Investigating SCIENCE MOD 5-6 FINAL

What factors led the scientists of Marshal and Warren to investigate these topics?

The high prevalence of ulcers and the failure of existing treatments (acid suppression therapy) to provide a cure led them to investigate.

What key observations and methods did Marshall and Warren use in their investigation?

Observation: Warren noticed spiral bacteria (later identified as Helicobacter pylori) in stomach biopsies.

Experimental Testing: Marshall cultured H. pylori from patient samples.

Self-Experimentation: Marshall ingested the bacteria, developing gastritis as evidence of causation.

Treatment Trials: They showed that antibiotic treatment could cure ulcers.

What were the major impacts of Marshall and Warren’s findings?

Their work provided definitive evidence linking H. pylori to peptic ulcers, revolutionized ulcer treatment with antibiotics, challenged established medical dogma, and ultimately led to a Nobel Prize in 2005.

What factors led the scientists of Van Helmont (Plant Growth) to investigate these topics?

Early theories suggested plants grew by taking mass from soil, but this was untested. He wanted to determine the true source of plant mass.

What was Van Helmont’s experimental methodology and its key findings?

Method: He planted a willow tree in a known mass of dried soil, watered it consistently for five years, then reweighed both the tree and soil.

Findings: The tree’s mass increased significantly while the soil mass remained nearly unchanged, suggesting water (and later, we know, carbon dioxide) was a key contributor to plant mass.

How did Van Helmont’s experiment contribute to later scientific developments?

It laid the foundation for understanding photosynthesis, showing the importance of quantitative experiments and challenging the soil-centric view of plant growth.

What led Percy Spencer to explore the effects of microwaves?

Working with radar technology during World War II, Spencer observed an unusual heating effect—his chocolate bar melted while near active radar—which sparked his curiosity about the potential of microwave radiation.

Describe Spencer’s key experiments and their outcomes.

• Observation: Noticed a chocolate bar melting near a radar set.

• Experimentation: Tested microwave effects on popcorn and other foods.

• Development: Designed a metal enclosure to control the microwaves, leading to the invention of the first commercial microwave oven.

What impact did Spencer’s discovery have on technology?

It revolutionized food preparation, demonstrating how accidental observations could lead to significant technological innovations and change everyday life.

Why did Eratosthenes investigate Earth’s circumference?

Ancient debates on whether Earth was flat or spherical spurred him to use geometry and observations of shadows to provide a more accurate measurement of Earth’s size.

How did Eratosthenes calculate Earth’s circumference?

He observed that on the summer solstice, sunlight reached the bottom of a well in Syene but cast a shadow in Alexandria. By measuring the shadow’s angle (7.2°) and estimating the distance between the two cities, he calculated the circumference as roughly 40,000 km.

What is the significance of Eratosthenes’ experiment?

It provided one of the earliest accurate estimates of Earth’s size, demonstrating the power of geometric reasoning in scientific inquiry.

What question did Christian Doppler set out to answer with his investigation?

Doppler sought to understand why the frequency of sound (and later, light) waves changes when the source moves relative to an observer.

What methodology did Doppler use in his experiments?

He observed changes in the pitch of sound from moving sources (e.g., using a moving train and musicians) to illustrate how waves compress when approaching and stretch when receding.

How has the Doppler Effect impacted modern technology and science?

It is fundamental to technologies such as radar, sonar, and Doppler ultrasound in medicine, as well as in astronomical observations through redshift and blueshift analyses.

What led Priestley to investigate the gases involved in combustion?

The prevailing phlogiston theory could not adequately explain combustion, prompting Priestley to explore the nature of gases released during burning.

Describe Priestley’s experimental process in his oxygen discovery.

He heated mercury oxide in a closed container and collected the gas released. Noticing its ability to sustain a flame and its effects on respiration, he identified this gas as essential for combustion.

What was the broader impact of Priestley’s discovery?

