Topic-+Atoms,+Molecules+and+States+of+Matter

Topic: Atoms, Molecules, and States of Matter
Below is a list of key ideas related to Atoms, Molecules, and States of Matter. For each key idea, you will find a list of sub-ideas, a list of items, results from our field testing, and a list of student misconceptions. After clicking on a tab, click on it again to close the tab.

All matter is made up of atoms.
//Students are expected to know that:// //Boundaries://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) Matter is anything that has mass and takes up space.
 * 2) Matter includes all gases, liquids, and solids, which make up all living and non-living things.
 * 3) Light, heat, and electricity are not matter.
 * 4) All matter—solids, liquids, and gases—is made up of discrete particles (atoms), rather than being continuous, and that these atoms //are the matter// rather than //contained in matter//. In other words, the atoms are not floating or embedded in some other substance, such as air or a liquid.
 * 5) Matter can exist even when it cannot be seen. For example, gases or vapors are matter even though some of them cannot be seen.
 * 6) Anything made up of atoms is matter.
 * 7) It is because atoms take up space and have mass that all matter takes up space and has mass.
 * 1) It is not expected that students will know ideas about the internal structure of atoms or the existence of subatomic particles.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|AM059002] || [|Matter is made up of atoms.] || 64% || 72% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1002"]] ||
 * [|AM024005] || [|If you remove all of the atoms from a chair, nothing will remain.] || 57% || 73% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1004"]] ||
 * [|AM023005] || [|Air is matter because it is made up of atoms.] || 57% || 71% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1316"]] ||
 * [|AM058001] || [|A gas, a solid, and a cell are all made up of atoms but heat is not.] || 53% || 66% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/750"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.
 * ~ Student Misconception ||~ Grades
 * [|AMM070] || [|Cells are not made up of atoms (Herrmann-Abell & DeBoer, 2008).] || 27% || 20% ||
 * [|AMM107] || [|Air does not take up space (Driver et al., 1994).] || 22% || 16% ||
 * [|AMM009] || [|Atoms or molecules are embedded in matter (Renstrom et al., 1990; Griffiths et al., 1992; Lee et al., 1993; Johnson, 1998c).] || 18% || 13% ||
 * [|AMM020] || [|Solids are not made up of atoms; especially those without visible granularity (Johnson, 1998c; Nakhleh et al., 1999; Nakhleh et al., 2005; Nakhleh et al., 2006).] || 10% || 7% ||
 * [|AMM022] || [|Matter exists only when there is perceptual evidence of its existence (Stavy, 1990).] || 10% || 7% ||
 * [|AMM137] || [|Gases are not made up of atoms (AAAS Project 2061, n.d.).] || 10% || 7% ||
 * [|AMM031] || [|Biological materials are not matter (Stavy, 1991).] || 9% || 6% ||

All atoms are extremely small.
//Students are expected to know that:// //Boundaries://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) Individual atoms are much smaller than things that can be seen and even much smaller than very small things, such as dust, germs and other microorganisms, blood cells, and plant cells.
 * 2) This is true for all atoms.
 * 3) All atoms are so small that billions of them make up these small things.
 * 1) The comparison with very small objects can be used to test students’ understanding of the relative size of atoms in relation to these objects. Students will not, however, be expected to know the actual size of atoms.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|AM025002] || [|A grain of sand is bigger than an atom.] || 65% || 78% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1013"]] ||
 * [|AM060003] || [|An atom is smaller than the width of a hair, a cell in your body, and a germ.] || 63% || 77% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1010"]] ||
 * [|AM026001] || [|A blood cell is bigger than an atom.] || 63% || 76% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/581"]] ||
 * [|AM061003] || [|It would take millions of atoms to make a line across a small dot (about one millimeter in diameter).] || 38% || 56% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1011"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.
 * ~ Student Misconception ||~ Grades
 * [|AMM124] || [|A germ is smaller than an atom (AAAS Project 2061, n.d.).] || 17% || 9% ||
 * [|AMM068] || [|Cells are smaller than atoms (Tretter et al., 2006).] || 12% || 7% ||
 * [|AMM125] || [|A grain of sand is smaller than an atom (AAAS Project 2061, n.d.).] || 12% || 8% ||
 * [|AMM001] || [|Atoms/molecules are similar in size to cells, dust, or germs/bacteria (Lee et al., 1993; Nakhleh et al., 1999).] || 9% || 8% ||
 * [|AMM104] || [|The width of a hair is smaller than an atom (Tretter et al., 2006).] || 8% || 6% ||

