WGU INTEGRATED PHYSICAL SCIENCES Flashcards
Key Terms
physics
chemistry
earth science
1.the study of forces and energy
2.the study of atoms and molecules
3. the study of Earth’s structure and composition, as well as the processes that change Earth
Controlled experiment
A controlled experiment is a test where one variable is changed while all other conditions remain constant, allowing researchers to pinpoint cause and effect.
Examples:
-Determining how fast different chemical pollutants dissolve in water
-Ice Melting: Compare the melting rate of ice in an empty glass versus a glass filled with water, while keeping room temperature, glass size, and ice shape the same.
-Plant Growth: Test a new fertilizer by growing two groups of identical plants under the same conditions, with only one group receiving the fertilizer.
These setups help ensure that any differences observed are due to the variable being tested.
Newton’s law
law of universal gravitation
Gravity is like an invisible rope that pulls things toward each other. Sir Isaac Newton found out that:
Bigger things pull harder: If you have something heavy, like the Earth, it pulls on other objects more strongly. Imagine if you had a super strong magnet.
The farther apart, the weaker the pull: If two things are far away from each other, they don’t pull on each other as hard. It’s like the strength of a whisper—it fades with distance.
So, whether it’s an apple falling from a tree or the Moon circling around the Earth, gravity is always working to pull things together.
________
states that every mass attracts every other mass with a force that depends on two key factors:
Mass: The force is directly proportional to the product of the two masses. This means that if you increase either mass, the gravitational force between them increases.
Distance: The force is inversely proportional to the square of the distance between the centers of the two masses. In other words, as the distance increases, the force decreases rapidly.
Mathematically, this relationship is expressed as:
This law has been confirmed by countless experiments and observations, from the way objects fall on Earth to the motion of planets in the solar system, and no experiments have ever contradicted it.
The theory of plate tectonics
The well-accepted scientific explanation for many characteristics of Earth’s crust states that the crust is broken into several large plates. These plates move slowly over the mantle below because of convection and other processes. Earthquakes and volcanoes are most common at places where the plates interact. Evidence from physics, chemistry, and geology supports this explanation.
Hypothesis
A hypothesis is an educated guess or prediction about why something happens, which can be tested through experiments. For example, you might hypothesize that “plants grow faster with more sunlight.”
Theory
A theory is a well-supported explanation for a set of observations or phenomena, developed after many experiments and a lot of evidence. For example, the theory of evolution explains how species change over time.
Law
A law is a statement that describes a consistent relationship observed in nature, often expressed in a mathematical formula. For example, Newton’s law of gravity describes how masses attract each other.
Observation
This is when you notice or measure something using your senses or tools. For example, seeing that leaves change color in the fall is an observation
Steps in the scientific process
noticing something (observation) to forming a testable idea (hypothesis), to developing a comprehensive explanation (theory), and finally to identifying consistent patterns (law).
Inference
An inference is a conclusion you reach based on evidence or observations. It involves using what you know to “read between the lines” and figure out something that isn’t directly stated. For example, if you see that the ground is wet and people are carrying umbrellas, you might infer that it has recently rained.
Why was the shrinking Earth idea replaced by the theory of plate tectonics?
The shrinking Earth theory suggested that Earth’s surface cracked as the planet cooled and contracted. However, it couldn’t explain evidence like seafloor spreading, matching continental shapes, and the patterns of earthquakes and volcanoes. Plate tectonics, which shows that Earth’s crust is divided into moving plates driven by mantle convection, better accounts for all these observations.
Valles Marineris on Mars
the longest known series of canyons in the solar system. The scientist found that Valles Marineris showed features found only in locations on Earth where major tectonic plates divide.
According to the theory of plate tectonics, volcanoes are especially likely to form
along plate boundaries because of rising magma
Scientists once believed they understood the chemical reactions that break down ozone in the stratosphere, a process that creates ozone holes. However, new measurements show…
that these reactions occur more slowly than the old model predicted. This discrepancy suggests that the original explanation was incomplete, and scientists now need to explore additional factors or processes that influence ozone destruction.
A woman does pushups by lowering her body to the floor using her arms and then pressing against the floor with her hands to push herself back up. Which force causes her to rise?
The upward force that the ground exerts on the woman
Force is a…
Push or pull
Air Resistance:
A force that opposes an object’s motion through the air. It increases with speed and depends on the object’s shape and size.
Example: A feather falls slowly through the air compared to a heavy stone, because air resistance slows it down.
Gravity:
A natural force that pulls objects toward each other. On Earth, it makes things fall and gives objects weight.
Example: When you drop a ball, it falls to the ground due to Earth’s gravitational pull.
Kinetic Friction:
A force that resists the sliding motion between two surfaces in contact. It depends on the nature of the surfaces and the force pressing them together.
Example: When you slide a book across a table, kinetic friction between the book and the table slows it down.
Magnetism:
A force exerted by magnets, which can attract or repel other magnetic materials or moving electric charges.
Example: A refrigerator magnet sticks to a metal door, demonstrating the attractive force of magnetism.
Kinetic energy is converted into thermal energy.
When you rub your hands together quickly, the motion (kinetic energy) is converted into heat (thermal energy) due to friction between your hands. Another example is when a car brakes; the friction between the brake pads and the wheels turns the car’s kinetic energy into thermal energy, heating the brakes.
Gravitational potential energy is converted into kinetic energy.
A common example is dropping a ball from a height. At the top, the ball has gravitational potential energy due to its position. As it falls, that energy converts into kinetic energy, which makes the ball speed up as it approaches the ground.
Chemical potential energy is converted into gravitational potential energy.
When you jump, the chemical energy stored in your muscles is used to push you upward. This energy first turns into kinetic energy as you move, and then it changes into gravitational potential energy as you gain height.
