Fred Moore/flickr, CC BY-NC
Curious Children is a collection for kids. When you’ve got a query you’d like an knowledgeable to reply, ship it to firstname.lastname@example.org You may also just like the podcast Think about This, a co-production between ABC KIDS hear and The Dialog, primarily based on Curious Children.
The place do rocks come from? – Claire, age 5, Perth, WA.
Wow, Claire, what an excellent query. Sitting in a college, I hardly ever get requested such good questions. So, thanks.
As unusual because it sounds, rocks are comprised of stardust; mud blasted out and comprised of exploding stars.
In reality, our nook of area has many rocks floating round in it. From actually superb mud, to pebbles, boulders and house-sized rocks that may dissipate within the night time sky to make meteors or “capturing stars”.
The Moon and our native planets – Mars, Venus and Mercury – are simply the biggest rocks floating round our a part of area. These are all comprised of area mud caught collectively over billions of years.
Curious Children: how was the Earth made?
NASA/JPL-Caltech, CC BY
The ‘mild’ rocks are on the Earth’s floor
Planet Earth is a rock too, however a lot has occurred because it was shaped from mud and small rocks that smashed and caught collectively 4.543 billion years in the past.
Because the area mud hit one another to make the earth, it acquired tremendous scorching and melted. The Earth was, at the moment, a spinning ball of red-hot lava flying by way of area.
On this melted lava planet, heavy bits of the earth sank and the sunshine frothy bits gathered on the floor.
Have you ever ever seemed intently at a glass of milky espresso at a restaurant? The darkish heavy espresso is on the backside, whereas the sunshine, frothy milk sits on the highest. Properly, our planet was a bit like that espresso billions of years in the past.
We don’t see the actually heavy rocks lately as a result of they sank deep within the planet very early on. The rocks we see on the floor are just like the frothy milk! They have been mild and rose to the highest. Then, as time moved on, the planet cooled and froze to develop into the stable earth we’ve got now.
I do know most rocks are heavy. However actually some rocks – even actually large ones like Uluru – are literally a lot lighter than the rocks discovered within the deep Earth.
Lava and plates
These rocks on the Earth’s floor truly transfer round. Massive chunks the scale of continents (known as “plates”) jostle one another and this will trigger earthquakes. A few of them get compelled underneath different plates and warmth up and finally soften. This kinds extra lava. The lava erupts from volcanoes, then cools and kinds new rocks.
Listed below are some photos of lava within the melted state after which after it has cooled down:
Petr Meissner/flickr, CC BY
Curious Children: how do mountains kind?
Mountains and gems are additionally rocks
Mountains kind the place two plates smash into one another. The rocks that get caught between two of the Earth’s plates get squashed underneath large pressures and warmth up. These can kind actually lovely rocks. Typically gems kind in these rocks and folks attempt to discover them to make jewelry.
Rain and ice break up the rocks in mountains. These kind sand and dust that get washed out to kind seashores, rivers and swamps. This sand and dust can get buried, squashed and heated, which finally turns them into rocks.
Rocks include a file of the historical past of our planet; what’s has been by way of and what’s able to. We’re solely simply studying find out how to learn it.
So, subsequent time you see a rock, simply suppose what an unimaginable story it accommodates.
Hiya, curious youngsters! Have you ever acquired a query you’d like an knowledgeable to reply? Ask an grownup to ship your query to email@example.com
Please inform us your identify, age and which metropolis you reside in. We received’t have the ability to reply each query however we’ll do our greatest.
Alan Collins receives funding from various business and authorities sources together with the Australian Analysis Council