All atoms and molecules are in constant motion.
//Students are expected to know that:// //Boundaries://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) Atoms and molecules of //all// matter are //always// moving.
 * 2) This is true for atoms or molecules of solids, liquids, and gases.
 * 3) Even when objects that are made up of these atoms and molecules appear not to be moving, the atoms and molecules that make up those objects are nonetheless themselves in constant motion.
 * 4) The motion of atoms or molecules can include moving back and forth with respect to a fixed point, around a fixed point, and/or past each other from one fixed point to another.
 * 5) The motion (speed and direction) of an atom or molecule can change when it undergoes collision with another atom or molecule resulting in one speeding up and the other slowing down.
 * 6) Because atoms and molecules are continually colliding with each other, the atoms/molecules of the substance do not have the same speed.
 * 1) Students are not expected to know the terms rotation, translation, and vibration.
 * 2) They are also not expected to know that atoms and molecules of different substances move at different speeds at the same temperature.
 * 3) Students are not expected to know the special case of absolute zero temperature where, according to kinetic theory, there should be no motion.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|AM066003] || [|The molecules of the glass that makes up a window are always moving.] || 36% || 52% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1026"]] ||
 * [|AM053006] || [|The atoms and molecules of both a chair and air in a balloon are moving.] || 37% || 43% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1317"]] ||
 * [|AM054004] || [|The molecules of liquid water in a cup would not stop moving even if the water became a solid, a gas, or if the liquid became still.] || 34% || 44% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1319"]] ||
 * [|AM063002] || [|The water molecules in a glass of liquid water are moving at different speeds.] || 37% || 36% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1057"]] ||
 * [|AM053007] || [|The atoms and molecules of both liquid water and a table are moving.] || 30% || 44% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1318"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.
 * ~ Student Misconception ||~ Grades
 * [|AMM032] || [|Atoms or molecules of a solid are not moving (Lee et al., 1993; Novak & Musonda, 1991).] || 48% || 42% ||
 * [|AMM058] || [|Molecules within a phase move at the same speed (Griffiths et al., 1992).] || 41% || 47% ||
 * [|AMM054] || [|The atoms or molecules of a liquid will stop moving when the liquid becomes a solid (Novak & Musonda, 1991).] || 42% || 35% ||
 * [|AMM127] || [|The atoms or molecules of a solid move only when heated. For example, the molecules of a glass window move only when the window is warmed by the sun (AAAS Project 2061, n.d.).] || 24% || 19% ||
 * [|AMM033] || [|Atoms or molecules of a liquid are not moving when the liquid itself is still (Johnson, 1998c).] || 22% || 16% ||
 * [|AMM034] || [|Atoms or molecules of a gas are not in motion (Novick et al., 1981).] || 16% || 15% ||
 * [|AMM078] || [|The atoms and molecules of a solid object move only when the object itself moves or is moved (AAAS Pilot testing, 2006).] || 10% || 6% ||

