Teaching ScienceIdeas and help for trainee Science teachers

Another one of your questions was about Day, Night and Seasons. I’ll try and link to some good animations and guides about this that are already on the web.

The Earth is always lit from one side by the Sun. The side that is in shadow is in Nighttime, the side that is lit by the Sun is in Daytime. If you follow one spot on the Earth such as London, as the Earth spins it will eventually move from night into day and then later back into night time again. From where we are standing it looks like it is the Sun that’s moving instead.

You can see what the view from space above London is like right now with this viewer.

You can see what’s happening on this animation

http://www.childrensuniversity.manchester.ac.uk/interactives/science/earthandbeyond/dayandnight.asp

To add to the confusion: The Earth is slightly tilted on its axis. This means at some times of the year, the Northern Hemisphere is tilted slightly towards the Sun (Summer) and at other times of the year it is tilted away from the Sun (Winter). At the Spring and Autumn Equinox the two hemispheres are neither tilted away or towards the sun.

There are some more diagrams on this page which illustrate this.

Here’s a nice animation of the Earth going around the Sun, showing the effect of the tilt on the seasons.

http://mesoscale.agron.iastate.edu/agron206/animations/01_EarthSun.html

The tilt also affects the length of a day on Earth. You can explore that with this animation

http://www.childrensuniversity.manchester.ac.uk/interactives/science/earthandbeyond/sunrisesunset.asp

In the winter the Sun rises later and sets earlier. We have short days and long nights. In the Summer the sun rises earlier and sets later, we have long days and shorter nights. At the Spring and Autumn equinox the length of day and night is equal (equi = equal nox=night)

More Info

http://www.bbc.co.uk/science/space/solarsystem/earth/solsticescience.shtml

http://www.boutichesaid.cv.dz/Earth/EarthLight/EarthLight.htm

http://en.wikipedia.org/wiki/Seasons

http://www.badastronomy.com/bad/misc/seasons.html

http://www.fourmilab.ch/earthview/vplanet.html

http://www.bbc.co.uk/schools/ks2bitesize/science/revision_bites/earth_sun_moon.shtml