Question

Each of the following statements may either be a hypothesis (H), a theory (T), or an observation (O). Use one of these letters to identify each statement. Briefly explain each choice. a. A scientist proposes that a recently discovered large ring-shaped structure on the Canadian Shield is the remains of an ancient meteorite crater. b. The Redwall Formation in the Grand Canyon is composed primarily of limestone. c. The outer part of Earth consists of several large plates that move and interact with each other. d. Since 1885 , the terminus of Canada's Athabasca Glacier has receded 1.5 kilometers.

Short answer

a: H, b: O, c: T, d: O

Step-by-step solution

Identifying the Type of Scientific Statement

To solve this problem, we'll categorize each of the given statements as a hypothesis (H), theory (T), or observation (O). Here’s how these are defined: - A **hypothesis** (H) is a proposed explanation for a phenomenon made on the basis of limited evidence as a starting point for further investigation. - A **theory** (T) is a well-substantiated explanation acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation. - An **observation** (O) is the act of noting and recording something with instruments or the human senses, often seen as a statement of fact.

Analyzing Statement (a)

Statement (a): "A scientist proposes that a recently discovered large ring-shaped structure on the Canadian Shield is the remains of an ancient meteorite crater." This statement is a **Hypothesis (H)**. It is a proposal made by a scientist based on initial evidence suggesting a possibility that needs further investigation to be confirmed.

Analyzing Statement (b)

Statement (b): "The Redwall Formation in the Grand Canyon is composed primarily of limestone." This statement is an **Observation (O)**. It is a stated fact that can be verified through examination or measurement of the Redwall Formation's composition.

Analyzing Statement (c)

Statement (c): "The outer part of Earth consists of several large plates that move and interact with each other." This statement is a **Theory (T)**. It refers to the Plate Tectonics Theory, which is a well-established and widely accepted scientific explanation that has been extensively supported by evidence.

Analyzing Statement (d)

Statement (d): "Since 1885, the terminus of Canada's Athabasca Glacier has receded 1.5 kilometers." This statement is an **Observation (O)**. It provides a specific quantitative measurement of the glacier’s recession over time.

Key concepts

Hypothesis

A hypothesis is an idea that a scientist proposes to explain a specific observation. It is often based on initial evidence or an idea that sparks curiosity. A hypothesis serves as a starting point for further investigation. It is crucial because it initiates the process of scientific inquiry. Forming a hypothesis involves asking a question and making an educated guess to answer it.
For example, when a scientist observes a unique structure on the Canadian Shield and suggests it might be a meteorite crater, they are forming a hypothesis.

• Hypotheses are not yet proven.
• They are tested and scrutinized through experiments and observations.
• A single hypothesis can lead to multiple experiments.

Theory

A theory in science is an explanation of a natural phenomenon that has been repeatedly tested and confirmed through observation and experimentation. Theories are comprehensive and generalize a lot of information, making sense of complex data.
The theory of Plate Tectonics is an excellent example. It explains how the Earth’s surface is made up of plates that move and interact. This theory is widely accepted because of the ample evidence supporting it, including fitting continental shapes, similar fossils found on different continents, and the record of earthquakes and volcanoes.

• Theories are broader in scope than hypotheses.
• They explain the 'why' and 'how' behind a wide range of phenomena.
• Theories can evolve over time as new evidence is discovered.

Observation

Observations are the raw data of the scientific world, providing direct information about the natural world. They involve noting and recording phenomena through our senses or instruments.
For instance, observing that the Redwall Formation in the Grand Canyon is primarily limestone involves examining the rock layers and directly recording this fact. Observations are crucial because they provide the facts that scientists use to test their hypotheses and theories.

• Observations are often seen as factual and straightforward.
• They can be qualitative (descriptive) or quantitative (numerical).
• Observations help gather evidence needed to support or refute a hypothesis or theory.

Plate Tectonics

The theory of plate tectonics describes the large-scale movement of Earth's lithosphere, which is divided into several plates that glide over the semi-fluid asthenosphere below. This theory revolutionized our understanding of the dynamic Earth by explaining the occurrence of continents, mountains, earthquakes, and volcanoes.
Plate tectonics explains the shifting puzzle pieces that are the continents. It also helps us understand natural disasters and why they occur where they do. For instance, the edges of these tectonic plates are often sites of seismic activity and volcanism.

• Plates can move apart, collide, or slide past one another.
• Plate boundaries are categorized as divergent, convergent, or transform.
• Features like the Himalayas and the Mid-Atlantic Ridge are results of plate tectonics.