Major Concepts: Activity 31 Drinking water comes from either surface water (lakes and rivers) or groundwater accessed by springs or wells. Water may contain chemical or biological contaminants, which may have come from wastewater.

Major Concepts: Activity 32 Scientists use appropriate tools and techniques to gather, analyze, and interpret data Scientists formulate and test their explanations of natural phenomena using observations, experiments, and physical, theoretical, and mathematical models

Major Concepts: Activity 35 Water pollution can be categorized as chemical contamination or biological contamination. Major Concepts: Activity 35 Substances have characteristic properties, such as density, melting point, and boiling point, that are independent of the amount of the sample. Phase changes, such as melting and boiling, are physical changes. Substances generally exist in one or more of the three phases: solid, liquid, and gas.

Major Concepts: Activity 36 An element is a substance made up of only a single type of atom. Elements combine with each other in characteristic ways to form new substances (compounds) with different characteristic properties. Molecules are combinations of atoms held together by forces called bonds. A compound is a substance made up of atoms of more than one kind of element, bonded together to form molecules. The properties of different compounds are related to their molecular structure.

Major Concepts: Activity 37 Dissolved particles may be detected by sight as a color change of the solution; undissolved particles are always visible. A filter can remove only undissolved solid particles from a mixture. Scientists design controlled variables in investigations to obtain fair and informative comparisons.

Major Concepts: Activity 38 A solution exists when one substance, the solute (solid), dissolves in another, the solvent (liquid). A solution is clear. Solubility, the amount of a substance that can dissolve in a particular solvent, such as water or ethanol, varies from substance to substance. A solution reaches saturation when no more of the solute can dissolve. Water can dissolve many different solutes and is often called the universal solvent.

Major Concepts: Activity 39 Water circulates through the earth’s crust, oceans, and atmosphere in the water cycle. It evaporates from the surface, rises, cools at higher evaluations, condenses as rain or snow, and falls to the surface where it collects in lakes, oceans, soil, and rock layers underground.

Activity 39 Analysis 2. Explain why the water lost contaminants when it moved into the atmosphere. The contaminants do not evaporate and are left behind when the water evaporates into the atmosphere At what points in the water cycle did the water molecules not pick up any contaminants? No contaminants go into the atmosphere Get left behind when water evaporates Very few contaminants are picked up in the atmosphere It didn’t pick up contaminants from organisms because the parts of the organism listed do not produce significant water contaminants—only waste does Sometimes the die roll stated no contaminants were picked up, because contaminants aren’t always present or there aren’t enough of them to pick up

The term “water cycle” describes the movement of water on earth and in the earth’s atmosphere. Do you think that your diagram is a good summary of the water cycle? Why or why not? The diagram shows most parts of the water cycle, but does not clearly represent a cycle that repeats.

Expand you notes from “My Water Cycle Story,” into a story that describes the journey of your water molecules. You story should follow your water through at least five places. Be as creative and scientifically accurate as you can be. Be sure to: Describe or draw how your water molecules moved from one place to another. Identify any changes in state (solid, liquid, gas) that occur. Describe any contaminants the water picks up as it travels and how the contaminants got there.

There was a freezing rainstorm in our town There was a freezing rainstorm in our town. One water molecule formed icicles with other molecules on the door of a car. As the water molecules sat on the car, they picked up detergent that had been used to wash the car. When the hailstorm stopped, the molecules melted with the rest of the icicle onto the pavement. As they flowed with the melted water down the gutter, they picked up oil that had leaked onto the pavement from vehicles. The water traveled down the gutter until it reached a storm sewer that led to the ocean. The ocean water had been contaminated with oil from a major spill from a barge, so the molecules picked up more oil when they entered the ocean.

The ocean water molecules evaporated into water vapor, leaving the detergent and oil behind. Some time later, they condensed and precipitated as pure rain molecules and rained down into a lake. The lake was next to a copper-processing plant, so copper waste was picked up by the pure molecules. A horse drank from the lake and started to sweat. The water molecules were part of the liquid sweat on the horse’s skin. The horse’s sweat didn’t contain contamination, but the copper could make the horse sick if there was enough of it in the lake. Eventually, the molecules evaporated from the horse’s skin as it grazed in the sunlight. When the molecules became pure precipitation once again, they were part of snow that fell on a river in the mountains. The river contained bacteria from the animal waste of animals living nearby, such as beavers. The water molecules ran with the river down to a lake where they picked up more bacteria that ran into the lake from the cows on a dairy farm near the lake.

Make up a Progressive Story We will start with the precipitation card As the number cube is rolled and we move to the next location, each student must add to the story one sentence at a time Include information about where the molecule goes what kind of contaminants it picks up and where it leaves them