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The Earth and Beyond Adrian Wood
The Earth and Beyond
Why does this topic promise so much yet end up confusing so many?
Most of what we know about our planet in the solar system and the rest of space as been
accumulated through a steady trickle of sensationalized stories and accounts of the great
advances of humankind to put men on the moon etc. mixed with imaginative discoveries ranging
from the farcical to the preposterous that have left most people with a bizarre imbalance of
‘knowledge’.
Space and the promise of space discovery and travel have become one of the most powerful
political drivers and motivators that actually result in very little social change for the better that could
not have been achieved on other ways. Think of Kennedy’s speech about the man on the moon.
This created a huge technological driver for the US to use as a focus for development and yet the
programme actually achieved little practical result having spent enormous sums of money to give a
mere handful of people a ride of a lifetime.
The facts and figures of space are indeed stunningly awe inspiring and what we are discovering
about the galaxy through Keppler and Hubble presents us with incredible images of other worlds.
Unfortunately, so much is not science material that we can use to investigate in the classroom; nor
will it ever be if we take Einstein into account and accept that distances are simply too great and
therefore the times required to get to anywhere so prohibitive that the class visit to Alpha Centauri,
the closest star system at 4.5 light years, is definitely not a possibility.
So what are we left with? Actually, a great deal so long as we stick to the science and forget about
the little green men. The biggest problem is that we can’t see the Earth titling over. We can’t
actually see the Earth turning and change is so slow for us to understand easily that the orbit cycle
creates seasonal change.
Further afield, we can see images of Mars and Venus but knowledge about their atmospheres is
only knowledge and therefore academic. It might help to dress the facts up with a bit of imaginative
space travel and pretending that we are wearing suits that can cope with acids and freezing
conditions but we are still only dealing with abstract concepts that fall into the realm of ‘knowledge
that has to be learned’. This begs the question; what will we do with this knowledge? Also, when
are we ever going to use it?
Here are a few notes for consideration.
Aliens
Do people really think aliens wear rubber spiky masks and drive Dr. Who about? Are all aliens out
to conquer Earth? What are aliens? Where are aliens?
How to use the ideas around aliens….
Start with us -we are aliens to someone from another planet so let’s not ne precious about the
term. We have adapted to suit our environment, out gravity and the atmosphere. You can use the
same cause and effect to design logical inhabitants for other planets
Earth
Spaceship - what makes it precious and as far as we can tell - unique?
Classroom Investigations and practical ideas –
Rockets - shuttles - trajectory - gravity and escape velocity - atmosphere -mass/weight/density distance - making galaxies - eclipses - seasons - air/candles/oxygen-shiners and reflectors using push for travel etc.
Bias and what if rockets are not a girl thing?
It’s easy to get carried away with the whole space thing and forget that girls are often simply not
impressed. Think of that actual tasks you set and in particular, your grouping arrangements.
Learn about what there isn't - air, normal toilets, useful pull force
The Earth and Beyond Adrian Wood
Problem Solving
The salvation of understanding - be the man and then solve the problem and make the lunar
bicycle.
Getting information
Where from? The Geek Factor - overkill and useless - putting space into context? Websites,
books, geography, Google
Useful homework ideas
What goes into Or Who? How does Star Trek say anything? Can we use TV? Maybe we can make
a solar system the size of a credit card? Make a ‘space garden’ in a sealed lemonade bottle.
Design clothing to keep warm and cold etc. Design food containers suitable for zero gravity.
Learning Objectives for the Earth and Beyond
These are those from the National Curriculum
Learning Objectives - there are many more than this
S4/4/1a the Earth, sun and Moon are approximately spherical.
S4/4/1 b the position of the sun appears to change during the day.
S4/4/1c day and night are related to the spin of the Earth on its axis.
S4/4/1d the Earth orbits the Sun once each year.
S4/4/1 e the Sun and Earth are part of our solar system
Learning Outcomes
These are someone else's to start the debate - my comments in brackets.
The sun, moon and earth are spherical.
( wrong They are approximately spherical and the difference is very important)
The sun is a star and has planets orbiting it.
Our earth is one of those planets. The planets
vary in size and in the time they take to orbit the earth.
The only planet to sustain life is Earth.
(That we know of- there are currently – as of 12/10 = 515 exo-planets. Most of these are
huge and gaseous but there are over 200 that orbit in the recognisable habitable zone
around their star )
The moon is a satellite which orbits the earth.
The earth spins on its axis and so we get day and night.
