science flashcards
What is conduction?
“Direct heat transfer between neighboring atoms or molecules with energy transferred from hot to cold particles through collisions.””
Define radiation in terms of heat transfer.
The release of electromagnetic energy or thermal energy, which can occur through any medium or in a vacuum.
What are radio waves used for in everyday life?
Broadcast radio and TV, military communications, mobile phones, and navigation.
What is a unique property of microwaves?
Microwaves are absorbed by water and can penetrate the atmosphere, making them suitable for satellite communication and radar.
What are the primary uses of infrared radiation?
Infrared is used for heating, remote sensing, and security systems.
How does visible light benefit humans?
Visible light allows us to see and is used in lasers and fiber optic networks.
What is ultraviolet radiation used for?
Used in sterilization/disinfection, medical therapy, and photography.
What are X-rays commonly used for?
Medical imaging, cancer treatment, and astronomy devices.
How are gamma rays used in medicine?
Detecting and treating cancer as they carry high energy and penetrate most materials.
What does voltage measure in a circuit?
The potential energy difference in an electrical circuit, measured in volts (V).
What is the function of current in an electrical circuit?
The rate at which electrons flow, measured in amperes (A).
What is resistance in an electrical circuit?
Opposition to the flow of current, measured in ohms (Ω).
What is the theory of plate tectonics?
The Earth’s lithosphere is divided into plates that move due to convection currents in the mantle.
What evidence supports plate tectonics?
Similar fossils and rock formations on distant continents, seafloor spreading, and the alignment of earthquakes with plate boundaries.
Who proposed the theory of continental drift?
Alfred Wegener in 1915.
Why was the continental drift theory initially rejected?
It lacked an explanation for why continents would move.
What technological advancements aid the study of tectonic plates?
Seismometers, satellite sensing, and computational modeling.
What is the biosphere?
The realm of every living organism, including plants, animals, and microbes, impacting other Earth systems.
What does the atmosphere do for Earth?
Protects from UV rays, facilitates the water cycle, and allows life to thrive by maintaining climate stability.
What is the lithosphere?
The Earth’s crust and upper mantle, containing soil and nutrients for ecosystems.
What is the hydrosphere?
All water on Earth, essential for life and cycling nutrients within ecosystems.
What role do cyclones play in Earth’s systems?
Cyclones disrupt weather patterns, contaminate water, erode landscapes, and destroy habitats.
How do earthquakes impact Earth’s four spheres?
Earthquakes create tsunamis, disrupt water quality, erode soil, and damage ecosystems.
Define the oxygen cycle.
The cycle through which oxygen is produced by plants, consumed by animals, and cycled back into the atmosphere.
Explain the nitrogen cycle.
Nitrogen is absorbed by plants from soil, consumed by animals, and returned to the soil through decomposition.
What is an energy pyramid in an ecosystem?
A representation of energy flow, showing producers at the bottom and apex predators at the top.
Why are apex predators less common than primary consumers?
Only 10% of energy transfers up each trophic level, limiting higher-level predators.
What is a trophic cascade?
An ecological phenomenon where changes at one level affect multiple levels in an ecosystem.
What happens when an abiotic factor, like temperature, changes drastically in an ecosystem?
It can disrupt food webs, alter species composition, and impact plant and animal survival.
What is an atom?
The smallest unit of a chemical element, consisting of protons, neutrons, and electrons.
Where are protons and neutrons located in an atom?
In the nucleus, which is the center of the atom.
What does the atomic number of an element represent?
The number of protons (and electrons in a neutral atom) in that element.
How is the periodic table organized?
By increasing atomic number and grouped by similar chemical properties.
What are alkali metals?
Highly reactive metals found in group 1 of the periodic table, excluding hydrogen.
What are halogens?
Elements in group 17 (or 7) that are very reactive and readily form salts with metals.
What is a neutralization reaction?
A reaction between an acid and a base producing a salt and water.
Write the general equation for an acid-metal reaction.
Acid + Metal → Salt + Hydrogen
What does an acid-carbonate reaction produce?
A salt, water, and carbon dioxide.
How do you write a word equation for a chemical reaction?
List the reactants, identify the reaction type, predict the products, and use an arrow to show the reaction.
What is Democritus known for in atomic theory?
Proposing the existence of indivisible particles called atoms, though lacking experimental proof.
Who discovered the electron?
J.J. Thomson, through the Cathode Ray Experiment.
What was Rutherford’s contribution to atomic theory?
Discovered the proton and proposed a nucleus-centered atomic model.
Who introduced electron shells in the atomic model?
Niels Bohr, showing electrons orbit in fixed levels.
What discovery did James Chadwick make?
The neutron, a neutral particle in the nucleus essential for atomic mass.
What does the Bohr model describe about electron movement?
Electrons orbit in fixed shells, with higher shells holding more energy.
What does the modern quantum mechanical model of the atom involve?
Electron clouds, where electrons are likely to be found, as per Schrodinger and Heisenberg.
What is the main product of a neutralization reaction?
A salt and water.
Why do only reactive metals undergo acid-metal reactions?
They displace hydrogen easily, unlike non-reactive metals.
How are acids and carbonates used in construction?
Carbonates react with acidic pollutants to strengthen cement structures.
How does convection work in fluids?
Hot fluids expand and rise due to lower density.