Another example is when a person climbs a flight of stairs. The energy stored in the food you eat (chemical potential energy) is used by your muscles to lift your body upward, increasing your gravitational potential energy as you gain height.
Consider a car driving up a steep hill. As the car ascends, the engine burns gasoline, converting the chemical energy in the fuel into mechanical energy that powers the car upward. As the car climbs, its height increases, and some of the energy is stored as gravitational potential energy.
What energy conversion occurs in a car’s engine?
Chemical potential energy is converted into thermal energy.
Elastic potential energy is converted into gravitational potential energy.
Imagine a toy catapult with a compressed spring. When the spring is compressed, it stores elastic potential energy. Once released, that energy propels a ball upward. As the ball rises, its speed slows down, and its energy changes into gravitational potential energy, which is highest at the peak of its flight.
Which kind of electromagnetic radiation carries information to and from a cell phone when it is used for a phone call?
Microwaves
Which type of wave has a longitudinal motion?
Sound waves
After natural disasters, first responders can locate survivors in the rubble by using thermal detectors. Because the victims’ bodies are warmer than their surroundings, the difference in temperature is detected by electromagnetic waves.
Which part of the electromagnetic spectrum is being detected?
Infrared radiation
Radio waves
Explanation: Radio waves are electromagnetic waves with long wavelengths and low frequencies. They are used mainly for communication because they can travel long distances and easily pass through the atmosphere.
Example: Radio broadcasts, Wi-Fi signals, and cell phone communications all rely on radio waves.
Infrared radiation
Explanation: Infrared radiation is electromagnetic radiation with wavelengths longer than visible light. It is commonly associated with heat, as it is emitted by warm objects, and is used in various technological applications.
Example: Infrared cameras capture thermal images, and remote controls use infrared signals to communicate with devices like televisions.
Ultraviolet radiation
Explanation: Ultraviolet (UV) radiation is a type of electromagnetic radiation with wavelengths shorter than visible light but longer than X-rays. It has higher energy than visible light and can cause chemical reactions, such as skin tanning or sunburn, and is used in various sterilization and forensic applications.
Example: UV radiation from the sun can lead to sunburn, while UV lamps are used to sterilize equipment and detect substances in forensic investigations.
X-rays
Explanation: X-rays are a form of electromagnetic radiation with high energy and short wavelengths. They can pass through soft tissues but are absorbed by denser materials like bones, making them valuable for imaging.
Example: X-rays are used in hospitals for diagnosing bone fractures and dental examinations, and in security scanners to inspect luggage.
Microwaves
Used in microwave ovens to heat food.
Employed in Wi-Fi signals and radar technology.
X-rays:
Utilized in medical imaging (like dental or bone X-rays).
Applied in airport security scanners and industrial inspections.
Infrared Radiation:
Found in remote control devices and thermal imaging cameras.
Used in night-vision equipment to detect heat.
Ultraviolet Radiation:
Present in sunlight; too much exposure can cause sunburn.
Used in sterilization lamps to disinfect surfaces.
Gamma Waves:
Explanation: Gamma waves are a type of electromagnetic radiation with extremely high energy, very short wavelengths, and high frequencies.
Example: Gamma rays emitted from radioactive substances (like cobalt-60) or cosmic events; they are also used in medical treatments such as cancer radiotherapy.
Transverse Waves:
Explanation: Transverse waves oscillate perpendicular to the direction of their travel.
Example: Waves on a string or rope, where the movement of the string is up and down while the wave travels horizontally; light waves are also transverse waves.
Sound Waves:
Explanation: Sound waves are mechanical waves that travel through a medium (like air or water) as compressions and rarefactions (longitudinal oscillations).
Example: The sound from a musical instrument or someone speaking.
Light Waves:
Explanation: Light waves are electromagnetic waves visible to the human eye. They travel through a vacuum and exhibit both wave and particle characteristics.
Example: Sunlight or the light emitted from a lamp.
Which statement correctly contrasts sound waves and electromagnetic waves?
Sound waves travel slower than electromagnetic waves.
Which is a characteristic of electromagnetic waves?
Transverse wave motion
what waves Travel faster through water than air
Sound waves travel faster in water than in air. This happens because water molecules are packed much closer together than air molecules, allowing the vibrations (sound) to pass along more quickly.
Longitudinal wave motion
sound waves
Can travel only through a vacuum
Electromagnetic Waves:
These waves can travel through a vacuum because they don’t need a material medium to move. Examples include light, radio waves, X-rays, and gamma rays.
What waves require a medium to travel?
mechanical waves like sound require a medium (air, water, or solids) to travel.
Which subatomic particle is located outside the nucleus?
Electron
What charge does a neutron have?
No charge
Proton
Position: Found in the nucleus of an atom.
Charge: Has a positive charge (+1).
Neutron:
Position: Also located in the nucleus alongside protons.
Charge: Has no charge (neutral).
Electron:
Position: Found in the electron cloud orbiting the nucleus.
Charge: Carries a negative charge (-1).
Ion:
Position: Can be any atom or molecule that has gained or lost electrons.
Charge: Has a net charge; if it loses electrons, it becomes a positive ion (cation), and if it gains electrons, it becomes a negative ion (anion).
Element:
Explanation:
A pure substance consisting of one type of atom that cannot be chemically broken down into simpler substances.
Example: Oxygen (O) or Gold (Au).
Compound:
Explanation:
A substance formed when two or more elements chemically combine in fixed proportions.
Example: Water (H₂O) or Table Salt (NaCl).
Mixture:
Explanation:
A physical combination of two or more substances that retain their individual properties and can be separated by physical means.
Example: Air or a bowl of mixed nuts.
since the ingredients in a cake are mixed physically without forming new chemical bonds, a cake is classified as a mixture.
A naturally occurring, inorganic solid with a specific chemical composition and a crystalline structure.