The sun is the primary light source
(Wrong - it is one of millions of light sources but the closest one that gives us the most light –
it is our primary light source. The moon is a secondary light source which we should really
call a reflector. We might speak of moonlight but it’s really sunlight reflected onto the earth)
Shadows are formed when objects are in the sun's path.
Stars are grouped together in constellations. Our sun is a star but only appears so much
bigger to us as it is so much nearer than the others.
The Earth and Beyond Adrian Wood
Idiot Questions for Space include:
(These are taken from real lesson plans and other sources - notably, the Arkansas
Elementary Curriculum for Space and the Earth)
How many stars are there in the sky?
When was the earth made?
Could dinosaurs have lived on the Moon? (/ would have loved to find out.)
How do stars help us to predict the future?
Start of the Word List
Earth
Sun
stars
galaxies
planets
solar system
satellite
asteroids
meteors
orbit
gravity
Knowledge we need to know in order to develop the concepts required
History
Humans started to think that the Earth was flat, that all the stars danced about it in circles and
that as a consequence, all this happened to emphasize the importance of one silly animal –
humans. This belief developed and was promulgated by power systems around the world
who developed great mystical structures to control mere mortals, elevate the great and
glorious to deific levels and generally keep a very lop-sided balance of power.
It didn’t really matter that some people like Galileo, Copernicus et al presented evidence
suggesting we were living on one of a number of planets that went around the sun and that
even our sun was only one of millions. The systems were so powerful that these people could
be locked away and ridiculed.
Gradually, the evidence was too great and even though the power systems found bizarre
ways to explain their previous ignorance away of deny it altogether, they eventually had to
give in and accept what the telescope was telling them. Now we are left with the few who still
claim to believe the Earth is a flat disc but these tend to be small in mind and matter and of
little consequence.
The Earth
So now we know that the earth is a planet orbiting a small yellow star towards the end of an
arm of a spiral galaxy we adventurously call the Milky Way. We know that the planet tilts on
its axis and spins around once in what we call 24 hours. The orbit is 365.25 spins and thus
we have a year.
Seasons
The planet tilts over at about 23% as it goes around the star and this provides a neat way to
present first the northern hemisphere to the greatest light exposure and then the southern.
This means that when the north has the warmer season we call summer, the south as a
colder time called winter; and vice versa. It should be noted here that because there is much
less land mass closer to the southern pole than the north, there is less winter land to get
colder. This gives rise to a common misconception that we have winter in the north while they
never really get cold in Australia. Ask the Australians.
The Earth and Beyond Adrian Wood
Planets
It is helpful to consider the planets in two main groups. Inner and outer.
The inner are solid surface planets. Mercury is very close, small and ridiculously close to the
sun for any human use, Venus might have been once but the atmosphere is too reflective,
overheating the surface by trapping heat and contains all the acids you would not need for
any kind of life. Earth we know about so moving on, we have Mars that is most obviously
habitable were it not for the cold and that apparent lack of water although recent exploration
is changing our view on that, as it is on the Moon which I have not mentioned here much
because it is a satellite orbiting a planet even though it is not far off the size of Pluto which for
some inexplicable reason has recently been downgraded from planet to object. Were the
Plutonians advised of this?
The inner planets are also very small compared to the gas giants that form the outer list.
Ignoring the other planet which is assumed to have existed before being shattered into the
asteroid belt in the billiard ball movements of the past – read Velikovski- Worlds in Collision
Jupiter and Saturn can be described as failed star systems as they are enormous and have
multiple satellites, some of which look very interesting when it comes to life but not as we
know it – Jim
The rest, Neptune, Uranus, are also huge. Uranus rolls around the sun and one of them also
has great rings like Saturn but not so obviously visible.
There is so much available to discover about the planets and also so much art that refelect a
science view eg Hardy and Bonestall – book are available for lone on these topics.
Stars
These have a life cycle from birth to death when they seem to either collapse in on
themselves and then explode, or just explode. By all accounts, we are safe for a good while
because our own sun is fairly insignificant in its yellow stage and has a long time to go before
it does anything.
Its worth noting that the stars we see in the sky may not actually be there any more given that
the light from them has arrived into our eyes after millions of years travelling at 186,000 mps
– yes, that’s seconds. The star that the magicians are supposed to have followed, assuming
that that sort of thing is possible, is actually a recorded event of a super nova, observed in
Japan as well.
