Earth Science – Intro Notes



Earth Science – Notes for Chapters 1 & 2

Earth Science is composed of 4 main categories:

1. Geology – Study of rocks; including minerals, volcanoes, land forms, natural resources, and plate tectonics.

Geosphere (physical features of Earth not including water; examples include: (Listed above)

2. Astronomy – Study of outer space; including star formation, planets, our solar system and universe.

3. Meteorology – Study of Earth’s atmosphere and weather.

Atmosphere (Gaseous envelope that surrounds the Earth (Primarily Nitrogen Carbon Dioxide and Oxygen)

4. Oceanography – Study of the oceans and currents (temperature and salinity of the oceans)

Hydrosphere (all the water in the Earth’s system).

a. Sources of water include: Oceans, lakes, rivers, ice/snow, ponds, groundwater systems.

All 4 of these branches of Earth Science are interrelated! Sometimes there is not a clearly defined boundary separating them. The relationship between these branches of Earth Science can be viewed in the BIOSPHERE (all living objects in the Earth system).

Examples of how different spheres interact with one another:

1. Volcanoes erupt (geosphere) – gas and ash are released into the air (atmosphere) – lava and ash fall onto a city of people (biosphere)

2. Plants (biosphere) use water ( hydrosphere) and carbon dioxide (atmosphere).

3. How might the hydrosphere interact with the geosphere; geosphere with hydrosphere?

a. Hydrosphere may cause erosion on the geosphere.

b. An Earthquake or falling rocks may change the course of a river.

Systems and Models:

A system is a kind of model. A system can be defined as part of the universe that can be studied separately. Scientists describe objects in the natural world by using models such as open and closed systems.

1. Open System – The system and its surroundings freely exchange matter and energy.

a. Examples include: Open jar of tea. Boiling water.

2. Closed System – Energy may enter the system; however energy does not leave the system. Also, matter cannot be added or subtracted from the system.

a. Examples include: Closed jar of tea, unopen can of soda, lightbulb.

What kind of system is Earth?

The Earth is considered a closed system (but not entirely). What properties of the Earth make it a closed system?

1. Energy comes into the system and is absorbed.

2. Resources are finite (water!)

What properties of the Earth are NOT reflective of a closed system?

1. Meteors can enter the Earth system (mass)

2. Some energy can escape.

The Water Cycle:

The driving force of the water cycle is the sun. The sun shines on bodies of water or (ice/snow), and the water evaporates (becoming water vapor). Water vapor rises into the atmosphere and cools; when the vapor cools it forms clouds. When conditions are right, the clouds release their water vapor and precipitation begins to fall.

When rain falls to the Earth and flows over the ground into a body of water, it is called runoff Examples include: Streams, rivers, groundwater.

Some of the water evaporates again quickly or is breathed out by the leaves of plants

(transpiration). Evaporation and transpiration are known together as the process of

evapotranspiratioon

Remember: Water is never created or destroyed – it only changes its state (solid, liquid, gas).

How do scientists study the Earth and other things?

Science can be thought of as problem solving using educated guesses until some other research comes along to disprove the ideas.

Observations – A scientist observes things in his surroundings. Example (noticing the ground is wet in the morning)

Identify a problem – This should be in the form of a question. “Why is the ground wet some mornings, but not others?

Develop a hypothesis – A hypothesis should be written in using an “if and then” statement. “If the temperature is 50 degrees and the humidity is 60%, then there will be dew”

Design and run an experiment – An experiment will be designed with independent and dependent variables. An experiment should be conducted multiple times to ensure valid results.

Collect and Analyze the data – This is your “Results” section. In this section you will show the data you collected, you are not making any references to your hypothesis at this point.

Conclusion – Your conclusion should be a summation of your results. Was your hypothesis correct, what can you infer about the data you received?

Theories and Laws:

When a hypothesis has been tested over and over again (successfully), the hypothesis may be considered a theory. This means that there is substantial evidence suggesting that the theory is true; however it is still possible that evidence will arise that disproves the theory.

A law explains how the world behaves under certain conditions. There are no exceptions that disprove scientific law. An example of a scientific law is gravity.

Testing the Scientific Method using variables and constants

Variable – Anything in an experiment that changes.

Independent Variable – The independent variable is the variable changed by the scientist in an experiment. In our helicopter lab, we changed the number of paperclips. The number of paperclips was the independent variable.

Dependent Variable – The dependent variable is the variable that changes as a result of the independent variable. The dependent variable is the change that we measure. In our helicopter lab, the speed of the helicopter was influenced by the number of paperclips. We therefore measured how long it would take to fall. Fall speed was the dependent variable.

Constant or Control – Constants and controls do NOT change in an experiment. In our helicopter lab, we dropped the helicopter from the same height each time, and we used the same helicopter each time. Constants ensure that the data collected is consistent throughout the experiment.

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