C3 01 Lesson Plan Continued

OCR 21st Century Science: C3 Chemicals in our lives – risks and benefits c3_01 Moving continents

Resources

Student Book pages 172−173 . Interactive Book: Naked Scientist ‘What are tectonic plates?’ . Interactive Book: News Clip ‘Danger! An earthquake in the UK’ . Homework pack c3_01 Files on Teacher Pack CD: c3_01_worksheet Rock samples (preferably a basalt and a sandstone) or pictures; dropper; compass

Learning outcomes C3.1.1 understand that geologists explain most of the past history of the surface of the Earth in terms of processes than can be observed today C3.1.2 understand that movements of tectonic plates meant that the parts of ancient continents that now make up Britain have moved over the surface of the Earth C3.1.3 understand how geologists use magnetic clues in rocks to track the very slow movement of the continents over the surface of the Earth C3.1.4 understand that the movements of continents meant that different rocks in Britain formed in different climat es Ideas about Science IaS 3.3 a scientific explanation should account for most (ideally all) of the data already known. It may explain a ran ge of phenomena not previously thought to be linked. It should also enable predictions to be made about new situat ions or examples

Literacy focus: Describing observations and writing explanations. Numeracy focus: Developing a sense of scale of geological time. ICT focus: Accessing pictures/animations of rock processes/maps of continents. In this lesson students are learning to: . explain that rocks formed by processes that are still happening today . explain the evidence that land making up Britain has moved across the Earth . understand that scientific theories account for observations, make links and predictions Key vocabulary tectonic plates . supercontinent . plate tectonics . igneous rocks

Obstacles to learning This lesson assumes that students have already met the theories of continental drift and plate tectonics, covered in Physics module P1 (lessons p1_08 and 09, Student Book pp.220−224). If students have not completed module P1 and have not studied these ideas elsewhere, it may be necessary to outline the essential points. Note that this lesson requires that students consider earlier plate movements than those considered in P1. Also, in P1 the ideas about magnetisation of rocks are for Higher tier only but in this module they are required for all. The vast timescale of geological changes is a very difficult idea to grasp and changes to the planet Earth can appe ar complicated and confusing.

Stimuli and starter suggestions . Give students samples or pictures of rocks to study including an igneous rock and also a sedimentary rock containing a fossil. Ask students to describe the rocks and make a list of what the samples could tell them about the rocks and the location where they were found. Students may note colour and texture, porosity, strong/brittle, hard/soft, if it is uniform or made up of different materials, the shapes of the fossils. Geologists can identify the type of rock, the chemical composition of the rock, how it was formed, and its age (from the fossils and other methods).

Learning activities worksheet c3_01 Low demand . Ask students what signs there are today of changes taking place on the surface of the Earth – volc anoes, earthquakes (show pictures of recent examples), measurements of sea-floor spreading, parts of the rock cy cle (erosion by ice, water and wind; transport and deposition). Note those that are caused by tectonic activity and lo ok at examples of the changes produced – e.g. new igneous rocks, metamorphic rocks, uplift and tilting of rocks. E xplain that all the changes we see happening today are also found in old rocks, specifically rocks found in Britain. S

COLLINS NEW GCSE SCIENCE © HarperCollinsPublishers Ltd 2011 c3_01 Lesson plan continued how samples or pictures of different rocks found in Britain – e.g. recent (geologically) basalts on the west coast of S cotland, older igneous rocks and slate in Wales, pre-Cambrian sedimentary rocks in England (Leicestershire, Char nwood Forest), chalks and sandstone. Students should make a record of the processes that take place and the typ es of rocks found as a result. The worksheet provides more tasks.

Teaching and learning notes: Use the starter to assess students’ prior knowledge of plate tectonics and the rock cycle. Students may need help in seeing that what is happening today is evidence of processes that happened in t he past. Use the analogy that seeing someone throw a crisp packet in a rubbish bin which is then collected and tak en to a landfill site provides an explanation of why we find crisp packets in old rubbish tips.

Standard demand . Explain that tectonic plates have been moving for thousands of millions of years and have for med a supercontinent several times. Note that Scotland and the rest of Britain were once parts of different continen ts that have moved from the Antarctic, through the tropics and forming Pangaea about 200 mya. Further changes h appened when Pangaea began to break up (60 mya) and a part of Scotland was torn off to become part of Newfou ndland in N. America. All this time new rocks were being formed on top of one another, and then exposed by uplift and erosion. Use pictures, animations and maps (such as Student Book p. 173) to describe and explain this story a nd cover the specification points. Students may then retell the story in their own way – perhaps writing a story, dra wing a series of cartoons, presenting a drama or dance sequence.

Teaching and learning notes: Students need to appreciate that different parts of Britain were in different locations, have moved through different climates during which various types of rock formed and evidence for this.

High demand . The clues provided by magnetisation of rocks requires a high level of understanding but is not excl usively Higher tier. Explain that rocks contain magnetic material. When rocks are molten, the magnetic field lines u p with the Earth’s magnetic field – i.e. they point north–south. Demonstrate this with a compass (or a magnetised pi n floating on water). When the rocks solidify, this alignment becomes fixed, but as the rocks move the alignment ch anges. Rocks formed at different times have different magnetic alignments (note that this is complicated by the reg ular precession of magnetic north and the irregular flips of the North and South poles). Geologists can use the mag netic alignment of rocks to match up rocks formed at the same time and in the same location, and to work out wher e the rocks were when they formed. Students could do research on this topic and report to other members of the gr oup. There is support on the worksheet.

Plenary suggestions Prepare a summary of what we know about the rocks of Britain. Students offer points to build up a complete list .

Student Book answers Q1 They see changes in rocks caused by tectonic activity today; they see similar evidence in British rocks formed a long time ago; so they think that these were caused by tectonic activity. Q2 a) There are different types of rock in Britain formed under different climate conditions. b) Rocks contain fossils of animals and plants found in tropical climates. Q3 There are different fossils on either side of the boundary. Q4 The direction of the magnetism becomes fixed in the rock as it solidifies; as the rock is carried over the Earth its direction is altered. Q5 Similar rocks, fossils, magnetic orientation in both locations. Worksheet answers Activity 1 (Low demand) Q2 Statements referring to weathering and erosion go in the second column, all the rest into the first. Q3 Rocks of different types will have been formed in different places or at different times Activity 2 (Standard demand) Q1 a) Stories based on the sequence of plate movements shown in the maps. b) Plate boundaries; igneous rocks; faults and re-alignment of rocks caused by earthquakes; metamorphic rocks formed by heat and pressure; fossils of organisms living in different climates; (magnetic alignment). Q2 The positions on the timeline should be something like this: 500mya.A...... 400mya...... 300mya...... C...... 200mya...D...... 100mya..E...... B..present Activity 3 (High demand) Q1 Magnetism fixed when rocks cool; alignment changed when continents moved; evidence of where and when rock was formed. Q2 The rocks formed in different places; moved together or at different times; magnetic North has moved.