6th Grade Science Final Exam Study Guide

Gravitational Force

Attraction pulling objects towards Earth's center.

Newton's First Law

An object at rest stays at rest unless acted upon.

Example of First Law

A book remains on a table until pushed.

Newton's Second Law

Force equals mass times acceleration (F=ma).

Example of Second Law

A heavier object requires more force to move.

Newton's Third Law

For every action, there is an equal opposite reaction.

Example of Third Law

Rocket propulsion pushes down, lifting the rocket up.

Friction

Force opposing the motion of an object.

Balanced Forces

No change in motion occurs when forces are equal.

Unit of Force

Newton (N) is the standard unit of force.

Energy

Capacity to do work or produce change.

Kinetic Energy

Energy of an object in motion.

Potential Energy

Stored energy due to position or condition.

Chemical Energy

Energy stored in chemical bonds of substances.

Nuclear Energy

Energy released during nuclear reactions.

Mechanical Energy

Sum of kinetic and potential energy in an object.

Thermal Energy

Energy related to the temperature of an object.

Sound Energy

Energy produced by vibrating sound waves.

Radiant Energy

Energy carried by electromagnetic waves.

Matter

Anything that has mass and occupies space.

States of Matter

Solid, liquid, and gas are the three states.

Solubility

Ability of a substance to dissolve in a solvent.

Precipitate

Solid formed from a chemical reaction in solution.

Boiling Point

Temperature at which a liquid turns to gas.

Chemical Change Signs

Bubbles, color change, heat, or light production.

Physical Change

Change affecting form but not chemical composition.

Wildfire Physical Change

Burning wood changes to ash and smoke.

Location Dependent Property

Weight varies based on gravitational pull.

Chemical Properties

Characteristics that determine how substances react.

Recognizing Physical Changes

Changes that do not alter substance identity.

Solid

Keeps its shape and volume; particles are tightly packed and only vibrate a little, making it sturdy. Example: Ice.

Liquid

Has a set volume but takes the shape of its container; particles are close together but can slide past each other, allowing it to flow. Example: Water.

Gas

Doesn't have a fixed shape or volume; particles are far apart and move freely, filling the whole space. Example: Air.

Plasma

Similar to gas, but made of charged particles; found in stars like the sun, and has special properties due to being ionized. Example: The Sun.

Melting

Solid to liquid transition, like ice turning into water, happens at the melting point. Example: Ice melting into water.

Freezing

Liquid becomes solid, as in water freezing into ice, which happens at the freezing point (same as melting point). Example: Water freezing into ice.

Boiling

Liquid to gas transition, like water turning into steam, happens at the boiling point. Example: Water boiling into steam.

Evaporation

Liquid turns into gas, like water becoming steam; this can happen at any temperature but is faster with heat. Example: Water evaporating into steam.

Condensation

Gas changes to liquid, like steam turning back into water; important for the water cycle. Example: Steam condensing into water droplets.

Sublimation

Solid directly becomes gas, like dry ice (solid CO2) turning into gas without becoming liquid. Example: Dry ice sublimating into carbon dioxide gas.

Deposition

Gas directly becomes solid without becoming a liquid first, like frost forming from water vapor. Example: Frost forming from water vapor.

Water's Anomaly

Water expands when it freezes, so ice floats, which is important for aquatic life.

Dry Ice

It's solid carbon dioxide that turns into gas at room temperature, great for creating fog in shows.

Oobleck

A weird fluid made of cornstarch and water that acts like a solid when pressed but flows like a liquid when not pressed.

Bose-Einstein Condensate

This state of matter occurs at extremely low temperatures, near absolute zero. The particles act as a single quantum entity.

Thermal Energy

The energy that comes from heat, generated by the movement of particles within a substance. The faster the particles move, the more thermal energy they have.

Solid to Liquid (Melting)

When thermal energy is added to a solid, its particles move faster and break out of their fixed positions, turning into a liquid. Example: Adding heat to ice makes it melt into water.

Liquid to Gas (Evaporation)

Adding more thermal energy to a liquid makes its particles move so fast that they break free from the liquid's surface and become a gas. Example: Heating water until it becomes steam.

Gas to Liquid (Condensation)

Removing thermal energy from a gas slows down its particles, causing them to come closer together and form a liquid. Example: Cooling steam until it becomes water droplets.

Liquid to Solid (Freezing)

Taking away thermal energy from a liquid makes its particles move slower and settle into fixed positions, becoming a solid. Example: Freezing water into ice.

Solid to Gas (Sublimation)

Adding enough thermal energy to a solid can make its particles break free completely and turn directly into a gas.

Sublimation

Adding enough thermal energy to a solid can make its particles break free completely and turn directly into a gas. Example: Dry ice sublimating into carbon dioxide gas.

Deposition

Removing thermal energy from a gas can make its particles slow down enough to form a solid without becoming a liquid first. Example: Frost forming from water vapor.

Charles's Law

Charles's Law says that when the pressure is constant, the volume of a gas increases as its temperature (in Kelvin) increases.

Boyle's Law

Boyle's Law says that when the temperature is constant, increasing pressure decreases volume.

Real-Life Example of Charles's Law

Hot air balloons rise when heated air expands, reducing density.

Real-Life Example of Boyle's Law

Syringes; pulling the plunger back lowers pressure and draws liquid in.

