Dance of the Seasons

I’ll let you watch some of the nonsense we’ve been doing in Grade 6 Science class before providing commentary.

Please do not judge us!

And now for an explanation…

We are learning about the seasons.  Besides being something that the Province requires us to teach (and grade 6s to learn), it’s the source of many misconceptions. But when asked what truly causes the seasons, the one word that should come to mind is this… TILT.

And so to demonstrate this idea, I came up with something of a seasonal dance, wherein as we tilt at the waist and rotate counterclockwise, we can mimmick the various inclinations of Terra as she revolves around Sol.

If this is confusing to you, please ask your grade 6 student for a better explanation.

The North is our head,  the South is our, um… tailbone.  And as we revolve around Sol, our two hemispheres present themselves more directly to the rays of Sol, and so experience preferential warming (or cooling) known as summer (or winter).

As I say, ask the kids about it.

Equal Night

Last night, at precisely 11:48 am, a very special thing happened: the Sun crossed Earth’s equator. This is what it looks like, courtesy of Astronomy Picture of the Day:

Now that explanation might not make a whole lot of sense. To understand it, you need to know a few things. Or be reminded of them.

First of all, recall that Earth spins. It spins about an imaginary pole (well, two of them if you include the north and south poles), the official term for which is axis. When that axis is directly up an down (vertical) with respect to our orbit around the Sun, the the Sun shines down directly on the equator.

(Here’s an animation that illustrates what we’re talking about here.)

And that’s what happened last night. The vernal equinox. Equal nights.

The upshot of all this is that spring has sprung. From here on in, the days become longer and the nights shorter. In 91 days we’ll have the longest day (and shortest night) and the days will begin to get shorter again.

Happy spring!

Additional Resources

An explanation of Earth’s Rotation (Wikipedia).
Motion of the Earth (from the Office of Naval Research).