Example: Natural rock salt, Quartz (SiO₂) or Calcite (CaCO₃).
Mineral
Which example describes a compound?
A substance with only iron atoms
A substance with sodium atoms bonded to chlorine atoms
A substance with fluorine and nitrogen atoms that are not bonded together
A substance with iron and aluminum atoms that are not bonded to each other
A substance with sodium atoms bonded to chlorine atoms
Example: A substance with sodium atoms bonded to chlorine atoms is a compound (sodium chloride). When this compound occurs naturally as rock salt (halite), it is also classified as a mineral.
A substance with fluorine and nitrogen atoms that are not bonded together
Mixture:
Example: A substance with fluorine and nitrogen atoms that are not bonded together is a mixture since the atoms are physically combined, not chemically bonded.
A substance with iron and aluminum atoms that are not bonded to each other
Mixture
Example: A substance with iron and aluminum atoms that are not bonded to each other is also a mixture, as the atoms are simply mixed together without chemical bonds.
In which state of matter are particles close together, but able to slide past one another?
Liquid
Liquid:
Explanation: A state of matter where particles are close together but can move past one another.
Characteristics: Takes the shape of its container, has a definite volume, flows easily, and has moderate particle movement.
Solid:
Explanation: A state of matter with tightly packed particles in a fixed arrangement.
Characteristics: Has a definite shape and volume, particles vibrate in place, and maintains a rigid structure.
Gas:
Explanation: A state of matter where particles are far apart and move freely.
Characteristics: Expands to fill its container, has neither a fixed shape nor a definite volume, is compressible, and has high particle energy.
Plasma:
Explanation: An ionized gas consisting of free electrons and ions.
Characteristics: Conducts electricity, is affected by magnetic fields, exists at very high temperatures, and is commonly found in stars and neon signs.
what kind of chage is cooking an egg?
chemical change
Shredding paper
Evaporating water
Breaking a stick
physical change
Which type of bond is formed when valence electrons are shared between two atoms?
Covalent
Which properties will elements in group 2 share, based on location in the periodic table?
Good thermal conductivity
Good electrical conductivity
Ionic Bonds:
Explanation: Electrons are transferred from one atom to another, creating oppositely charged ions that attract each other.
Example: In sodium chloride (NaCl), sodium loses an electron to become Na⁺, and chlorine gains an electron to become Cl⁻, forming a strong electrostatic bond.
Covalent Bonds:
Explanation: Atoms share electrons to achieve a full outer electron shell, creating a stable bond.
Example: In a water molecule (H₂O), oxygen shares electrons with two hydrogen atoms.
Metallic Bonds:
Explanation: In metals, atoms release some electrons to form a “sea of electrons” that moves freely, binding the atoms together.
Example: In copper (Cu), the free electrons allow it to conduct electricity and heat, and give it malleability.
Mechanical Bonds:
Explanation: Unlike chemical bonds, mechanical bonds hold objects together through physical interlocking or entanglement rather than electron sharing or transfer. These bonds are common in macroscopic objects and certain supramolecular structures.
Example: A chain is held together by links that are physically interlocked. In chemistry, interlocked molecules called catenanes are an example of mechanical bonding.
Consider the location of chlorine (Cl) on the periodic table.
Which element has chemical properties that are similar to chlorine’s?
Fluorine (F)
A beaker contains 500 g of liquid water. An ice cube with a mass of 5 g is added to the water in the beaker.
How many grams of liquid water are in the beaker when the ice has melted?
505g
A chemist places 250 grams of liquid water into a beaker. The volume of the liquid water is 250 milliliters. The chemist then freezes the water. After it is frozen, the ice has a volume of 273 milliliters.
What is the mass of the ice?
250 grams
water expands when it freezes. As water cools below 4°C and turns into ice, its molecules arrange into a crystalline, hexagonal lattice. This structure creates more space between the molecules than in liquid water, causing the overall volume to increase by about
9%
When baking soda is added to vinegar, a chemical reaction occurs. The reaction produces carbon dioxide gas, and a liquid solution consisting mostly of water and a salt called sodium acetate.
How is mass affected in this reaction, according to the law of conservation of matter?
The total mass of baking soda and vinegar must equal the total mass of carbon dioxide and the liquid solution.
the law of conservation of matter
The law of conservation of matter states that matter is neither created nor destroyed during a physical or chemical change—it simply changes form. In any reaction, the total mass of the reactants equals the total mass of the products.
Example: When water freezes, it turns into ice. Although the water molecules rearrange into a different structure, no water is lost in the process, so the mass stays the same.
In which phase change is energy being absorbed from the surroundings?
Water boiling on an electric burner
What happens when wet clothes dry outside on a warm day?
The water in the clothes absorbs energy from the air and becomes a gas.
Earth formed from dust and gases surrounding the sun.
Which force pulled the dust and gases together to form Earth?
Gravitational
A pond freezing over in winter:
Phase Change: Freezing (liquid to solid)
Explanation: Water in the pond loses heat and forms ice as it cools below its freezing point.
Water boiling on an electric burner:
Phase Change: Vaporization (boiling: liquid to gas)
Explanation: As water is heated, its molecules gain energy and escape into the air as water vapor.
Molten glass solidifying into a vase:
Phase Change: Solidification (liquid to solid)
Explanation: The molten glass cools down, causing its molecules to slow and lock into a rigid structure.
Clouds forming on a summer day:
Phase Change: Condensation (gas to liquid)
Explanation: Water vapor in the warm air cools down, condensing into tiny liquid droplets that form clouds.
Melting:
Solid to liquid (e.g., ice melting into water).
Freezing:
Liquid to solid (e.g., a pond freezing over in winter).
Vaporization:
Liquid to gas (this includes boiling, like water on a burner, and evaporation, which happens at the surface)
Condensation:
Gas to liquid (e.g., clouds forming from water vapor).
