Water Test Part 1 - Science

How much of the earth is covered by water?

1. 71%

   1. Saltwater: 97%

   2. Freshwater: 3%

Explain what a water molecule looks like, including why water sticks together (cohesive):

1. H₂O: there are 2 hydrogen atoms and 1 oxygen atom

2. The hydrogen end is positively charged, while oxygen end is negatively charged

3. The positive ends will attract the negative ends of molecules (hydrogen bonds)

1. What are some of water's special properties?

1. Water can absorb a lot of energy b/f it changes temperature

2. Water can dissolve many substances (substances can spread out)

3. Ice is less dense than water it floats/water expands as it freezes

Is fresh water distributed evenly across the earth's surface? 

1. No, some areas have a lot more freshwater than others

Why do humans need to be careful using groundwater?

1. We need to be careful that we don't take it out faster then the rain replenishes it

 What are some pros and cons of dams?

1. Gives us access to drinking water, generates energy

2. Cons: really bad for river ecosystems and fish, dam failure and kill, sediments get blocked by the dam (they have nutrients) 

What are two ways desalination happens?

1. Boiling salt water

2. Filter ocean water through a very fine membrane

 What happens to water that hits earth's land surface? 

1. Evaporates out of the soil

2. Infiltrates into the ground

3. Runoff into body of water

 How does surface water become groundwater?

1. It seeps into the ground if there are pore spaces in the rock/soil/sand layers 

 What is the connection between vegetation and infiltration?

1. The more vegetation = more infiltration of water

What is the connection between runoff and land’s slope?

1. Steeper the land = the more runoff (less infiltration) 

The three biggest watersheds in the world?

1. Amazon 

2. Nile

3. Mississippi

 How does a river delta form?

1. Rivers flowing downstream have a lot of sediments, these get deposited when the river flows into a ocean

 Are all lakes naturaling occurring?

1. No, some are made by damming a river - the reservoir

2. Natural lakes form different ways, ex) Glaciers melting filling up big divets in land

How does eutrophication happen?

1. It does occur naturally but it is increased by humans using fertilizers (that have nutrients in them)

 Why are wetlands so important?

1. They act as a filtration system, removing pollutants, sediments, bacteria from water before it enters the ocean 

2. Very important habitat for many species 

Protects the coast from flooding