Chemistry

Draw a solid, a liquid and a gas and describe each in a simple sentence. 

Play this physical properties game: Hide an object inside a paper bag. Make a list of physical properties that apply to that object and then read the list aloud to the class. Have students use their critical thinking skills and knowledge of physical properties to ask questions as they try to identify the object. 

Place 3D objects inside a box. Allow students to tilt, shake and listen to the contents. From their “observations” of approximate weight, size, shape, and other physical properties, determine how many objects are in the box and what shape they have. Write a paragraph describing the object(s). Open the box and compare the objects to the students' written assessments. Discuss how scientists often make determinations about atoms and their sub-particles based on experiments that involve things they cannot actually observe. Share this Q&A on How do we really know atoms exist after doing this activity.

Using paper versions of thermometers, fill in the thermometers to identify freezing and boiling points on both a Fahrenheit and Celsius scale. Determine the interval between freezing and boiling points. Practice reading temperatures and temperature changes. You may wish to use these thermometer worksheets. 

In a glass container, mix ¼ cup vinegar with 1 tablespoon of baking soda. Measure how long the reaction lasts. When it has stopped creating foam, add an antacid tablet (such as Rolaids or Tums.) Measure with a stopwatch to see how long the mixture takes to deplete the bubbles.

Measure and calculate the density of several solids and liquids using the formula "density equals mass divided by volume." You may wish to use these activity instructions.  

Using Jefferson Lab's Balancing Act activity, balance chemical equations so that both sides have equivalent numbers of given atoms. Use the distributive property to determine the correct coefficients for molecules.

Different kinds of matter exist and many of them can be solid, liquid, or gas, depending on temperature. Matter can be described and classified by its observable properties. Observations could include color, texture, hardness, and flexibility. Patterns could include the similar properties that different materials share.

A great variety of objects can be built up from a small set of pieces. Examples of pieces could include blocks, building bricks, or other assorted small objects.

Heating or cooling a substance may cause changes that can be observed. Sometimes these changes are reversible, and sometimes they are not.  Examples of reversible changes could include materials such as water and butter at different temperatures. Examples of irreversible changes could include cooking an egg, freezing a plant leaf, and heating paper.

Matter of any type can be subdivided into particles that are too small to see, but even then, the matter still exists and can be detected by other means. A model showing that gases are made from matter particles that are too small to see and are moving freely around in space can explain many observations, including the inflation and shape of a balloon and the effects of air on larger particles or objects.  Examples of evidence supporting a model could include adding air to expand a basketball, compressing air in a syringe, dissolving sugar in water, and evaporating salt water.

The amount (weight) of matter is conserved when it changes form, even in transitions in which it seems to vanish. No matter what reaction or change in properties occurs, the total weight of the substances does not change. Examples of reactions or changes could include phase changes, dissolving, and mixing that form new substances.

Measurements of a variety of properties can be used to identify materials. Examples of materials to be identified could include baking soda and other powders, metals, minerals, and liquids. Examples of properties could include color, hardness, reflectivity, electrical conductivity, thermal conductivity, response to magnetic forces, and solubility.

When two or more different substances are mixed, a new substance with different properties may be formed. 

Substances are made from different types of atoms, which combine with one another in various ways. Atoms form molecules that range in size from two to thousands of atoms.  Solids may be formed from molecules, or they may be extended structures with repeating subunits (e.g., crystals.) Emphasis is on developing models of molecules that vary in complexity. Examples of simple molecules could include ammonia and methanol. Examples of models could include drawings, 3D ball and stick structures, or computer representations.

Each pure substance has characteristic physical and chemical properties (for any bulk quantity under given conditions) that can be used to identify it. Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants.  Examples of reactions could include burning sugar or steel wool, fat reacting with sodium hydroxide, and mixing zinc with hydrogen chloride. Assessment may include analysis of the following properties: density, melting point, boiling point, solubility, flammability, and odor.

Substances react chemically in characteristic ways. In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants. Emphasis is on natural resources that undergo a chemical process to form the synthetic material. Examples of new materials could include new medicine, foods, plastics, and alternative fuels.

Gases and liquids are made of molecules or inert atoms that are moving about relative to each other. In a liquid, the molecules are constantly in contact with others; in a gas, they are widely spaced except when they happen to collide. In a solid, atoms are closely spaced and may vibrate in position but do not change relative locations. The changes of state that occur with variations in temperature or pressure can be described and predicted using these models of matter.  Emphasis is on qualitative molecular-level models of solids, liquids, and gases to show that adding or removing thermal energy increases or decreases kinetic energy of the particles until a change of state occurs. Examples of models could include drawings and diagrams. Examples of particles could include molecules or inert atoms. Examples of pure substances could include water, carbon dioxide, and helium.

In a chemical process, the atoms that make up the original substances are regrouped into different molecules, and these new substances have different properties from those of the reactants. The total number of each type of atom is conserved, and thus the mass does not change. Emphasis is on law of conservation of matter and on physical models or drawings, including digital forms, that represent atoms.

Some chemical reactions release energy, others store energy. Examples of designs could involve chemical reactions such as dissolving ammonium chloride or calcium chloride. Emphasis is on the design, controlling the transfer of energy to the environment, and modification of a device using factors such as type and concentration of a substance.  A solution needs to be tested and then modified on the basis of the test results in order to improve it. The iterative process of testing the most promising solutions and modifying what is proposed on the basis of the test results leads to greater refinement and ultimately to an optimal solution.

Within individual organisms, food moves through a series of chemical reactions in which it is broken down and rearranged to form new molecules, to support growth, or to release energy. Emphasis is on describing that molecules are broken apart and put back together and that in this process, energy is released, and on understanding that the elements in the products are the same as the elements in the reactants.