Basic Skills for Earth Sciences

by

Arlëne Hunter, Dee Edwards and Dave Williams, The Open University

This courseware module covers some of the fundamental principles of maths, chemistry and physics needed to study first year geology at university level. It enables students to revise the specific topics they need and so increase their confidence to cope with these topics in their coursework. The module is subdivided into three main areas: maths, chemistry and physics. Within each subdivision the ideas presented use geological examples. In this way students are introduced to some of the science in geology and the hope is that this will make the module both interesting and relevant to their coursework.

This courseware module occupies about 20Mb is divided into four sections. Students are directed to section 4 first - How to use this module. In sections 1-3 there are pre- and post-assessment tests. Each test comprises ten questions covering most of the subjects dealt with in the section. One attempt at each question is allowed and at the end all the results are listed. From the pre-assessment test students can discover which topics they need to revise, and from the post-assestment tests how well they have understood the material. The four sections are shown on the menu page illustrated below

1. Calculating the size and shape of the Earth

Many of the points in this section are dealt with by means of worked and set examples. Manipulating numbers: adding, subtracting, multiplying and dividing fractions and powers of ten; significant figures. Calculating areas: squares, rectangles, circles, ellipses and triangles. The square root; calculating the circumference and perimeter of circles and ellipses. Calculating volumes: cubes, spheres, cylinders and prism/cone. Using trigonometry: angles and the trigonometric functions sine, cosine and tangent; usage in the Earth and the science of surveying. Graphs in geology: gradients and graphs. Intercepts and the equation of a straight line. Linear, log-linear, log-log and triangular graphs; other ways of illustrating relationships in geology. Density: why different rocks and objects weigh different amounts and how density is measured.

Most examples have a geological basis. Here, density is explained using rocks and fossils

2. What is the Earth composed of?

Atomic structure: the definition of a rock, through minerals, compounds, elements and finally the atom. Building blocks in geology: how and why compounds form, how to write and balance chemical equations. The building blocks: the silicates, and non-silicates. The Si-O tetrad, single and double chains, sheets and 3D structures, and how they link with the main mineral groups. Oxidation and reduction: Oxidation and reduction. The importance of such reactions in geology. Isotopes: Radiogenic and stable isotopes, half lives and the use of isotopes for dating rocks and in petrogenetic problems. Chemical cycles: Links chemistry and the natural environment using the hydrological, carbon, nitrogen and rock cycles as examples.

This illustration shows how materials may be broken down systematically, arriving finally at the atom

3. Earth physics

Calculating force, mass and velocity: the concepts of speed, velocity and acceleration, and their relationship to force. Newton's First and Second Laws of Motion. Energy waves: introduces diffraction, refraction and reflection. The importance of the properties of energy waves in geology. Gravity: Newton's Third Law of Motion and Law of Gravitation; the difference between mass and weight. What are earthquakes? the geological processes that lead to earthquakes and their global distribution. Introduction to the types of energy wave involved and the ways in which they can be recorded. The Mercalli and Richter scales. Magnetism: the principles behind the Earth's magnetic field, including true and magnetic north, and the variation in position of magnetic north with time. Palaeomagnetism and the concept of Curie point for minerals. Seismic waves: focuses on the refraction and velocity of body waves. The concepts of stress and strain in relation to seismic wave velocity.

Information is given in a number of ways. In this interaction the student is aksed to label a diagram illustrating the nitrogen cycle

Running the software

The different parts of the module are accessed via a main menu and navigation around the module is by means of buttons along the base of the screen.

Part of animated sequence illustrating Gallileo's famous cannonball experiment

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