Sublimation:
Solid directly to gas (e.g., dry ice turning into carbon dioxide gas).
Deposition:
Gas directly to solid (e.g., frost forming on a cold surface).
A galaxy consists of many stars in the same large region of space.
Which phenomenon leads stars to group together to form a galaxy?
Gravity between stars
Gravitational Force:
Explanation: A force of attraction between any two objects with mass. Its strength depends on the masses involved and the distance between them.
Example: The force that pulls an apple toward the Earth or keeps the planets in orbit around the sun.
Electrical Force:
Explanation: A force between charged particles, either attracting or repelling them depending on the type of charge.
Example: The attraction between the negatively charged electrons and positively charged protons in an atom, or static electricity making a balloon stick to a wall.
Magnetic Force:
Explanation: A force exerted by magnets and moving electric charges, which can attract or repel other magnetic materials or charges.
Example: The attraction between a refrigerator magnet and a metal surface, or the repulsion between the north poles of two magnets.
Frictional Force:
Explanation: A resistive force that occurs when two surfaces slide against each other. Its magnitude depends on the nature of the surfaces and the force pressing them together.
Example: The force that slows down a sliding book on a table or helps car tires grip the road.
Electromagnetic Force:
Encompasses both electrical and magnetic forces. It’s responsible for the forces between charged particles.
Examples: Attraction/repulsion between charges, magnets sticking to a refrigerator.
Strong Nuclear Force:
Binds protons and neutrons together in an atom’s nucleus, overcoming the repulsion between the positively charged protons.
Example: The force holding the nucleus of a hydrogen or helium atom together.
Weak Nuclear Force:
Responsible for certain types of radioactive decay and nuclear processes, such as beta decay.
Example: Processes in the sun that convert hydrogen into helium.
Friction
Friction, while important in everyday life, is not a fundamental force. It arises from electromagnetic interactions and the microscopic properties of surfaces.
What is true during summer in the northern hemisphere?
The northern hemisphere receives more direct sunlight than in the winter.
A geologist is doing a risk assessment for a location where the African plate is moving away from the South American plate.
Which risk description must the geologist give for this location?
There is high risk of volcanoes and low risk of large earthquakes.
Low risk of volcanoes and high risk of large earthquakes:
Example: The San Andreas Fault in California.
Simple Explanation: Here, the Earth’s plates slide past each other. This movement creates stress that leads to big earthquakes, but it doesn’t create the conditions needed for volcanoes.
High risk of both volcanoes and large earthquakes:
Example: The Cascadia Subduction Zone in the Pacific Northwest.
Simple Explanation: In this area, one plate is forced under another. This process builds up huge amounts of pressure that can cause strong earthquakes and also produce magma that leads to volcanoes.
Low risk of both volcanoes and large earthquakes:
Example: The Canadian Shield.
Simple Explanation: This region is far from any active plate boundaries, so there isn’t much movement to create big earthquakes or trigger volcanic activity.
A river flows across a region. As the river flows, it erodes the rock beneath it.
Which type of landform will develop if the river continues to flow along a straight path?
Valley
Valley:
How it’s produced: Valleys form when flowing water (rivers) or moving ice (glaciers) erodes the land over time.
Example: A river cutting through mountains creates a V-shaped valley, while glaciers carve out U-shaped valleys.
Dune:
How it’s produced: Dunes are created by wind moving and depositing sand. As wind blows across a sandy surface, it lifts sand particles and piles them up, forming dunes.
Example: Sand dunes in deserts or along coastlines.
Glacier:
How it’s produced: Glaciers form in areas where snowfall accumulates over many years. Over time, the snow compacts into ice, and gravity causes the mass of ice to slowly flow, eroding and shaping the landscape.
Example: Glaciers in polar regions or high mountain ranges like the Alps.
Meander:
How it’s produced: Meanders develop in rivers when the flowing water erodes the outer banks and deposits sediment on the inner banks, causing the river to bend gradually over time.
Example: The winding curves of a river in a flat plain.
Waterfall:
How it’s produced: Waterfalls occur when a river flows over a steep drop in elevation. This typically happens where layers of hard rock overlay softer rock that erodes faster, creating a sudden cliff over which water falls.
Example: A river flowing over a resistant rock layer, creating a cascading drop like Niagara Falls.
Where is metamorphic rock found in the rock cycle?
After heat and pressure
The rock cycle is
the process that continuously transforms rocks from one type to another over time. It shows how the three main rock types—igneous, sedimentary, and metamorphic—are interconnected.
In the rock cycle, any rock type can transform into another type—for instance, igneous rock can be weathered into sediments that form sedimentary rock; sedimentary rock can be changed into metamorphic rock under heat and pressure; and metamorphic rock can melt into magma that cools to form igneous rock again.
Igneous Rock:
Igneous rock is produced. After melting and cooling:
When rock melts into magma and then cools, it solidifies into igneous rock.
How it forms: When molten rock (magma or lava) cools and solidifies.
Example: Granite (formed inside the Earth) or basalt (formed from lava on the surface).
Sedimentary Rock:
Sedimentary rock is produced After erosion and deposition:Particles erode, are transported, and then deposited and compacted into rock.
How it forms: From particles of rock and minerals that are weathered, eroded, and then deposited in layers. These layers are compacted and cemented together over time.
Example: Sandstone or limestone.
Metamorphic Rock:
Metamorphic rock is produced After folding and cracking. The original rock is deformed by pressure, causing it to fold and crack, which changes its structure.
After heat and pressure:
Intense heat and pressure alter the original rock’s composition and texture without melting it.
How it forms: When an existing rock (igneous, sedimentary, or another metamorphic rock) is changed by high pressure, high temperature, or chemical processes, without melting.