There are differences in the spacing, motion, and interaction of atoms and molecules that make up solids, liquids, and gases.
//Students are expected to know that:// //Boundaries://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) The particles of a gas (atoms or molecules) are much farther apart than the atoms or molecules of a liquid or a solid. Because atoms or molecules of a gas are so far apart they rarely come in contact with each other. In solids and liquids, the atoms or molecules are packed closely together.
 * 2) Although the motion of atoms or molecules of a solid is severely restricted, the atoms or molecules are constantly moving back and forth in all directions with respect to a fixed position. In liquids, the motion of the atoms or molecules is limited but the atoms or molecules can still move rapidly back and forth with respect to a fixed point, around a fixed point, and past each other from one fixed point to another. Atoms or molecules of a gas move freely and spread out throughout the container they occupy.
 * 3) Similar to the pushes and pulls between magnets, atoms or molecules also push and pull on each other.
 * 4) In solids, the atoms or molecules pull strongly on each other and are linked together in rigid structures.
 * 5) In liquids, the atoms or molecules pull less strongly on each other, are more loosely connected, and form less rigid structures.
 * 6) In gases, the pull between atoms or molecules is so weak that they do not form structures.
 * 7) Hardness, flow, and compressibility are macroscopic properties for which students are expected to know the molecular reason.
 * 8) Solids are hard because the atoms or molecules are linked together tightly in rigid structures, not because the individual atoms or molecules are hard.
 * 9) The atoms or molecules of liquids can easily move past each other from one fixed point to another but do not move apart from one another and that this is why liquids flow and take the shape of their container but solids do not.
 * 10) Gases can be compressed because the atoms or molecules are not as close together as they could be, not because the individual atoms or molecules are soft.
 * 1) Students are not expected to know the nature of the bonds between atoms or between molecules.
 * 2) They are not expected to know that atoms or molecules of a solid can sometimes move past each other.
 * 3) Students are not expected to know the terms rotation, translation, and vibration.
 * 4) They are not expected to know that plasma is a distinct state of matter, and they are not expected to know the properties of a plasma.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|AM027003] || [|Molecules are spaced farthest apart in a gas.] || 66% || 76% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1035"]] ||
 * [|AM056003] || [|The molecules of a gas are far apart from one another.] || 61% || 69% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1038"]] ||
 * [|AM055002] || [|The connection between the molecules of a solid are the strongest compared to the molecules of a liquid or a gas.] || 61% || 71% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1037"]] ||
 * [|AM033003] || [|Ice is harder than liquid water because the molecules of ice are linked more tightly together than the molecules of liquid water.] || 50% || 66% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1036"]] ||
 * [|AM069002] || [|The molecules of a gas are spread far apart throughout a sealed container.] || 47% || 62% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1040"]] ||
 * [|AM068003] || [|Gases can be compressed more easily than solids because the molecules of gases are farther apart than the molecules of solids.] || 39% || 55% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1039"]] ||
 * [|AM057005] || [|Liquid water takes the shape of a cup it is poured into but solid ice cubes do not, because the molecules of liquid water can easily move past one another but the molecules of solid ice cannot.] || 39% || 48% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1327"]] ||
 * [|AM071002] || [|Liquid candle wax flows but solid candle wax does not because the molecules of liquid candle wax can easily move past one another but the molecules of solid candle wax cannot.] || 35% || 53% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1042"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.
 * ~ Student Misconception ||~ Grades
 * [|AMM032] || [|Atoms or molecules of a solid are not moving (Lee et al., 1993; Novak & Musonda, 1991).] || 32% || 30% ||
 * [|AMM118] || [|Particles of a gas are closely packed with no empty space between them (Benson et al., 1993; Novick & Nussbaum, 1978).] || 32% || 20% ||
 * [|AMM017] || [|Atoms and molecules of a gas in a container are not uniformly distributed (Novick et al., 1981; Lee et al., 1993).] || 21% || 18% ||
 * [|AMM016] || [|The gas state of a substance weighs less than the liquid or solid state (Stavy, 1990).] || 17% || 15% ||
 * [|AMM015] || [|Observable properties of the state are attributed to the individual molecules (e.g., molecules in a solid are hard; molecules move in gases and liquids, but not in solids; or the molecules of the substance change from soft to hard when a liquid freezes) (Lee et al., 1993).] || 18% || 10% ||
 * [|AMM128] || [|The molecules of the gas state are the lightest and the molecules of the solid state are the heaviest (Griffiths et al., 1992).] || 15% || 9% ||
 * [|AMM034] || [|Atoms or molecules of a gas are not in motion (Novick et al., 1981).] || 8% || 8% ||

