The surface of the Earth is constantly changing. Continents have collided and drifted apart, and new oceans have formed (over millions of years) to give us the Earth we have today. But the Earth is still changing and some surprising things are happening right now.

The Earth's changing surface

The student activity is a simple way to show plate tectonics in action at a very significant, unique area of our planet and how this has shaped and continues to shape the Earth. Before the students do the activity it is helpful to give them some background on what is happening in the Afar region and look at plate tectonics. Students should be encouraged to take notes as this will help with answering some of the questions on the student worksheet. The websites below may also be helpful with background information.

Materials required

These websites give more detailed information on plate tectonics and other areas of earth science www.gcsescience.com/pwav56.htm, www.rsc.org/education/teachers/learnnet/jesei/index2.htm, www.see.leeds.ac.uk/structure/dynamicearth/index.htm, http://science.discovery.com/videos/100-greatest-discoveries-shorts-the-mid-atlantic-ridge.html, http://see.leeds.ac.uk/afar

Timing: around 30 minutes (could be longer with discussion)

Answers

Most of the answers will be generated by the students themselves, but for question 4 there is a misfit because we cannot draw the coastlines exactly and because erosion, deposition and volcanoes can change the coastlines over time.

Curriculum links


Environment, Earth and universe

Environment, Earth and universe 8b: The surface and atmosphere of the Earth have changed since the Earth's origin and are changing at present.

Applicable examination units

Exam Board Units

AQA: GCSE Science

C1b The Changes in the Earth and its Atmosphere

OCR Gateway Science Suite: GCSE Science

C2 Rocks and Metals

Earthquakes and volcanoes

OCR 21st Century Science Suite: GCSE Applied Science (Double Award)

Unit 2 Science for the Needs of Society

Earth and the universe

WJEC: GCSE Science

 

C2 Earth Science

Geological processes

Northern Ireland Curriculum: GCSE Single Award Science

 

Module: 3 Chemical patterns and our environment

3.11      (i) Explore plate tectonics theory.

(ii) Recognise that volcanoes and mountain building are likely to occur at the edges of tectonic plates.

(iii) Recall that earthquakes occur when tectonic plates move last each other.

3.12 Recognise that the surface of the Earth is constantly changing.

 

Science for you to try

The Earth's changing surface

The surface of the Earth made up of different plates which move at a very slow rate, but how far will they travel in 15 million years time? Try this activity and fast forward time to find out!

Africas new ocean Map

Procedure

Download a pdf of the instructions here.

You will need:

1. On your printed map mark the outlines of the coasts and other significant topographic features such as mountain ranges. Mark on the plate boundaries in a different colour.

2. Either cut along the plate boundaries, or perhaps better, use tracing paper to draw outlines and then cut out the tracings and slide back until they fit snugly next to each other. This is what the Afar region looked like 15 million years ago. Note: It is best to stick the Nubian plate tracing to the original map first, and slide the Arabian and Somalian plates.

3. Once you have done this, mark matched points along the plate boundaries. See the PowerPoint presentation for more details.

4. Slide the plates back to their original positions so that you get a gap between the plates.

5. Now draw lines between the matched points on the different plates. See PowerPoint presentation for a diagram. This gives you a measure of the amount of opening that has occurred. If you print out the pdf map on A4, then 1 cm is 150 km. Alternatively, 10 degrees on the figure is approximately 1100 km.

6. To work out the future position of the plates (where they will be in 15 million years time), move the plates away from each other twice as far again. To do this, double the length of the lines and mark these on your map, however you should only to do this for two of the sets of lines - Nubia-Arabia and Nubia-Somalia.

7. Move the tracings of the Arabian and Somalian plates to their new positions in 15 million years time. To check that it has worked, measure the distances between the match points separating the Arabian and Somalian plates and check that they have doubled in length.

 

What's next?

Now that you've gone forward in time, what does the region of Afar look like?

1. Which plates have moved furthest apart?
Arabian - Nubian
Arabian - Somalian
Nubian - Somalian

2. Take the longest distance between your match points, how far have these plates moved in kilometres? (1 cm = 150 km)

3. This movement has taken 15 million years. How many kilometres do the plates move in one million years?

4. When you placed the plates directly next to each other (how they were 15 million years ago) the plates didn't fit together perfectly. Why do you think this is?