Integrated Science

• Water is part of a deeply interconnected system
• What we pour on the ground may end up in a body of water far away, may go to the atmosphere, and go back to our source of potable water
• Water cycle


  The journey of water as water molecules make their way from the Earth's surface to the atmosphere and back again, in some cases to below the surface

  
• Water cycle


  • Powered by energy from the Sun
  • A continuous exchange of moisture between the oceans, the atmosphere, and the land
• Hydrologic cycle


  1. Thermal energy from the Sun evaporates water from the Earth's surface

  2. Water vapor is carried up in the atmosphere by rising air

  3. Water vapor condenses to form clouds

  4. Precipitation falls back to Earth

  5. Some precipitation soaks into the ground as groundwater

  6. Gravity moves water downhill as runoff to the oceans
• Water on Earth that moves through the water cycle is stored in different reservoirs

  
• Importance of hydrologic cycle

  • It is how water becomes available to all living organisms
  • Evaporation and infiltration naturally purify water
  • Rainfall and surface runoff play essential roles in recycling other matter on Earth
  • It sustains life by maintaining plant growth through precipitation
  • It regulates global weather patterns and temperature

  
• Water cycle


  1. You are a drop of water in the ocean

  2. Describe your trip through the water cycle
• Water


  Chemical formula H₂O, naturally exists on Earth in its three phases, hydrogen atoms and oxygen atom joined by covalent bond

  
• Covalent bond


  Type of chemical bond where two atoms share their electrons with each other
• Polarity


  H₂O is a polar molecule, meaning there is an unequal distribution of electrons within the molecule

  
• Hydrogen bond


  Formed between water molecules when partially positive H is attracted to nearby other molecules' negative O

  
• Cohesion


  Water molecules are attracted to each other and stick together because of hydrogen bonds
• Surface tension


  The cohesive force between water molecules is so strong that it creates a surface tension that can resist an external force
• Adhesion


  Water molecules are attracted to other objects, like glass, plastic, or even leaves
• Capillary action


  Strong cohesion and adhesion of water molecules enable them to move upward against gravity in a narrow tube
• Capillary action


  Occurs when the adhesion of water to the surface material is stronger than the water molecules' cohesive forces
• Water as solid (ice)


  Below 0°C, water is solid, molecules align into a crystal lattice and are spaced further apart
• High specific heat


  Water has high specific heat capacity, the amount of heat that must be absorbed or lost for 1 gram to change temperature by 1°C
• The greater the specific heat capacity, the greater the heat required to increase its temperature
• Water molecules create strong hydrogen bonds, heat is needed to be absorbed first to break hydrogen bonds
• Pure water at sea level boils at 100°C
• Evaporative cooling


  Heat of vaporization is the amount of heat needed to turn 1 gram of a liquid into water vapor (gaseous state)
• Evaporative cooling


  1. When water is heated, the liquid's average kinetic energy increases enough to break molecular attractions and escape the air as gas

  2. The surface of the liquid where evaporation occurs cools down
• Sweat uses body heat from our skin and evaporates, taking away heat in our skin and decreases body temperature
• Soil is made up of what?

  1. 45% organic matter
  2. 25% water
  3. 25% air
  4. 5% organic matter
• Soil profiling


  Structure, texture, and horizons

  
• Sedimentary Processes


  1. Weathered rocks are mixed with mineral, organic matter, water, and air

  2. This mixture is SOIL

  3. About half of the soil's components are decomposed rocks and humus

  
• Soil texture


  The proportions of the particle size in the soil

  
• Soil texture


  • Greatly affects the soil's ability to retain and transmit water and air, which is essential for plant growth
• Soils rich in a single size of particle is rare, hence textural categories have been established
• Soil structure


  • Soils usually form clumps called peds, which provide the basis for a particular structure to the soil
  • The soil structure influences the permeability and porosity of the soil, and affects the movement of nutrients to the roots of plants
• Soil's pH level


  A measure of how acidic or basic a substance is, which affects the growth of plants

  
• Primary macronutrients


  • Nitrogen (N)
  • Phosphorous (P)
  • Potassium (K)
• Other elements, such as iron, are just as critical to plant survival but plants need them in much smaller quantities
• Soil horizons


  The soil-forming process happens from the surface downward, and the composition, structure, and color of the soil gradually change with depth

  
• Soil textural categories


  • 30% clay, 40% silt, 30% sand
  • 15% clay, 50% silt, 35% sand
  • 5% clay, 30% silt, 65% sand

  
• Porosity


  The measure of the void spaces in the soil and the measure of its ability to hold a fluid
• Permeability


  The measure of the ability of soil to transmit fluids and the measure of the ease of flow of a fluid through a porous solid
• Eluviation


  The finer soil particles are carried away as water permeates through the soil layers (horizon E)