For any single state of matter, increasing the temperature typically increases the distance between atoms or molecules. Therefore, most substances expand when heated.
//Students are expected to know that:// //Boundaries://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) As the temperature of a substance increases, the average distance between the atoms/molecules of the substance typically increases, causing the substance to expand.
 * 2) As the temperature of a substance decreases, the average distance between the atoms/molecules typically decreases, causing the substance to contract.
 * 3) This expansion or contraction can happen to solids, liquids, and gases.
 * 4) Expansion or contraction due to changes in temperature can also happen to mixtures of substances.
 * 5) Expansion or contraction due to changes in temperature is not permanent (e.g., objects that expand when heated then contract when cooled).
 * 6) The number of atoms and the mass of the atoms do not change with changes in temperature.
 * 7) Different substances expand and contract differently.
 * 1) Students are not expected to know the details of the relationship between the speed of the atoms or molecules and thermal expansion.
 * 2) They are also not expected to know the substances that violate this rule and shrink when heated or that water will shrink when heated anywhere between 0°C and 4°C.
 * 3) Students are not expected to know or apply gas law equations.
 * 4) Because the definition of the size of an atom is varied and complex, we only expect students to know that the size of an atom or molecule does not decrease when the temperature increases and that the size does not increase when temperature decreases.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|AM051005] || [|When a sealed plastic bottle filled with air is placed in the refrigerator, the bottle becomees dented because molecules of air inside the bottle get closer together.] || 50% || 65% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1326"]] ||
 * [|AM073002] || [|The molecules of hot air are farther apart than the molecules of cold air.] || 49% || 60% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1030"]] ||
 * [|AM045004] || [|The molecules of cold water are closer together than the molecules of hot water.] || 46% || 59% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1028"]] ||
 * [|AM052005] || [|When an iron frying pan cools, the distance between the iron atoms decreases.] || 45% || 59% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1016"]] ||
 * [|AM049003] || [|The distance between water molecules increases when a cup of cold water warms up to room temperature.] || 39% || 59% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1019"]] ||
 * [|AM039004] || [|The distance between water molecules increases as a cup of water is warmed.] || 38% || 58% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1018"]] ||
 * [|AM042005] || [|When a glass thermometer is placed in hot water, the level of liquid rises because the molecules get farther apart.] || 39% || 58% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1021"]] ||
 * [|AM052004] || [|When an iron frying pan heats up, the distance between the iron atoms increases, so the pan gets a tiny bit larger.] || 30% || 43% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1015"]] ||
 * [|AM046006] || [|During a hot day in the summer, the spaces between the concrete sections of a sidewalk get narrower because the concrete sections expand.] || 27% || 47% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1325"]] ||
 * [|AM052003] || [|When an iron frying pan cools, the distance between the iron atoms decreases, so the pan gets a tiny bit smaller.] || 26% || 33% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1014"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.
 * ~ Student Misconception ||~ Grades
 * [|AMM089] || [|Solid substances do not expand or contract with changes in temperature (Herrmann-Abell & DeBoer, 2007, 2008).] || 34% || 25% ||
 * [|AMM096] || [|The mass of the atoms or molecules of a substance increases when the temperature increases and decreases when the temperature decreases (AAAS Project 2061, n.d.).] || 25% || 22% ||
 * [|AMM122] || [|The average distance between the atoms or molecules of a substance remains the same when the temperature of the substance changes (AAAS Project 2061, n.d.).] || 25% || 18% ||
 * [|AMM038] || [|Heat is made of "heat molecules" (Berkheimer et al., 1988).] || 24% || 16% ||
 * [|AMM086] || [|The number of atoms or molecules of a substance increases when the temperature increases and decreases when the temperature decreases (Herrmann-Abell & DeBoer, 2008).] || 21% || 13% ||
 * [|AMM019] || [|Water molecules break down when heated (Griffiths et al., 1992).] || 19% || 14% ||
 * [|AMM091] || [|The mass of the atoms or molecules of a substance increases when the temperature decreases and decreases when the temperature increases (Herrmann-Abell & DeBoer, 2007, 2008).] || 19% || 15% ||
 * [|AMM129] || [|The molecules of air break down when the air is cooled (AAAS Project 2061, n.d.).] || 19% || 12% ||
 * [|AMM037] || [|Substances shrink when heated (especially solids) (Lee et al., 1993).] || 15% || 12% ||
 * [|AMM087] || [|The number of atoms or molecules of a substance increases when the temperature decreases and decreases when the temperature increases (Herrmann-Abell & DeBoer, 2007).] || 16% || 9% ||
 * [|AMM076] || [|The size of the atoms or molecules of a substance increases when the temperature decreases and decreases when the temperature increases (AAAS Project 2061, n.d.).] || 14% || 11% ||

