71% of Earth's surface is covered in water, and 96% of its water is found in the oceans. Without water, Earth would likely be another boring rock in the sky.
Polarity is the "the state of having two opposite or contradictory tendencies, opinions, or aspects." In chemistry, polar molecules have one end that is positively charged and one side that is negatively charged.
Because of their specific electron and proton configurations, each element has an "electronegativity" and an "electron affinity". This indicates how strongly those elements pull on electrons. When electrons are shared between atoms in a molecule, the more electronegative elements pull on those electrons and create an uneven distribution of charge. This creates the polarity that water is famous for.
As a polar solvent, water separates other polar and charged substances (like this NaCl salt) and helps them dissolve.
Life as we know it requires a polar solvent. Our blood is 90% water and helps transport polar salts, minerals, and proteins.
When oxygen pulls electrons away from hydrogen, it creates partial positive and partial negative poles. These partial poles are represented by the Greek lowercase delta, 𝛿. The 𝛿+ from hydrogen in one water molecule will react with the 𝛿- from oxygen in another water molecule. This interaction is known as a "hydrogen bond." Most of the unique and significant properties of water, including many of its life sustaining properties, can be attributed to hydrogen bonding.
For most substances, the density of solid > liquid > gas. Why does solid water float on water? Hydrogen bonding!
Hydrogen bonding can only occur at specific angles. When water freezes, it locks water molecules into a specific shape that is actually less dense than liquid water. This abnormal property allows ice to float.
When scientists measure mass, they often use the "gram" as their reference unit. What exactly is a gram? Originally, the gram was based on the mass of 1 cubic centimeter of water at 4°C. Water is so important to our species, that we compare all other masses to water.
1g = 1000 mg
1g = 0.001 kg
It takes a lot of energy to break the hydrogen bonds that keep water molecules together. Because of these hydrogen bonds, water exists as a liquid for a large range of temperatures. This prevents our blood from boiling or freezing even with large variations in air temperature. The Celsius scale is based on these important temperatures for water.
Why is the temperature at the beach so much lower than the temperature inland? A big part of those temperatures is based on the specific heat of water. Specific heat is the amount of energy that a substance can absorb before it changes temperature. Metals have low specific heat, and will get hot quickly when exposed to heat; water has a relatively large specific heat (primarily because of hydrogen bonding) and requires much more energy to warm up. The energy from the sun is easily absorbed by the ocean, while the concrete in urban areas is more likely to radiate into its surroundings.
4.187 Joule = 1 calorie
The amount of energy needed to raise 1 gram of water by 1 °C is called a "calorie".
1000 calories = 1 kCal = 1 Calorie
Our evolutionary ancestors came from aquatic life. Water's high specific heat prevents big temperature changes in the ocean. Ice's unique density allows it to float above liquid water, which creates an insulating barrier for the water below it. Lakes freeze from the top down, allowing life to survive until warmer seasons arrive.
Cohesion and adhesion allow water molecules to attach to other water molecules and other surfaces. Plants took advantage of these unique properties to transport water large vertical distances energy-free with transpiration, allowing them to grow tall.
Dihydrogen Monoxide warnings might falsely give the public the impression that water is dangerous. Jokes aside, our access to potable water is dwindling and may prove to be a massive socioeconomic issue in the future. Global climate change has shifted weather patterns and made some areas more dry (California) while others are flooding (New Orleans, Miami, and even New York City). Water is the standard for life, and we need to treasure it.
Water is vital to life and one of our first clues we search for when scanning our universe for other life-forms. Use the Scale of the Universe tool to demonstrate the size of various objects in our universe to appreciate the uniqueness of our water planet.
Water is used as the standard or reference for a number of our measurements (degrees celcius, the gram, the calorie). Create a unit chart for some of the more common measurements, and create a new standard for measurement that is more personal.
Add the following code inside of your iframe embed:
onload="this.width=screen.width;this.height=screen.height;"
Copy the clip art links below and use the in-cell embed or =IMAGE() formula in each of your picture cells.
1 pt: Track your water usage by calculating your individual usage via spreadsheet. You can find the exact gallons/flush of your toilet and gallons/minute for your shower, but a value of 2 gal/flush and 2 gal/min can be used if you are unable to find the exact values. Track these values in a spreadsheet and embed it. At least 3 days of data are required for the point
1 pt: Track your water usage by calculating your family's average usage (water bill / # of occupants). Ask your parent's for the water bill information for this value!