His findings challenged the phlogiston theory, paved the way for modern chemistry (influencing Lavoisier’s work), and helped establish the role of oxygen in both combustion and respiration.

How do computerised simulations enhance our understanding of Earth’s geological history?

They use large datasets (from radiometric dating to satellite imaging) to model variables such as plate tectonics and erosion, providing accurate reconstructions and predictions that support and refine geological theories.

What role did X-ray diffraction play in discovering the structure of DNA?

X-ray diffraction provided crucial evidence—especially through Rosalind Franklin’s “Photo 51”—revealing the double-helix structure of DNA, which underpinned modern genetics and biotechnologies.

How did technologies to detect radioactivity contribute to the development of atomic theory?

Instruments like Geiger counters and cloud chambers allowed scientists to measure radioactive decay and detect subatomic particles, leading to the refinement of atomic models and the development of nuclear technologies.

What is the significance of the Large Hadron Collider in modern physics?

The LHC enabled the discovery of the Higgs boson by creating high-energy collisions that replicate early-universe conditions, thereby confirming key aspects of the Standard Model and driving further advances in particle physics.

How did the laws of refraction and reflection contribute to advancements in microscopes and telescopes?

Refraction: Explains how light bends when passing between media, critical for lens design.

Reflection: Provides principles for mirror-based telescopes.
These laws enabled scientists to build instruments that vastly improved our ability to observe both microscopic and astronomical objects.

In what ways has our understanding of radioactivity influenced modern technologies?

Knowledge of radioactive decay has been applied in radiotherapy for cancer treatment, the development of nuclear bombs, and nuclear power generation, all stemming from fundamental research in atomic structure and energy release.

How did the discovery of DNA’s structure lead to advancements in biotechnology?

Revealing the double-helix model paved the way for genetic engineering, such as the development of GMOs, CRISPR gene editing, and other biotechnologies that have revolutionised medicine, agriculture, and forensic science.

How do Newton’s Laws impact the design of earthquake-resistant buildings?

First Law (Inertia): Buildings remain static unless acted upon, emphasizing the need for external shock absorption.

Second Law (F = ma): Helps calculate forces during an earthquake.

Third Law (Action-Reaction): Guides the use of counterforces (e.g., base isolators) to reduce damage.
These principles have led to technologies and materials that enhance structural resilience.

What key considerations should be included when designing a practical investigation using available technologies?

• Variables: Clearly identify independent and dependent variables (e.g., temperature on reaction rate or gas volume).

• Quantitative Data: Ensure methods produce measurable, numerical data.

• Technology: Use appropriate tools (sensors, data loggers, simulation software) to capture accurate data.

• Methodology: Justify the chosen method based on the investigation’s subject and context, and consider peer-reviewed literature to validate the approach.

How do the methodologies of Marshall & Warren, Van Helmont, and Spencer compare in terms of experimental design?

• Marshall & Warren: Combined observational pathology with controlled experiments (including self-experimentation) to establish causation between H. pylori and ulcers.

• Van Helmont: Used a quantitative, long-term mass-balance experiment to challenge existing assumptions about plant growth.

• Spencer: Capitalised on serendipitous observation in a high-tech setting (radar) and then conducted controlled tests with food items, leading to a practical technological innovation.

What are the strengths and weaknesses of self-experimentation as used by Marshall and Warren compared to controlled laboratory experiments?

• Strengths: Provides direct evidence of causation, can be faster and more cost-effective in early exploratory phases.

• Weaknesses: Raises ethical issues, limits reproducibility, and poses risks to the experimenter.

• Controlled Experiments: Offer more reproducible data and are generally safer, though they may require more resources and time.

What distinguishes quantitative from qualitative data in scientific investigations, and why is quantitative data often preferred for measuring effects?

• Quantitative Data: Numerical and measurable, allowing precise statistical analysis (e.g., weight changes in Van Helmont’s experiment, angles in Eratosthenes’ measurement).

