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Stream Team Academy Fact Sheet #29

The Properties of

Stream Team Academy Fact Sheet Series #1 Tree Planting Guide An Educational Series For Stream Teams To Learn and Collect #2 Spotlight on Big Muddy #3 Lewis & Clark By Chris Riggert, Stream Team Program Coordinator #4 Missouri Is Number One? #5 Responsible ATV Use 90% of body weight of some organisms. #6 Headwater Streams Humans are about 60% water. #7 Whatology? H O #8 Exotic Does Not Mean Beauty 2 #9 Wetlands ne and two How much water are we? #10 Stream Sedimentation . It seems like such a simple S Lungs: about 83% #11 Emerald Ash Borer equation. But, this “simple” S Kidneys: about 79% #12 Protecting Prairies & Streams O compound and its to some S Brain and heart: about 73% #13 Aquatic Insects (Part 1) complex and interesting properties and S Skin: about 64% #14 Aquatic Insects (Part 2) interactions, some of which are what make S Bones: about 31% #15 Aquatic Insects (Part 3) life on this planet possible. #16 Aquatic Insects (Part 4) is sometimes referred to as the #17 Aquatic Insects (Part 5) ydrogen are positively charged water planet because about 70% of its #18 Aquatic Insects (Part 6) H(+) and are attracted to the negatively #19 Aquatic Insects (Part 7) surface is covered with water. Nearly all charged (-) oxygen . They attach at #20 Aquatic Insects (Part 8) of it is contained in our , with only a 105° angle through covalent bonds. #21 Freshwater Mussels about 3% of earth’s water as freshwater, This molecular structure gives the water #22 The Crayfishes and most of that is frozen in and polarity, or a lopsided electrical #23 Where Does the Rain Go? polar caps. Life as we know it would charge that attracts other atoms. The end #24 Rain Gardens not be possible without water. It is the of the molecule with the two hydrogen #25 Native Plants only natural substance which can be found #26 Invasive Species: Hydrilla atoms is positively charged and the end as a , , and at #27 Invasive Species: Didymo with the oxygen is negatively charged. normally found on Earth. This creates #28 Invasive Species: Honeysuckle This positive/negative charge makes the #29 The many opportunities for life to flourish. molecule “sticky” and is held together Water is part of every living organism through hydrogen bonds. It is these on the planet. In fact, water makes up to hydrogen bonds that make water Collect this entire educational series for future reference! Contact us at 1-800-781- so cohesive and water so special. In fact, 1989 if you’d like copies of previous Fact water is the most cohesive non-metallic Sheets and a binder for storing them. liquid. Water’s hydrogen bonds create tugging forces between water molecules, resulting in a high , allowing water molecules to clump together in drops. If you look closely at a water droplet, it appears to be coated in plastic. If you were to pour a small amount onto a flat surface, a small mound forms, preventing it from simply running off the edge. This surface tension forms a thin film where organisms such as water striders can Polarized hydrogen bonds between water “walk” across the water. However, it is this molecules attract water molecules to each other, forming the strongest cohesive non- metal liquid compound on Earth. (continued on back) Stream Team Academy Fact Sheet #29 same surface tension many benthic insects they warm because molecules move must overcome when hatching into an further apart, and become denser when adult. they cool as molecules come closer Surface tension also allows water to together. Water does get denser as its move upwards against the pull of gravity decreases. However, it is the through capillary action. Water’s high densest at 4° C and then begins to expand, surface tension also allows water to be with maximum number of hydrogen held by soil particles, providing a medium bonds forming a lattice as it for plants to obtain nutrients. Water’s freezes with molecules which are further adhesive properties are responsible for apart. This allows frozen water (0° C) to capillary action, allowing water and float on the slightly warmer water below dissolved substances to be absorbed into it. This is very important to aquatic life. If porous materials and move through roots ice were denser than liquid water it would of plants and through tiny blood vessels in sink and eventually freeze solid. However, our bodies. by floating, ice creates an insulating layer, preventing the water below from freezing ater’s many hydrogen bonds give it and allowing the living things underneath a high Specific Index, or the W to survive the winter. amount heat per unit required to raise Because water can exist as a vapor, the temperature by one degree . it can be stored in the atmosphere and It takes a lot of to break water’s delivered as rain across the planet. hydrogen bonds. This means it can absorb The next time you take a sip of water, a lot of heat before it gets hot, making it paddle a canoe across the surface, listen to an excellent . Because our planet the rain, or watch the , think of these is mostly water, oceans help regulate the properties and their importance to life on rate at which air temperatures change and the “water planet.” is the reason why seasonal temperature changes are gradual rather than sudden. This gradual change in temperatures Physical States of Water allows organisms to survive by adjusting S Freezing point at sea level: 32° F gradually themselves. It also helps regulate S at sea level: 212° F the earth’s overall temperatures as well as S Boiling point at 14,000 feet: 186.4° F influences weather patterns. S Water is considered the “universal Freezing and boiling points are baselines ” because it dissolves more with which temperature is measured substances than any other liquid. Its adhesive properties allow it to pick up valuable chemicals, minerals, nutrients, and waste as water moves through the ground or through our bodies. From a biological standpoint, water brings food into and carries waste away from cells. Water also absorbs heat when it evaporates; allowing humans to regulate body temperatures by releasing water through our skin pores, which then evaporates, cooling us off. One additional interesting property of water deals with its at different A water strider is able to “skate” across water due temperatures, or mass per unit volume. to high surface tension formed by the strong bonds Most compounds become less dense as between water molecules.

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