Embedded Files
Igneous Rocks
Igneous rocks form when magma (molten rock within Earth) or lava (molten rock on Earth’s surface) cools and hardens
Igneous rocks can look very different depending on how fast or slow the magma or lava cools. When magma/lava cools slowly, it forms a coarse-grained rock forms. When magma/lava cools fast, it forms a fine-grained rock. When magma/lava cools very quickly, it forms shiny, glass-like rock.
Sometimes gas bubbles are trapped in the rock during the cooling process. This forms rocks with tiny holes. Pumice is an igneous rock that has many tiny air bubbles trapped in it.
We often consider two types of igneous rocks, depending on where the rocks formed:
Activity:
Use the instructions on the Crystal Size instruction sheet to carry out a simple investigation to demonstrate the effect of temperature on the size of the crystal formed.
Compare your samples with the examples of igneous rocks from the rocks sets.
Which sample of rock matches the closest to your investigation results?
Label your results, the types or rock and take a photo to go with your examples of sedimentary rocks.
Activity:
Look at the How to Make Crystals page on the ThoughtCo. website. Read through the different sets of instructions and decide which type of crystal you would like to try and make, (you may need to check which ones we can and cannot currently do).
Set up an iPad to timelapse the crystal growing and use an angle lamp to keep it illuminated 24/7.
- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
Activity:
Using the microscopes, look at the crystals we made last lesson in hot and cold conditions.
Use a phone or iPad to carefully take a photo of the different crystal sizes.
Look at the samples of igneous rocks in the rock kits, choose the ones whose crystal size matches those produced last lesson and take a photo.
In Google Slides or Google Drawings compare Extrusive and Intrusive crystal formation by including your photos and descriptions of the crystals, their size and how where and how they are formed, affects their size.
Activity:
Complete the 'Rock Cycle' summary including adding the labels to the arrows that connect each process.
Igneous rocks that form on Earth’s surface are called extrusive igneous rocks. These rocks form when lava cools quickly or very quickly.
Igneous rocks that form within Earth are called intrusive igneous rocks. These rock form when magma cools slowly.
Page updated
Report abuse