• Qualitative Data: Descriptive, providing context or insights into patterns (e.g., observational notes on symptom changes in self-experiments).

• Preference for Quantitative Data: It offers clarity, reproducibility, and the ability to establish statistical significance in the investigation’s results.

Why is it important to justify the chosen methodology based on the subject and context of an investigation?

Different investigations require different approaches:

• Experimental testing is best when controlling variables is essential.

• Fieldwork may be needed for natural observations (e.g., Doppler’s sound observations).

• Computer simulations are ideal when dealing with vast datasets or inaccessible phenomena (e.g., Earth’s geological history).

• Justification ensures that the data collected is relevant, reproducible, and valid for answering the research question.

How have developments in technology influenced the design of scientific investigations?

• Enhanced Measurement: Instruments like Geiger counters and digital sensors provide accurate, real-time data.

• Computer Simulations: Allow complex models (like Earth’s geological history) to be tested without physical constraints.

• Data Analysis: Advanced software tools improve the ability to process large datasets and extract meaningful patterns.

• Feedback Loop: Technological advances both support and are driven by new scientific theories, as seen with the LHC and the discovery of the Higgs boson.

Peptic ulcers were investigated due to the high prevalence of ____.

ulcers and failed existing treatments.

Marshall and Warren observed that existing treatments for ulcers were largely ____.

ineffective.

Eratosthenes measured the Earth’s circumference using shadows cast by the sun, specifically at ______ and Alexandria.

Syene.

Doppler's investigations focused on the change in frequency of waves due to the ____ of the source.

motion.

Priestley initially investigated gases because the phlogiston theory could not explain ____.

combustion.

Van Helmont conducted experiments to determine that plants gain mass primarily from ____.

water.

Spencer’s interest in microwaves was sparked by observing the melting of a ____ near radar equipment.

chocolate bar.

The objective of experimental testing in science is to determine ____.

causal relationships.

Investigative methods can vary, such as using fieldwork to study natural ____.

phenomena.

Quantitative data is preferred for measuring effects because it provides ____.

measurable outcomes.

Technological advancements have improved our ability to gather and analyze ____.

scientific data.

The Hadron Collider has enhanced our understanding of particle physics through ____.

high-energy collisions.

X-ray diffraction was crucial in revealing the double-helix structure of _____.

DNA.

Developments in technology drive the need for further advancements in scientific ____.

theories.

The laws of refraction and reflection impacted the design of ____ and telescopes.

microscopes.

Priestley’s work on oxygen challenged the prevailing ___ theory of combustion.

phlogiston.

Computer simulations allow us to model complex systems such as _______ geological history.

Earth's.

Doppler's effect has applications in medical technologies such as _____.

ultrasound.

Radioactivity has implications for both energy generation and _______.

medical treatment.

Newton's laws inform engineering practices for designing structures that resist _____.

earthquakes.

Scientific investigations often require justifying methods based on the context and _____.

research subject.

The objective of Marshall and Warren’s investigation was to prove the link between H. pylori and _____.

peptic ulcers.

In investigating plant growth, Van Helmont used a long-term ______ experiment.

mass balance.

Spencer's controlled experiments with food aimed to understand the effects of microwaves on _______.

cooking.

Eratosthenes' method involved measuring the angle of the shadow, which was ____ degrees.

7.2.

In evaluating scientific methodologies, one must consider the relevance of peer-reviewed ______.

literature.

Assessing the impact of technology on science requires examining how they contribute to ______ evidence.

theory.

Technological developments enable the construction of ____ models for better predictive analysis.

computerized.

Data collected in investigations should align with goals to ensure _____ and validity.

relevance.

Advances in technology have led to improved methods for detecting _____.

radioactivity.

In investigations, measuring changes in temperature can affect the _____ of a reaction.

rate.

The discovery of DNA's structure has led to the development of new ______ in biotechnology.

applications.

High-energy particle collisions at the LHC have confirmed elements of the Standard ______.

Model.