Example: Slate, schist, or gneiss.
Through which layer of the atmosphere does a mountaineer climbing a tall mountain ascend?
Troposphere
A meteorologist is studying the formation of a hurricane.
Which layer of the atmosphere is the meteorologist studying?
Troposphere
Troposphere:
Description: The lowest layer of the atmosphere, extending from the Earth’s surface up to about 8-15 km.
Characteristics:
Contains most of the Earth’s weather (clouds, rain, snow, etc.).
Temperature generally decreases with altitude.
Example: The air you breathe and the weather you experience daily occur in the troposphere.
Stratosphere:
Description: The layer above the troposphere, reaching up to about 50 km in altitude.
Characteristics:
Contains the ozone layer, which absorbs and scatters ultraviolet solar radiation.
Temperature increases with altitude due to the absorption of UV radiation by ozone.
Example: Commercial airplanes often fly near the lower stratosphere to avoid weather turbulence.
Mesosphere:
Description: The middle layer of the atmosphere, extending from the top of the stratosphere up to about 85 km.
Characteristics:
Temperature decreases with altitude, making it the coldest layer of the atmosphere.
Meteors burn up in this layer, creating visible shooting stars.
Example: The brilliant streaks of light from meteors burning in the mesosphere on a clear night.
Thermosphere:
Description: The outermost layer of the atmosphere, starting around 85 km and extending to 600 km or more.
Characteristics:
Temperature increases significantly with altitude, though it would feel very cold because of the extremely low density of molecules.
Contains the ionosphere, which is important for radio communication as it reflects radio waves back to Earth.
Example: The beautiful auroras (Northern and Southern Lights) occur in the thermosphere, caused by charged particles interacting with Earth’s magnetic field.
During heavy rains, the soil on a farm is washed away into a nearby river.
Which parts of the water cycle result in this loss of soil?
Precipitation
Runoff
Precipitation:
Explanation: This is any form of water that falls from the sky. It can occur as rain, snow, sleet, or hail.
Example: When clouds become heavy with water droplets, they release rain during a storm.
Infiltration:
Explanation: This is the process by which water on the ground surface soaks into the soil.
Example: After a rainstorm, water seeps into the garden soil, helping plants get the moisture they need.
Runoff:
Explanation: Runoff is water that flows over the land surface, rather than soaking into the ground, usually because the soil is saturated or impermeable surfaces are present.
Example: After heavy rain, water may flow along streets and lawns, eventually reaching rivers or lakes.
Evaporation:
.
Explanation: Evaporation is the process by which water changes from a liquid to a vapor, typically due to heat from the sun.
Example: Water in a puddle gradually disappears on a sunny day as it evaporates into the air
Snow falls from the atmosphere and accumulates on a glacier.
Which part of the water cycle does this process represent?
Precipitation
A gardener is working in a garden on a hot, humid day. Suddenly, clouds begin to form. Within a few hours, gusty winds and a thunderstorm are passing through the area. After the storms pass, the weather is clear and much cooler.
What caused this change in weather?
A cold front moved through the area.
A high pressure system rests over the area:
Weather Changes: Generally clear skies, light winds, and dry conditions.
Example: A sunny day with little humidity.
A low pressure system rests over the area:
Weather Changes: Cloudy skies, increased chances of precipitation, and possibly stormy conditions.
Example: Overcast skies with rain or drizzle.
A cold front moved through the area:
Weather Changes: A rapid drop in temperature, a burst of showers or thunderstorms, and clearing skies afterward.
Example: A sudden cool down with a quick rain shower followed by sunny skies.
A warm front moved through the area:
Weather Changes: Gradual warming, widespread cloudiness, and light, steady precipitation.
Example: A slow increase in temperature with persistent, gentle rain.
A hiker needs to select a day for a hike. The hiker examines weather forecasts for the next several days.
Which day should the hike be planned for, if the hiker wants to hike on a clear day with no clouds?
A day when a high pressure system rests over the area
Which of these is an example of climate change caused by natural variation?
The low rainfall that helped produce the dust bowl in the American Great Plains
What is an example of climate change that can be caused by human activity?
Changes in average temperature from increases in atmospheric carbon dioxide
Which feature is common to all of the terrestrial planets?
A dense metallic core
Where are most of the asteroids in the solar system located?
Between Mars and Jupiter
Which renewable energy source is used to create electricity through the production of steam?
Geothermal
Variables in an Experiment
independent variable: the variable that is changed by the experimenter in an experiment
dependent variable: the variable that changes because of the independent variable
control variable: the variable that scientists do not wish to study that needs to either be eliminated or kept constant
Independent Variable:
The factor that the experimenter changes intentionally.
Example: In a plant growth experiment, the amount of water given to plants.
Dependent Variable:
The outcome that is measured in response to the independent variable.
Example: In the same experiment, the growth height of the plants.
Controlled Variables:
Other factors that are kept constant to ensure a fair test.
Example: The type of plant, soil, light, and temperature in the experiment.
controlled experiment:
an experiment in which a scientist intentionally changes one quantity and observes how another quantity changes
observational studies:
Explanation: Observational studies involve watching and recording behaviors or events as they naturally occur, without intervening or altering the situation. Researchers collect data by observing subjects in their normal environments.
Example: A study tracking the eating habits of people in a cafeteria to see which foods are most popular, without changing the menu or influencing their choices.
field studies:
Explanation: Field studies involve collecting data directly in the natural environment where the subjects or phenomena occur, rather than in a controlled laboratory setting. Researchers observe, measure, and sometimes interact with subjects in their real-world contexts, which can provide insights into natural behaviors and conditions.
