1. Studying igneous rocks Catastrophe Etna 3 RockSS1 The description test Look at and feel the rock and come up with some words to describe it. The observation test Look at the rock through a magnifying glass. Is it made up of crystals or grains (like grains of sand), or does it have no grains or crystals? The crystal size test If the rock has crystals, how big are they? Give a rating of 1–5, with 1 being very tiny crystals and 5 being very large crystals. The hardness test Try to break the rock with your hands. If it breaks easily it is very soft. Give a rating of 1–5, with 1 being very soft and 5 being very hard. The water test a Put the rock in a tub of water. Does it sink or float? If it sinks it is denser than water. If it floats it is less dense than water. The cake layer test Is the rock arranged in layers like the sponge, jam and icing in a sponge cake, or does it look the same all the way through like a fruit cake? b Does the rock soak up the water? If it does, it is porous. If it doesn’t, it is non-porous. Activity from the Catastrophe unit © upd8 wikid, built by cracking science This page may have been changed from the original

2. Igneous rocks – which would make the best lava barrier? Catastrophe Etna 3 RockSS2 Name of rock Description test Observa- tion test (grains, crystals or neither) Crystal size test (1–5) Hard- ness test (1–5) Water test A (denser or less dense than water) Water test B (porous or non- porous) Cake layer test (layers or no layers) Report for Antonio – which rock type would make the best lava barrier, and why? Activity from the Catastrophe unit © upd8 wikid, built by cracking science This page may have been changed from the original

3. Salol investigation Catastrophe Etna 3 RockSS3 1 Put on eye protection. Fill a beaker with warm water. Put two slides in the water along with a test tube containing two small spatulas of salol crystals. 2 Place two cold slides on a piece of coloured paper. (The slides have been in the freezer.) 3 The salol should have melted by now. Half fill a squeezy pipette with the liquid. 4 Place a few drops of salol onto the middle of one of the cold slides. 5 Quickly, place the other cold slide on top. Press down gently. 6 The salol will cool very quickly on the cold slides. Watch what happens. 7 Remove the slides from the beaker. They will be warm. Place them side by side on the bench mat. 8 Repeat the method from step 3 onwards. Will the salol cool more slowly or quickly on the warm slides? What difference does this make to the appearance of the salol in step 6? Activity from the Catastrophe unit © upd8 wikid, built by cracking science This page may have been changed from the original

4. Catastrophe Etna 3 RockSS4 Igneous rock summary a are formed from hot liquid rock. This means they… b are formed when hot liquid rock cools down. This means they… c can be formed when liquid rock cools down quickly. This means they… d can be formed when liquid rock cools down slowly. This means they… e have crystals that are strongly joined together. This means they… f have interlocking crystals (the crystals are touching with no gaps). This means they… A are hard. B contain crystals. C never contain fossils (fossils are the remains of plants or animals that have got preserved in rock). D are non-porous. E have large crystals. F do not have layers. G have small crystals. Igneous rock summary On the opposite page is a list of facts. Use the endings below to finish off each fact. One fact has two different endings. These facts apply to most – but not all – igneous rocks. Most igneous rocks… Activity from the Catastrophe unit © upd8 wikid, built by cracking science This page may have been changed from the original