This week we're thinking about the rocks which have formed Oxford: what type of rocks they are, where they came from, and the the different architecture they were used to build.
A few weeks ago I visited Headington Quarry to see where the limestone for many of Oxford's buildings came from. You can learn a little more about the quarries and buildings in this video I made. There's a Maths challenge we'll attempt at the end of the week.
Today, you can explore your own Oxford rocks, in your own garden. It might be that you have some limestone or sandstone in your garden, but how do you know? Gather a few different types of rocks from your garden, and use this chart to help you discover what type of rock they might be:
As well as the rocks you can find in your garden, there is also soil, which is largely made up of rocks which have been 'weathered' (broken up) over time. Depending on where you live, the soil contains different amounts of sand, clay, silt and rotted plant material.
You can do this experiment from the Royal Horticultural Society to find out whether your soil is sandy, clay, silt or loam.
If you have more time, you can find out exactly how much of your soil is made up of sand, clay, silt and rotted plant material using this method:
1. Take a jam jar or an old drink bottle and filling a third of it with soil.
2. Fill the jar/ bottle almost to the top with clear water.
3. Stir the jar and let the soil settle for an hour.
4. When you come back, you can observe and measure the different layers in the jar. Because sand particles are the biggest and heaviest, the layer at the bottom will be sand. Above that layer, you will find a layer of silt, then clay, and then plant material will be floating at the top of the water.
5. To calculate the percentage of sand/ silt/ clay in the soil, divide the depth of each layer by the total soil depth in the jar, and multiply by 100.
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