Example: An ecologist studying the nesting habits of sea turtles on a beach, where data is gathered on the turtles’ behavior, environmental conditions, and human impacts, all in their natural habitat.
laboratory studies:
experiments that take place in a highly controlled, artificial setting
Explanation: Laboratory studies are research investigations conducted in a controlled setting, where variables can be carefully managed and manipulated. This allows researchers to isolate specific factors and determine cause-and-effect relationships with precision.
Example: A scientist testing the effect of different fertilizer amounts on plant growth in a lab, where temperature, light, and soil type are kept constant to accurately measure the fertilizer’s impact.
physical model:
a model that represents a real object or a phenomenon, usually on a smaller scale
conceptual model:
a model that can be used to visualize things that cannot be seen, such as atoms. This model can be visual (like diagrams or flowcharts) or verbal, making complex ideas easier to understand.
mathematical model:
a model that describes physical objects or phenomena using mathematical methods
computer model:
a model that uses computers to explain and predict complex systems, such as weather patterns and the detailed movements of objects in the solar system
direct proportionality:
a mathematical relationship between two variables whose ratio remains constant as their numerical values change (synonymous with positive correlation)
Explanation: Two quantities are directly proportional when they increase or decrease at the same rate. This means that if one quantity doubles, the other doubles as well. The relationship can be described with the equation
y=kx,
where k is the constant of proportionality.
Example: If you pay by the hour for a job, the total pay (y) is directly proportional to the number of hours worked (x). Doubling the hours worked will double the total pay.
inverse proportionality:
Explanation: Two quantities are inversely proportional when one increases as the other decreases, such that their product remains constant.
Example: The speed of a vehicle and the time it takes to travel a fixed distance. As the speed (x) increases, the travel time (y) decreases proportionally, keeping the product (distance) constant.
no correlation:
a lack of relationship between variables on a graph; a change in one value does not affect the other
proportionality constant:
a parameter that quantifies the relative changes in variables that are directly or inversely proportional
A proportionality constant is the fixed number that links two related quantities. It tells you how much one quantity changes when the other quantity changes. For example, if every apple costs $2, then $2 is the constant that tells you how much you’ll pay per apple. No matter how many apples you buy, the total cost is always that number multiplied by the number of apples.
origin of the plot:
the point on a graph where the value of both x and y axes are zero
a type of graph comparing two variables as data points in Cartesian, x-y coordinates
scatterplot
ratio:
a quantity that compares the values of two variables expressed as a fraction
temperature (Base Quantities)
Kelvin, K
electric current (Base Quantities)
ampere, amp
The ampere is the SI base unit for electric current. One ampere is defined as the current in which one coulomb of charge travels across a given point in one second. A coulomb is the SI unit for electric charge. Ampere is commonly abbreviated as amp. Common home appliances, such as toasters and refrigerators, typically draw from 5 to 20 amps, while an arc welder draws hundreds of amps, and a lightning bolt carries more than one hundred thousand amps.
amount of substance (Base Quantities)
mole, mol
It is used primarily when dealing with submicroscopic entities, such as atoms and molecules.
photometry (Base Quantities)
candela, cd
The candela is the SI base unit for photometry, the science of measuring light as perceived by the human eye. The candela is not used to quantify radio waves, X-rays, UV, and other types of electromagnetic radiation humans cannot see. The candela only measures the light that can be perceived by the human eye.
mega, M
1,000,000
kilo, k
1,000
deci, d
0.1
centi, c
0.01
milli. m
0.001
micro, (upside down h)
0.000001
nano, n
0.000,000,001
velocity:
an object’s speed and direction
acceleration occurs when an object
speeds up,
slows down, and/or
changes direction.
f you stand in one place and simply turn to face a different direction, you are accelerating!
One Newton is the weight of
Approximately one apple
Model
A good model explains current observations and predicts new ones. A model does not have to include every observed fact about a system it represents. It should be as simple as possible and, depending on its purpose, include only relevant characteristics of the systems. Scientists can use a variety of models, such as physical, conceptual, mathematical, and computational.
inverse proportionality
Two variables have inverse proportionality when a change in the value of one causes an opposite change in the value of the other. In other words, increasing one variable causes a decrease in the other variable and vice versa.
Direct proportionality
Direct proportionality is a mathematical relationship between two variables whose ratio remains constant as their numerical values change. That is, the two variables are linked such that changing the value of one results in a proportional change in the value of the other. The ratio between the variables thus remains constant. For example, if one variable increases, the directly proportional variable increases by an amount that keeps the ratio between them constant.
proportionality constant:
a parameter that quantifies the relative changes in variables that are directly or inversely proportional
scatterplot:
a type of graph comparing two variables as data points in Cartesian, x-y coordinates
Derived quantity
Volume, meter square
Velocity
An object’s velocity is its speed and direction
For example, if you drove straight east at a steady rate of 40 miles per hour, your speed would be 40 mph, but your velocity would be 40 mph due east
Acceleration
is a change in an object’s velocity.
Remember that velocity includes both speed and direction. So, any change in an object’s speed or direction is acceleration. In other words, acceleration occurs when an object
speeds up,
slows down, and/or
changes direction.
Force
Push or pull
The SI unit of force
The SI unit of force is the newton (abbreviated N). One newton is the approximate weight of a small apple.
kilograms are units of…
kilograms are units of mass, or how much matter is in an object. An object’s mass is different from the force acting on it. For example, the amount of matter in your foot is the same regardless of how hard you press down on the bathroom scale. In SI units, kilograms are a unit of mass, and newtons are the unit of force.
balanced forces
Forces that combine to produce a net force of zero are called balanced forces. Balanced forces cannot cause an object to accelerate
Newton’s first law of motion
Newton’s first law of motion describes how the forces acting on an object can affect its motion.
controlled experiment:
an experiment in which a scientist intentionally changes one quantity and observes how another quantity changes
independent variable:
the variable that is changed by the experimenter in an experiment
dependent variable:
the variable that changes because of the independent variable
control variable:
the variable that scientists do not wish to study that needs to either be eliminated or kept constant
The law of conservation of matter is …
- specific because it describes only how matter fails to be created or destroyed in a chemical reaction.
