Australia Lesson Activities - Science

THEME: Limestone Gorge
SUBJECT AREA: Science
TOPIC: Rillenkarren

Following the advice on the National Parks Commission sign, we visited the Calcite flow at sunrise, to watch the morning light sparkle on the cascades. This white formation appears in the steep dry creek bed as a rushing waterfall, frozen in time. The turbulence of the fast flow of calcium-rich waters down this slope forced carbon dioxide (the same gas which animals convert the air they breathe into) out of the water. This chemical reaction results in the release of solid calcium carbonate (called calcite) from the water.

Over time, layer upon layer of calcite sediment builds up around solid objects – in this case, tree roots and rock. Eventually we are left with the striking white cascades we saw at Limestone Gorge, which could easily fool an uninitiated onlooker to think that water was flowing there.

Each wet season, the calcite cascades trap minute algae and other small organisms, causing them to change colour until they die in the dry season, leaving the white calcite exposed.

“This site holds particular significance for the local Ngariman Aboriginal people. It forms a part of their Flying Fox dreaming, which extends across many of the watercourses and natural features of this area. Traditionally the white calcite (Kulge) was used to make body paint for ceremonial purposes which were held in the vicinity of the present Limestone Gorge camping area.”

Near the Calcite flow, we saw a rock formation that had baffled us 65 days ago, in the Chillagoe caves, where another limestone founded land system exists. The exposed limestone surface resembles tiny choppy waves on a lake, with hundreds of sharp peaks, and, we finally discovered, is known as Rillenkarren. In Chillagoe, there had been no interpretive signs to tell us about it, and while the intrigue had been captivating, it was great to see it again, and to understand just how it was formed.

Rillenkarren is created by acidic rain - a very different type to that which cities may get from pollution. It is actually just a weak carbonic solution that is formed in the clouds. The carbonic solution dissolves the softer limestone rock causing a jagged, rippled effect. Dolomite, the type of limestone found throughout the park, is subject to rapid corrosion from many sources.

See Crister’s Geography update for info on some other neat geological phenomenon found in the Karst landscape.

The aboriginal people found a process that made splitting the rillenkarren easy. A chunk of rock is heated in a fire then cooled very quickly by dipping the stone into a creek. This gives the remaining rock splinters rather sharp edges, useful for crafting spearheads, knife-edges and axe heads.

Suggested learning activities:
Research the element Calcium. How much is there in the earth’s crust? Where is it found? What are its commercial uses? What purpose does it serve in our bodies? Find out all the practical information you can on this mineral.
Explore the commercial uses of Limestone. Many uses have been found for the stone in places where it is abundant around the world, just as the aborigines did. In the United States, it has been used for building fence posts, houses, flooring etcetera. What uses can you think of? What other types of limestone are there apart from Dolomite?

Feed your children wheat Joshua and bel

THEME: Creepy Crawlies
SUBJECT AREA: Science
TOPIC: SPIDERS!

This morning, while I was packing up my swag, or sleeping gear, I heard a shriek from Mike’s tent. Jason and I went over to see what was up, and Mike told us that a spider had just fallen out of his sock while he was putting on his shoes. It was a Tarantula spider about the size of the palm of one’s hand. The story, being told to the rest of the group, was of a 10-pound spider the size of a small dog! Could you imagine a spider that size?!

Here are some neat factoids about spiders:

- All have eight legs.

- Insects have six legs. That is one way to differentiate a spider from an insect.

- Some spiders here in Australia can become as big as a mouse! (And as hairy!)

- Most spiders feed on solely on ants. There are more than 200 species of ants in Australia!

- Spiders forage for their food mostly at night. Some hide in their borrows waiting for prey to come along.

- All spiders are carnivorous, meaning they only eat meat.

- Sheet flooding, where water flows like a sheet over the desert is the greatest hazard to spiders living in their burrows. Many spiders build trapdoors similar to a plug used in your bathtub to keep the water out.

- Many spiders’ venoms are poisonous, so you should be very careful and aware of them!

Every morning before I get up I check my shoes and see if any ‘little dude’ has made a home in them! I’ve been fortunate to see a few, but none as big as Mike’s this morning!

*By Crister

Suggested Activities:
-Can you find any other neat info about spiders?
-Just like snakes, spiders are usually killed when discovered by humans. Can you think of the reasons why this happens?
-Find a spider’s web and make a list of any prey caught.

THEME: Birds
SUBJECT AREA: Science
TOPIC: Order Psittaciformes

2001 October 17, Wednesday.

Parrots belong to the faunal Order (or family) of Psittaciformes. Their bright colours easily distinguish them, along with their short hooked beak, and feet with two toes directed forwards and two directed toward the rear.

Parrots are unique in the way that they are the only bird (other than ‘Big Bird’ from Sesame Street) that can use their feet like we use our hands; they pull apart their food and feed themselves using their claws, which they manicure painstakingly. All parrots use their beaks for climbing.

Parrots are herbivores, feeding primarily on seed and fruit. They are also monogamous, staying with a single mate for their entire lifetimes, and, apart from the few which migrate in search of food, (nectar feeders) they tend to be sedentary, that is, to stay in a single area all their lives, and use the same nesting place each breeding season. In the wild, a parrot will live for over one hundred years. The size may vary ranging from the Goliath cockatoo (60cm) to the Budgerigar (12cm).

The two sub-families that are seen often are the Cockatoos (Cacatuidae), Lorikeets and Typical Parrots (Psittacidae). Parrots are the most intelligent species of bird, in the way that they have the largest memory for detail; and this causes each individual bird to develop a complex and very distinguishing personality.

Every type of parrot has its own distinctive characteristics. They also learn to speak, and imitate other sounds from their external environment. This is done by pet birds in a simple attempt to communicate with their owner, who forms an emotional substitute for their mate in the wild.

Most Parrot species mature at around twelve months of age. They nest in tree hollows and termite mounds, and for this reason their eggs are white. Birds who use an open nest in a tree or on the ground develop colour and speckles in their eggs, to protect them by camouflage from animals such as reptiles who might find them a tasty meal.

Parrots, like other species of birds, have a single oil gland at the base of their tails, in place of the ones we have all over our bodies, to lubricate our skin. The oil is collected from this gland in the beak, and spread across the feathers, one by one, to protect them. This is called preening.

Suggested learning activities: Find an animal whose life expectancy is over one hundred years. Find out what they feed on. Are they herbivores or carnivores? How large is the animal?

feed your children wheat
joshua and bel