==== When heated, solids can change into liquids and liquids can change into gases. When cooled, gases can change into liquids and liquids can change into solids. These changes of state can be explained in terms of changes in the proximity, motion, and interaction of atoms and molecules. ==== //Students are expected to know that:// //Boundaries://
 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]
 * 1) When the temperature of a liquid decreases, the average speed of the atoms or molecules decreases and, as a result, the pull that exists between the atoms or molecules is strong enough to link them together as a solid.
 * 2) When the temperature of a solid increases, the average speed of the atoms or molecules increases and the pull between the atoms or molecules is no longer strong enough to hold them together as a solid; the atoms or molecules are now more loosely connected as a liquid.
 * 3) When the temperature of a gas decreases, the average speed of the atoms or molecules decreases and, as a result, the pull that exists between the atoms or molecules is strong enough to loosely connect them together as a liquid.
 * 4) When the temperature of a liquid increases, the average speed of the atoms or molecules increases and the pull between the atoms or molecules is no longer strong enough to hold them together as a liquid. In this case, the pull between atoms or molecules is so weak that they are no longer connected to each other, but rather they exist as a gas.
 * 5) At the boiling point and freezing point, atoms or molecules from anywhere in the substance can enter the gas state and solid state, respectively. Because of this, the bubbles that form when the substance is boiling are atoms or molecules of that substance in the gaseous state.
 * 6) Evaporation or condensation can also occur independent of temperature; i.e., at any temperature there are some atoms or molecules that may move from one state to another at the surface of a substance. This also includes atoms or molecules on the surface of a solid that can enter the gas state.
 * 7) A substance is made up of the same type of atom or molecule regardless of whether it is in the solid, liquid, or gas state. There is //no// change in the identity of the atoms or molecules during a change of state; only the arrangement, motion, and interaction of the atoms or molecules change.
 * 8) Atoms or molecules are not destroyed during a change of state.
 * 9) Any change of state is reversible.
 * 1) Although changes of state can be caused by changes in either temperature or pressure, students are only expected to know the effects of changes in temperature.