Stars also do not stay still as is commonly assumed. It is just that their movement relative to
any observable point on our planet is so slow that we cannot measure it. What is now known
is that planets orbit stars, star systems themselves move through space with the magnetic
pull of the whole galaxy rather like the cream going around on the surface of the coffee and
that there are countless galaxies all doing the same thing. By the time we get here, we have
lost anything of tangible use to the primary classroom. You either find it interesting or a
dreadful waste of thought.
Distance
Distance is ridiculous and I really cannot find a way to explain this to children. You can scale
everything down to centimeters and start a line in the corner of the field to say that if I were
the sun and James was Mercury, he would be standing here and if John were Venus he
would be here…… but what happens to poor Eric who is Pluto? No matter how you try to
scale things, Eric has really got to get off down the road a few miles to make this anything like
sensible.
All this says that telescopes are time machines and that the Hubble as collected images from
very distant regions with light that would otherwise be taking millions of more years to reach
us. What it sees will probably be very different to what we might see. It has been said that if
an Alpha Centaurian living on a planet where to look at Earth through a telescope, he would
see dinosaurs.
Time
Einstein has a take on this which I will not expand upon here but generally, we can say that
time is relative to distance and that we can never travel faster than light. In terms of space
travel, it’s a bit like travelling across the ocean on a biscuit.
The Earth and Beyond Adrian Wood
Reading references
Apart from the thousands of good books available, I would recommend in particular Clarke
and Asimov. Together with Larry Niven, they have good stories to fire the imagination based
upon real science
Eclipses
There are two types:
Lunar when the Earth is between the Moon and the Sun
Solar when the Moon is between the Sun and the Earth
Anything less than a full eclipse is called a partial and this event is easy to model with a torch
and two balls. For information about creating a test solar system for the classroom, read
separately.
Weather
Weather study could form a part of this project or better still a separate study which is why it
is not included here other than to point out the value of collecting newspaper weather
summaries during the year to use as evidence for temperature change and as a starting point
for making comparisons with known weather on other planets.
Misconceptions
There is a paper on a separate screen called Misconceptions in Primary Science. This paper
would form a useful reference example for the research task. I refer to it here because there
are a few misconceptions relating to space and the Earth.
Below are a few more.
Astronomy or Astrology
Which is which and what do they mean?
The Earth is not a finished deal
Everything is still changing. Maybe the tectonic plate movements have slowed down as the
core has cooled over the last 4.5 billion years ago, but they are still moving and we still
having the volcanic eruptions and tsunamis etc. Bigger changes like mountain building are a
lot slower but they are still happening.
The Sun
The sun provides all energy for the Earth to function. Sun rays will kill you but they don’t
because of the atmosphere which screens out the harmful rays.
Shooting Stars
These are not stars but often very small particles of meteorites that burn up with friction in the
atmosphere as they are pulled to the Earth. They travel at phenomenal speed and for a
fraction of a second can be seen on clear nights. Some are from the known showers
Star Wars
Just because this has all been around for 30 years and parents and grandparents can quote
characters and events, it does not make it real. Sadly, there is no Tatooine and Yoga etc. and
by the same token, there is also no Death Star about to blow us to smithereens and therein
lies some of many misconceptions children end up believing. There is no sound in space
because there no atmosphere to transmit the sound. Also, despite the beautiful shapes of the
various craft, there is no need for spaceships to be streamlined. Shape doesn’t matter
because there is nothing there to slow them down.
Astronauts and Mass
Children sometimes think that astronauts are weightless in space. Actually, they are but only
because there is gravity pull from a planet to make them so. Mass and weight are different
things. A man mass will be the same anywhere but his weight won’t. Mass is the amount of
stuff he is made of but if he has a large mass, he will affected my greater gravity pull when he
gets to Earth. Kilograms are a mass measurement. The man would still be the same 90 kilos
on the moon but he will be 6 times lighter because the moon gravity is 6 times less than
earth.
The Earth and Beyond Adrian Wood
Safety First
This is perhaps the most important message to pass across to any would be astronomer.
Never look directly at the sun
Always talk about looking at night stars: even the moon can cause eye strain and temporary
blindness when looking through binoculars or a telescope.
Telescopes
These are time machines because they capture light long before you see it with the naked
eye. They are also expensive and difficult to use because they invert the image, need a very
steady hand and actually tell you nothing you can’t discover in a good book. Try large
binoculars on a tripod because they let in more light and have a wider field of view so
although you won’t see back to the Big Bang, you will see a fantastic display not otherwise
visible.
Telescopes are a useful investigation study but during the school day only so any real
observations have to be made privately after school.