Solid

Ice (fixed shape and volume).

Liquid

Water (fixed volume, takes container shape).

Gas

Air (fills container, no fixed shape or volume).

Plasma

The Sun (charged particles, gas-like).

Melting

Ice to water.

Freezing

Water to ice.

Boiling

Water boiling into steam.

Evaporation

Water to steam.

Condensation

Steam to water drops.

Quick Recap of States of Matter

Solid: Ice; Liquid: Water; Gas: Air; Plasma: The Sun; Bose-Einstein Condensate: Near absolute zero.

Balloon and Cold Water Experiment

Take a balloon and inflate it slightly. Place the balloon in a bowl of ice water. Observe how the balloon shrinks as the temperature decreases.

Marshmallow in a Syringe Experiment

Place a marshmallow inside a syringe (without the needle). Pull back the plunger to decrease the pressure inside the syringe. Watch the marshmallow expand as the volume inside the syringe increases.

Three Main States of Matter

The three main states of matter are solid, liquid, and gas.

Definition of a Solid

A solid is a state of matter that has a definite shape and volume.

Solid

A solid is a state of matter that has a definite shape and volume. The particles in a solid are tightly packed and vibrate in place. Example: Ice, wood, or a rock.

Liquid

A liquid is a state of matter that has a definite volume but no definite shape. It takes the shape of its container. The particles in a liquid are close together but can move past each other. Example: Water, juice, or milk.

Gas

A gas is a state of matter that has no definite shape or volume. It expands to fill its container. The particles in a gas are far apart and move freely. Example: Oxygen, carbon dioxide, or steam.

Matter

Matter is anything that has mass and takes up space. Everything around us, including solids, liquids, and gases, is made of matter.

Physical Properties of Matter

Physical properties are characteristics that can be observed or measured without changing the substance into something else. Examples include color, texture, density, melting point, and boiling point.

Density

Density is a physical property that measures how much mass is in a given volume. It is calculated using the formula: Density = Mass ÷ Volume.

Effect of Heating on Particles

When matter is heated, the particles gain energy and move faster. This can cause a solid to melt into a liquid or a liquid to evaporate into a gas.

Physical Change

A physical change is a change in the appearance or state of matter without forming a new substance (e.g., melting ice or tearing paper).

Chemical Change

A chemical change is a change that results in the formation of a new substance (e.g., burning wood or rusting iron).

Evaporation

Evaporation is the process by which a liquid changes into a gas, usually due to heating. Example: Water evaporating from a puddle into water vapor.

Condensation

Condensation is the process by which a gas changes into a liquid, usually due to cooling. Example: Water vapor turning into dew on grass.

Freezing

Freezing is the process by which a liquid changes into a solid, usually due to cooling. Example: Water turning into ice.

Melting

Melting is the process by which a solid changes into a liquid, usually due to heating. Example: Ice melting into water.

Boiling Point of Water

The boiling point of water is 100°C (212°F) at standard atmospheric pressure.

Melting Point of Ice

The melting point of ice is 0°C (32°F).

Mixture

A mixture is a combination of two or more substances that are not chemically bonded and can be separated physically. Example: Salad, trail mix, or saltwater.

Solution

A solution is a type of mixture where one substance (the solute) is dissolved in another (the solvent). Example: Sugar dissolved in water.

Mass

Mass is the amount of matter in an object and is measured in grams or kilograms.

Weight

Weight is the force of gravity acting on an object's mass and is measured in newtons or pounds.

Volume

Volume is the amount of space an object or substance occupies. It can be measured in liters, milliliters, or cubic centimeters.

Particle Theory of Matter

The particle theory of matter states that: All matter is made up of tiny particles. These particles are always moving. There are spaces between the particles. Particles can be attracted to each other.

Kinetic Energy (KE)

Formula: KE = 1/2 × mass × velocity². Example: If a ball (mass = 2 kg) moves at 3 m/s: KE = 1/2 × 2 × 3² = 1/2 × 2 × 9 = 9 Joules.

Gravitational Potential Energy (GPE)

Formula: GPE = mass × gravity × height. (Gravity on Earth ≈ 9.8 m/s², but you can round to 10 for simplicity.) Example: A book (mass = 1 kg) on a shelf (height = 2 m): GPE = 1 × 10 × 2 = 20 Joules.

Work (Energy Transfer)

Formula: Work = Force × Distance. Example: Pushing a box with 5 Newtons of force for 3 meters: Work = 5 × 3 = 15 Joules.

Efficiency (Useful Energy vs. Total Energy)

Formula: Efficiency = (Useful Energy Out / Total Energy In) × 100%. Example: A light bulb uses 100 J but only gives 15 J of light: Efficiency = (15 / 100) × 100% = 15%.

Power (Rate of Energy Use)

Formula: Power = Energy / Time. (Units: Watts = Joules/second) Example: A device uses 60 Joules in 5 seconds: Power = 60 / 5 = 12 Watts.

Speed (Not Energy, but Related to Kinetic Energy)

Formula: Speed = Distance / Time. Example: A bike travels 30 meters in 5 seconds: Speed = 30 / 5 = 6 m/s.

First Law of Motion

An object at rest stays at rest, and an object in motion stays in motion unless acted on by a force.

Second Law of Motion

Force = mass × acceleration.