-Tested by experiment
and
-Intended to be universal
Which property must a testable statement have?
It is capable of being shown untrue.
If you see an object accelerating, then Newton’s first law tells you…
that there must be a nonzero force acting on it.
An example of Newton’s first law is that a hockey puck will continue to slide until stopped by a wall or a player’s stick. This is because of the low friction between the puck and the ice. This is an example of the first law because it illustrates that an object will remain in motion unless acted upon by other forces.
Is it necessary for a spacecraft to continue firing its engines to keep it moving toward its destination?
No. The spacecraft remains in motion when no net force is acting on it.
Two people are both pushing on a ball with equal force in opposite directions. On person suddenly stops pushing. What will happen to the ball?
A non-zero net force results in the acceleration of an object.
inertia
he tendency to keep the same motion—that is, to remain at rest or to maintain the same velocity
Newton’s first law is often called the law of inertia
mass vs weight
Unlike weight, mass does not vary with location. The mass of an object is the same on Earth, in orbit, or on the surface of the moon. The two sides of a balance will balance just the same on Earth as on the moon.
A balance like the one shown measures mass directly by comparing the weights of different masses. A typical bathroom or kitchen scale measures the bending, stretching, or compressing of a spring to determine the force exerted by the object being weighed, so it is actually measuring the force of gravity, not mass.
Mass and weight are measured differently. Mass is described using units of kilograms. Weight is described using force units such as pounds, ounces, or newtons. Common weight scales typically show markings in both pounds and kilograms (kg). Since kilograms are units for mass, not weight, these markings are accurate only on or near Earth’s surface. On the moon, a given mass in kilograms would correspond to a much smaller weight in pounds.
Newton’s Second Law states
that the acceleration of an object depends on the mass of the object and the amount of force applied.
Another example has to do with pushing objects of different masses. If you apply the same pushing force to a cardboard box and a refrigerator, which would you expect to accelerate more? The answer is the cardboard box because of its low mass relative to the refrigerator.
Accceleration = net force : mass
or net force = mass times acceleration
Newton’s third law states that
whenever one object (your hand, in this case) exerts a force on a second object (the block), the second object exerts a force of the same magnitude in the opposite direction on the first object.
as described by Newton’s third law…
…Every instance of pushing yourself by exerting a force on some other object depends on the other object exerting a force back on you of the same magnitude in the opposite direction at that very same instant
The tires push against the road, and the road pushes back in the opposite direction with a force equal in magnitude. The car accelerates forward because the road pushes it, as described by Newton’s third law.
When the net force on an object is zero, according to Newton’s First Law of Motion,
he object will maintain its current state of motion. That means:
If it’s at rest, it stays at rest.
If it’s moving at a constant velocity, it continues moving at that velocity.
Newton’s Third Law of Motion states:
For every action, there is an equal and opposite reaction.
This law applies whether or not the objects are moving.
A parachute is deployed to slow down a skydiver while descending toward the ground. What happens to velocity and acceleration while the skydiver is descending?
Will they be pointing upwards or downwards?
When a parachute is deployed, the skydiver is already moving downward (so their velocity is downward), but the parachute creates air resistance (drag) that opposes their motion.
This drag force acts upward, slowing the skydiver down.
Since they’re slowing down while falling, their acceleration is upward (opposite the direction of motion).
To measure the volume of irregularly shaped objects like ice cubes, you would use…
water displacement in a graduated beaker (or graduated cylinder)
Kinetic (moving) friction is the force of friction between two objects
Kinetic (moving) friction is the force of friction between two objects
Static (stationary) friction occurs between two objects touching each other but
not moving against each other. It is the force that prevents the two objects from starting to move. If you have ever tried to move a refrigerator, you know it requires more than just a little push to get it moving. The force of static friction between the refrigerator and the floor is more challenging to overcome than the force of static friction between a cereal box and a countertop.
Linear momentum is
the mass of an object times its velocity.
If two objects are moving at the same velocity, the more massive object has
more momentum.
law of conservation of momentum:
a scientific law that states that momentum is conserved when two or more objects collide
Elastic collision:
A collision where the total momentum and total kinetic energy are conserved
Inelastic collision:
A collision where the total momentum is conserved but the total kinetic energy is not conserved
Momentum - how to calculate
Momentum equals mass times velocity.
If the mass of an object is halved and its speed doubled, what will happen to its momentum?
It will not change.
The decrease in momentum is canceled by the increase in velocity.
What does the law of conservation of total linear momentum state?
That any momentum lost by one object in a collision will be gained by the other
The capacity to do work or to cause change is called
energy
work is…
Work is energy that is being used or converted.
work = force × displacement
In other words…
the more force applied, the more work is done. The greater the distance traveled, the more work is done.
Thermal energy depends on the mass and the average speed of the particles in a substance
For example, a large swimming pool full of water at 25°C has more thermal energy than a small cup of water at 25°C. A cup of boiling water at 100°C has more thermal energy than a cup of water at 25°C.
vacuum
the absence of matter
A WAVE
A wave is a repeating and periodic disturbance (oscillation) that travels from one location to another, transferring energy.
When the frequency of the wave increases, what happens to the amplitude?
STAYS THE SAME
What is the horizontal distance from one crest of a transverse wave to the next crest called?
Wavelength
What is the number of wavelengths that pass by a given point each second called?
The wave’s frequency
Electrons that occupy the outermost regions, those farthest from the nucleus (sometimes referred to as the outermost shell), of an atom are called
valence electrons.
Organic molecules
are primarily made of carbon atoms bonded to hydrogen, and often also include oxygen, nitrogen, or other elements.
