Earth Science – study of the Earth, its structure, processes, history and its place in the universe.

Related Fields of Earth Science:1.Physiography – study of the surface

features of the Earth, how they change and the processes that produce these surface features.

2.Geology - study of the composition, structure and history of the Earth. It studies the nature and properties of the materials making up the Earth, their distribution

throughout the globe and the properties that form change and transport them.

3. Paleontology – study of the history of life on Earth as gathered from the remains of living things called the fossils.

4. Oceanography – scientific study of the ocean and seas, their structure as well as the living things that dwell in them.

5. Meteorology – study of the atmosphere and its changes that bring about the formation of weather and climate.

6. Astronomy – study that deals with the heavenly bodies.

Importance of Earth Science:1.To apply what we know about the

Earth to improve our living conditions.2.Adds knowledge on how the world and

universe look like. It reveals land structure that can’t be seen by geologists like – land structures rich with deposits of valuable minerals; water areas where then temperature is favorable to increase the catch of species of plants.

3. Describe geologic events and can sometimes explain why events happen.

Instruments Used in Earth Science:I. Optical Telescopes – most important

tool in astronomical explorations. It can detect even the very faint light coming from any celestial object.

Hans Leppershey – Dutch lensmaker invented the first toy microscope.

Galileo - Italian astronomer, invented the first crude telescope.

Importance of telescope:Gathering the light being emanated by

the celestial object.Separating the components of the

objects into distinct parts ( resolving power).

Enlarging the object ( magnifying power) to see the image of the object which is to be observed or photographed.

Two major Types of Telescope:1. Refracting Telescope – magnifying

lens, eyepiece, enlarges the image of the object.

The largest refracting telescope is a 40-inch telescope at Yerkes Observatory in South Wisconsin, USA.

2. Reflecting Telescope - with curved mirror

Four types of reflecting microscope:

a.Prime focus telescopeb.Newtonian reflectorc.Cassegrainian reflectord.Coude reflector

The largest reflecting telescopes are found in Mt. Pastukhov, USSR ( 60M telescope), and at Mt. Palomar, California, USA ( 200 inch Hale telescope.

The Schmidth reflector is used for photographic purposes.

There are ten reflector around the world with mirrors equal to or larger than 3 meters (9 ft) in diameter.

There are 14 refractors around the world with objectives larger than 65 cm (26 in) in diameter.

The power of a 200-inch telescope is enormous – it can detect candlelight at a distance of 2 million light years.

II.Radio Telescope- The visible portion of the electromagnetic spectrum does not penetrate the atmosphere but radio waves easily pass through them.

Karl Jansky – American Engineer at Bell telephone laboratories discovered a steady hiss-like static coming from the Milky Way. 1931

1936:Grate Reber - American, constructed the first dish-shaped radio telescope in his backyard.

Largest radio telescope is located at Mt. Arecibo in Puerto Rico. It is 1000ft in diameter lying on top of the mountain.

III. Spectroscope- It is an instrument used to split light and

spread it into a set of colored lines called spectrum.

- A beam of light passing through a glass prism is separated into the color of the rainbow which is called spectrum. This proves that white light is a mixture of all colors.

A beam of light passing through a glass prism is separated into the color of the rainbow which is called spectrum. This proves that white light is a mixture of all colors.

Robert Bunsen – assembled the first spectroscope in 1859.

Spectroscopy – is the systematic study of the color spectrum composing the light emitted by an object. Used to determine the chemical composition of the object that produces light in the sky.

Used also the relative motion of the object that emits light in the sky.

Spectrograph – photographic study of the spectra produced by spectroscope.

Christian Doppler – made use of the principle of spectroscopy and pointed out that light wavelengths emitted by a celestial object are affected by motion. This means that light waves from a source may be spread or compressed depending on whether the object is moving toward or away from the Earth or the observer.

Blueshift – If a light source is approaching an observer, the light waves will crowd closer together. All spectral lines in the spectrum of an approaching light are shifted to the short wavelength end of the spectrum.

Redshift – If the light source is receding, the light will spread out. All spectral lines in the spectrum are stretched toward the longer wavelength end of the spectrum.

IV. Sonar – an echo-sounding device that measures the depth of the ocean floor.

V. Bathyscaph – a well-equipped under-sea craft that explores the details of the unpenetrable ocean floor.

VI. Coring instrument – gathers samples of materials from the ocean bottoms.

VII.Geiger Counter – used in determining the radioactivity and age of rocks or fossils.

VIII. Seismograph – records Earth's vibrations cause by the movements of the Earth, locates the origin of the earthquake and records its intensity

IX. Radar – determines the distance of an object in the sky by transmitting radio waves of an object and then detecting the radiation the object reflects back to the transmitter.

X.Thermocouple – used to study the temperature of stars.

XI. Photometer – used to study the brightness of stars.

XII. Artificial satellites – use to record or radio back information about the condition of the upper atmosphere and facilitate radio and telecommunication operations.