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Lecture 2

EESA01H3 Lecture Notes - Lecture 2: Scientific Method

Environmental Science
Course Code
Carl Mitchell

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Matter, Energy, andthe Physical Environment
Scientific Method: Technique for testing ideas by making observations and by gathering evidence.
The universe functions in accordance with fixed natural laws that
don’t change with time or place
All events arise from some cause and in turn lead to other events.
We use our senses and reasoning abilities to detect natural laws
that underlie cause-and- effect relationships observed in nature.
1. Make observations: set the scientific method in motion
2. Ask questions
3. Develop a hypothesis: answer questions by devising
explanations that can be tested. A hypothesis is an educated
guess to explain a phenomenon or answer a scientific question. A
scientist investigating algal growth in ponds might observe fertilizers applied on fields nearby.
“Agricultural fertilizers running into ponds cause the algae in the ponds to increase.”
4. Make predictions: Use the hypothesis to make predictions, statements that can be directly tested
“If agricultural fertilizers are added to a pond, the quantity of algae in the pond will increase.”
5. Test the predictions Gather evidence from experiment. Experiments are useful because they
establish causal relationships, changes in one variable cause predictable ones in another.
6. Analyze and interpret results Scientists record data from their studies to objectively determine
the strength and reliability of the patterns they find.
Testing Hypotheses
Manipulative experiment: choose and manipulate the independent variable…vs natural.
The scientific process does not stop with the scientific method
Theory: A widely accepted, well-tested explanation of cause-and-effect relationships, validated by
research. A theory combines many related hypotheses that’ve been tested and supported by data.
Properties of Water
Liquid from 0°C to 100°CWater-based biological processes occur in many conditions
exhibits strong cohesion facilitating the transport of chemicals in the environment.
High heat capacity to absorb a large amounts of heat with only small changes in temperature.
This stabilizes systems against change (organisms, ponds, lakes, or climate systems).
Molecules in ice are farther apart than in liquid form.: ice is less densereverse of most
compounds. Each molecule connected to neighboring ones by stable H bonds. Floating ice
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