What is the scientific definition of a pure substance?
A substance containing a single element or compound
What is the scientific definition of a mixture?
A substance in which atoms are not present in a fixed ratio
What is the scientific definition of a chemical?
A substance that contains one type of atom or a group of atoms in a fixed ratio
Which of the following is an example of a macroscopic property of matter?
The ability of a liquid to change shape when handled is an example of a macroscopic property.
Element
A pure substance made of only one kind of atom.
It cannot be broken down into simpler substances by chemical means.
Examples:
O₂ (oxygen gas)
Au (gold)
He (helium)
Compound
A substance made of two or more elements that are chemically bonded in a fixed ratio.
It can be broken down into its elements only by chemical reactions.
Examples:
H₂O (water) = hydrogen + oxygen
CO₂ (carbon dioxide) = carbon + oxygen
NaCl (table salt) = sodium + chlorine
Mixture
A combination of two or more substances (elements or compounds) that are not chemically bonded.
They can usually be physically separated.
Examples:
Salt water = salt (NaCl) + water (H₂O)
Air = nitrogen, oxygen, carbon dioxide, etc.
Trail mix = nuts, raisins, chocolate pieces
Solids
Microscopic Properties:
Particles (atoms or molecules) are tightly packed in a fixed, orderly arrangement.
Particles vibrate in place, but don’t move freely.
Strong intermolecular forces hold particles together.
👁 Macroscopic Properties:
Definite shape and definite volume.
Rigid and incompressible.
Doesn’t flow (unless it’s a very slow-moving solid like glass over time).
🔸 Liquids
🔬 Microscopic Properties:
Particles are close together, but not in a fixed position.
Particles can slide past one another, allowing movement and flow.
Moderate intermolecular forces—strong enough to hold together, but not rigid.
👁 Macroscopic Properties:
Definite volume but no definite shape — takes the shape of its container.
Flows easily, not easily compressed.
Surface tension and viscosity are visible properties due to particle interactions.
🔸 Gases
🔸 Gases
🔬 Microscopic Properties:
Particles are far apart and move freely in all directions.
Weak or no intermolecular forces between particles.
Particles move quickly and collide with each other and the walls of their container.
👁 Macroscopic Properties:
No definite shape or volume — expands to fill any container.
Compressible — can be squeezed into a smaller volume.
Low density compared to solids and liquids.
Particle speed (from fastest to slowest):
Gas > Liquid > Solid
A molecule
A molecule is a group of two or more atoms chemically bonded together.
👉A molecule = atoms stuck together by chemical bonds, acting as one unit.
Key Points:
The atoms can be the same element (like O₂) or different elements (like H₂O).
A molecule is the smallest unit of a substance that still has the chemical properties of that substance.
Some elements exist as a molecule
Examples:
O₂ – a molecule of oxygen gas (2 oxygen atoms)
H₂O – a molecule of water (2 hydrogen atoms + 1 oxygen atom)
CO₂ – a molecule of carbon dioxide (1 carbon + 2 oxygen atoms)
Pure substances
✅ Elements – Pure substances
Made of only one kind of atom
Example: O₂, Fe (iron), He (helium)
✅ Compounds – Pure substances
Made of two or more elements chemically combined in a fixed ratio
Example: H₂O (water), NaCl (salt)
elements that exist as molecules
BrINClHOF (pronounced “Brinklehoff”) — Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, Fluorine.
O₂ – oxygen gas
H₂ – hydrogen gas
N₂ – nitrogen gas
Cl₂ – chlorine gas
F₂ – fluorine gas
Br₂ – bromine (liquid at room temp)
I₂ – iodine (solid at room temp)
A pure substance
contains only one element or compound.
an element contains
only one type of atom
Covalent Bonds
Covalent Bonds – Brief Explanation
A covalent bond is a type of chemical bond where two atoms share electrons to achieve stability.
Usually occurs between nonmetal atoms.
Each atom contributes one or more electrons to be shared.
The shared electrons allow each atom to fill its outer energy level (like a full valence shell).
✅ Examples:
H₂O (water) – oxygen shares electrons with two hydrogen atoms.
O₂ (oxygen gas) – two oxygen atoms share two pairs of electrons (a double bond).
CH₄ (methane) – carbon shares electrons with four hydrogen atoms.
🔑 In short:
Covalent bond = shared electrons between nonmetals to form a stable molecule.
Which of the following statements about molecules are correct?
H2O
A molecule forms when electrons are shared in a covalent bond.
A molecule can consist of more than two atoms.
Not all molecules are compounds.
What are the compound elements for an ionic compound?
Both metals and nonmetals
What is the chemical bond type for a molecule?
Covalent bond
periodic table
Each row is called a period, and each column is called a group.
- solar system:
- planet:
- moon:
- asteroids:
- comets:
- Galaxy
- Orbit
- Meteor
- the collection of objects that orbit a star
- a large, spherical object that orbits a star
- a naturally formed object that orbits a planet
- very small, rocky bodies that orbit the sun
- relatively small, icy, dusty bodies that travel around the sun in very elliptical orbits
- a collection of hundreds of billions of stars that are clustered together by gravity
- when gravity causes one celestial body to move around another in a nearly circular path
- A shooting star
erosion
is the mechanism responsible for the transportation or removal of material. Erosion can be caused by liquid water, glaciers, wind, or gravity
weathering
is the breakdown of a material in place
he creation of sand dunes is a common example of
an aeolian process
1.sedimentary rocks:
2.metamorphic rocks: rocks that have been changed from their original form and typically occur when a rock is partially buried and exposed to elevated temperatures and pressures that are not extreme enough to melt the rock completely
1.rocks made up of weathered particles, such as sand, silt, clay, gravel, cobbles, or even occasionally boulders, that have been cemented together into hard rock