Percent of students answering correctly (click on the item ID number to view the item and additional data)||~ Item ID Number ||~ Knowledge Being Assessed 6–8 ||~ Grades 9–12 ||~ Select This Item for My Item Bank ||
 * ~ Grades
 * [|AM035004] || [|When a piece of solid wax is heated, it becomes a liquid and the wax molecules become more loosely connected to each other.] || 48% || 65% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1052"]] ||
 * [|AM028003] || [|When a substance changes from a liquid to a solid, the molecules of the substance connect more strongly to one another.] || 44% || 60% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1050"]] ||
 * [|AM036003] || [|Water spilled on the floor will eventually disappear because the water molecules become a gas and are now part of the air.] || 46% || 53% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1055"]] ||
 * [|AM062004] || [|As water boils, the molecules become separated from each other.] || 38% || 50% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1053"]] ||
 * [|AM065003] || [|Wet jeans hung on a clothesline eventually dry because the water molecules move faster and become part of the air.] || 38% || 47% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1056"]] ||
 * [|AM067006] || [|As a substance changes state, the connection between molecules of the substance changes.] || 37% || 48% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1328"]] ||
 * [|AM031004] || [|The bubbles that form when water boils are made of water molecules.] || 13% || 18% || [[image:http://assessment.aaas.org/img/star_16x16_grey.png link="http://assessment.aaas.org/users/itembank/add/1051"]] ||

Frequency of selecting a misconception||~ Misconception ID Number 6–8 ||~ Grades 9–12 || Frequency of selecting a misconception was calculated by dividing the total number of times a misconception was chosen by the number of times it could have been chosen, averaged over the number of students answering the questions within this particular idea.
 * ~ Student Misconception ||~ Grades
 * [|AMM061] || [|The molecules of a substance break down into individual atoms when the substance evaporates. During evaporation, water breaks down into hydrogen and oxygen (Bar et al., 1991; Bar et al., 1994).] || 39% || 37% ||
 * [|AMM049] || [|The molecules of a substance break down into individual atoms when the substance boils. For example, molecules of water become atoms of hydrogen and oxygen when water boils (Osborne et al., 1983; Renstrom et al., 1990).] || 36% || 34% ||
 * [|AMM051] || [|When water boils, the bubbles formed during boiling contain air, not water in the gas state (Osborne et al., 1983; Renstrom et al., 1990; Bar et al., 1991; Johnson, 1998a; Chang, 1999).] || 29% || 26% ||
 * [|AMM038] || [|Heat is made of "heat molecules" (Berkheimer et al., 1988).] || 25% || 17% ||
 * [|AMM043] || [|Molecules change shape during a phase change (Novak et al., 1991; Griffiths et al., 1992).] || 19% || 19% ||
 * [|AMM015] || [|Observable properties of the state are attributed to the individual molecules (e.g., molecules in a solid are hard; molecules move in gases and liquids, but not in solids; or the molecules of the substance change from soft to hard when a liquid freezes) (Lee et al., 1993).] || 23% || 12% ||
 * [|AMM047] || [|The identity of the molecules of a substance changes during a phase change (Lee et al., 1993).] || 21% || 14% ||
 * [|AMM045] || [|Molecules change weight/mass during a phase change (Griffiths et al., 1992).] || 19% || 14% ||
 * [|AMM133] || [|Matter is destroyed during melting (AAAS Project 2061, n.d.).] || 15% || 10% ||
 * [|AMM044] || [|Molecules change size during a phase change (Novak et al., 1991; Griffiths et al., 1992).] || 11% || 9% ||
 * [|AMM132] || [|Matter is destroyed during boiling (AAAS Project 2061, n.d.).] || 11% || 7% ||
 * [|AMM131] || [|Matter is destroyed during evaporation (Bar & Galili, 1994; Bar & Travis, 1991; Lee et al., 1993; Osborne & Cosgrove, 1983)] || 11% || 7% ||
 * [|AMM063] || [|When water evaporates from an object, that water is absorbed into the object (Osborne et al., 1983; Bar et al., 1991; Bar et al., 1994).] || 7% || 7% ||

For any single state of matter, the average speed of the atoms or molecules increases as the temperature of a substance increases and decreases as the temperature of a substance decreases.

 * [|Sub-Ideas]
 * [|Items & Student Performance]
 * [|Misconceptions]