a stick/rounders post in playground – mark
position of shadow using chalk recording its length and direction using a compass. Back in classroom begin to graph data being
collected, i.e. length of shadow against time as a line graph, direction (&amp; length) can be shown as a diagram that shows both
the length (drawn to scale &amp; labelled with time) &amp; direction from a central point (chn could carry out this activity at a different
time of the year as well &amp; then compare results: comparing Summer and Winter time results is a v useful exercise). Using
session resource, make a sundial OR sun clock. Hold a pencil upright somewhere along the North/South line to cast a shadow.
Afterwards chn can take it outside on another sunny day to tell the time. As Earth rotates the shadows change in length and
shape. On the hour, mark the location of a shadow. If you returned to the same object in 24hrs, the shadow should be in same
place (roughly). Look at real sundials and images of others (session resources). Do they work? What are the advantages and
disadvantages of a sundial? What happens at nighttime? Facing away from Sun, etc? Watch short clip at
http://www.bbc.co.uk/learningzone/clips/sun-and-shadows/6664.html. Also see simple online version at
Using a bright torch as source of the Sun’s light, hold a small globe in front of the beam. Model how as the Earth turns
anticlockwise it casts half the world in shadow and darkness. The Sun appears to rise from the East giving us daylight! Ask chn
to consider how many hours we spend in darkness in a 24hr period, how many hours of daylight are there? How can we find
out? Show chn weather pages of newspapers where hours of sunrise and sunset are listed. Why might it be important to
know such information?
How does the length of the day change throughout the year from one season to next? Ask chn to draw graphs (data - session
resources) to show how hours of daylight change over a year – Which month has the most? Which has least? When is day
length the same as night time? Link to summer &amp; winter solstices &amp; spring &amp; autumn equinoxes.
Independent activity: Using session resources ask chn to graph the annual data for daylight hours.
Independent activity: Visit the website below to investigate how day length varies during the year:
http://www.childrensuniversity.manchester.ac.uk/interactives/science/earthandbeyond/sunrisesunset/.
Visit http://www.schoolsobservatory.org.uk/cgi-bin/srs_uk.cgi to see how times of sunrise &amp; sunset differ over UK.
Extension: Using session resource, provide chn with UK times of sunrise and sunset, how might these compare to Australia.
Use web links http://www.gaisma.com/en/dir/001-continent.html or http://www.sunrisesunset.com/ to find data for
Australia (use data for start of each month – 1st – to compare with UK data) - how do they compare month by month? Graph
both sets. Which is the month with shortest days (Aus)? What about UK? What explanations are there for these results?
Support: Use simple graphing software to create UK monthly graph. Print them out and ask chn to label them correctly
themselves.
Plenary:
Look at time zones across world (session resource). Place 3 small figures on globe at different points – which person would
have night first? Calculate times in each location given a starting time at GMT.
I can:
1. Understand that the Earth spins so different parts face the Sun at different times of the day.
2. Investigate the shadows created by the Sun’s light which change during the day.
2. Explain that the number of daylight hours changes during the year.
&copy; Original plan copyright Hamilton Trust, who give permission for it to be adapted as wished by individual users
We refer you to our warning, at the top of the You Will Need document, about links to other websites
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