Amazing Water: Water and its properties

Facts About Water ▪ Water is unique because it is the only natural substance that is found in all three physical states— liquid, solid, and gas—at normal Earth temperatures. ▪ Water freezes at 0° Celsius (C) [32° Fahrenheit (F)] and boils at 100° Celsius (C) [212° Fahrenheit (F)]. ▪ The existence of water is essential for life on Earth. ▪ Water covers about 70% of the earth.

Properties of Water ▪ cohesion ▪ surface tension ▪ adhesion ▪ polarity ▪ buoyancy ▪ acts as a universal solvent ▪ has a high specific heat ▪ density ▪ capillary action

Cohesion, Surface Tension, and Adhesion ▪ Cohesion refers to the fact that water sticks to itself very easily. ▪ Surface tension allows the surface of water to "stick together" to form a type of 'skin' on the water, strong enough to support very light objects. ▪ Adhesion means that water also sticks very well to other things. ▪ Refer to ISN pg. 6 for additional information.

Polarity ▪ A molecule that has both a positively charged and a negatively charged end. ▪ A water molecule consists of 3 atoms: 1 oxygen atom and two hydrogen atoms. ▪ There is a slight negative charge at the oxygen end and a slight positive charge at the hydrogen end. ▪ Opposite poles of the H 2 O molecule make it attract other water molecules and stick together through hydrogen bonds ▪ The is the property that gives water all its other properties.

Density ▪ Density is a measure of the mass of an object compared to how much space it takes up. ▪ Water has a density of 1 g/mL (1 gram per milliliter) ▪ Density changes with temperature; cold water is denser than warm water. ▪ Density changes with a change in physical state – Water expands at is freezes and becomes less dense (this is very rare) – Ice will float in water because it is less dense than water

Buoyancy ▪ Buoyancy is the ability of a fluid to exert an upward force on an object ▪ Buoyancy is the ability for an object to float ▪ If the buoyant force acting on an object is greater than the force of gravity, then the object will float ▪ An object sinks if it is more dense than water because the force of gravity acting on the object is stronger than the buoyant force pushing upward

Specific Heat ▪ Specific heat refers to the amount of heat needed to raise 1 gram of water by 1° Celsius. ▪ Water has a high specific heat, meaning it takes a lot of heat to make it get hot. ▪ Water takes a long time to heat up and cool down ▪ This property enables lakes, streams, and ocean ecosystems to maintain a stable temperature, even if the air temperature surrounding the body of water changes drastically.

Capillary Action ▪ Capillary action is the movement of water within the spaces of a porous material ▪ Capillary action works due to the forces of adhesion, cohesion, and surface tension. ▪ This property allows : −water to move through materials with pores inside −causes water molecules to cling to fibers in materials such as paper and cloth −water to rise in a straw/tube.

Universal Solvent ▪ A solvent is any substance, typically a liquid, which is used to dissolve another, different substance. ▪ Water is called the "universal solvent" because it dissolves more substances than any other liquid. ▪ Due to water molecules’ polarity, it can stick to many other substances, disrupt the bonds that hold those substances together, and dissolve them.

Properties of Water Video

Exit Ticket Identify the property of water described below: 1.On a hot summer day, beach sand may quickly warm to the point that it is too hot to stand on while ocean water warms only a little. 2.Ice cubes floating in a glass of water. 3.Salt is added to water and is dissolved. 4.An insect runs across the surface of a pond. 5.The petals of a white flower placed in blue water turn blue.