S125 - Mod 5

9. What must a lake have in order for it to be a freshwater lake?

A lake must have river outlets in order for it to be a freshwater lake because without those outlets salt would pile up and raise the salinity of the lake.

3. What is the largest source of freshwater on the planet?

The largest source of freshwater is in the glaciers and icebergs.

4. What is the largest source of liquid freshwater on the planet?

The largest source of liquid freshwater on the planet is groundwater.

What is the largest source of liquid freshwater on the planet?

The largest source of liquid freshwater on the planet is groundwater.

Where does the majority of earth's water reside?

The majority of earth's water resides in the oceans as saltwater.

What do the oceans tell us about the age of the earth?

The oceans tell us that the earth is less than 70 million years old, we know this, because we can measure the salinity of the ocean and see the net gain of salt each year

Question: Suppose you are given a sample of water taken from somewhere in earth's hydrosphere. a. Would it most likely be saltwater or freshwater? b. If it is freshwater, where did it most likely come from? c. If the person who collected the sample tells you it is freshwater that originally came from a liquid source, where did it most likely come from?

a. It would most likely be saltwater. After all, more than 97% of the earth's water is ocean water, so the most likely source for water is the ocean. b. If it is freshwater, it most likely came from an iceberg or glacier, since that's the largest source of freshwater on the planet. c. If the person tells you it is from a liquid source, it is most likely groundwater, because groundwater is the largest source of liquid freshwater.

_____ is the result of a cloud forming on the ground. Although this used to be called _______, that term is now generally used to refer to a brownish haze that results from pollution. However, that brownish haze is more properly referred to as ______________________.

Fog is the result of a cloud forming on the ground. Although this used to be called smog, that term is now generally used to refer to a brownish haze that results from pollution. However, that brownish haze is more properly referred to as photochemical smog.

18. Will fog be thicker in a smoky area or an area free of smoke?

Fog will be thicker in smoky area.

13. Where do glaciers come from?

Glaciers come from firn that compresses into ice.

Why is groundwater pollution so hard to trace back to its original source?

Groundwater pollution is difficult to trace because the water converges underground.

The student is correct. The way refrigerators work is by compressing air to heat it up, then decompressing it to cool it down. In normal refrigerators the heat is released into the surrounding air, but if you were to reverse the system you could cool down the surrounding air, and heat up the inside of the refrigerator.

Groundwater pollution is the hardest to track back to its source because once groundwater mixes together; it is very difficult to trace the pollution to its source.

Icebergs are composed of ___________. They do not form as a result of _________ water freezing. In certain polar regions, the water in the ocean does freeze to form ___________, but that is not an iceberg. In fact, icebergs come from ___________, which are the result of snowfall. When a region is cold enough, the ________ does not melt away during the summer. When new snow falls, the old snow gets packed down into what is called ______. As the mass of snow accumulates, it begins to slide to lower elevations, forming a ___________.

Icebergs are composed of freshwater. They do not form as a result of saltwater water freezing. In certain polar regions, the water in the ocean does freeze to form sea ice, but that is not an iceberg. In fact, icebergs come from glaciers, which are the result of snowfall. When a region is cold enough, the snow does not melt away during the summer. When new snow falls, the old snow gets packed down into what is called firn. As the mass of snow accumulates, it begins to slide to lower elevations, forming a glacier.

12. Where do icebergs come from?

Icebergs fall of glaciers as the glacier moves towards the sea.

If a sample of gas is compressed and nothing else is allowed to change, what will happen to the temperature of the gas?

If a sample of gas is compressed and nothing else is allowed to change, the temperature will increase.

17. If no energy is added to air, what happens to the temperature when the air expands?

If no energy is added to air, it cools when it expands in a process called adiabatic cooling.

If there is a lot more rain than normal in an area over an extensive length of time, what happens to the depth of the water table?

If there is excessive rain in an area over an extensive length of time, the depth of the water table increases.

11. If you tasted melted sea ice, would it taste like freshwater or saltwater?

If you tasted melted sea ice, it would taste like saltwater because when you would melt the ice, pockets of highly concentrated saltwater called brine would mix back into the water.

5. In the hydrologic cycle, name the ways water can enter the atmosphere.

In the hydrologic cycle, water can enter the atmosphere through either transpiration or evaporation.

A sailor brings you a chunk of ice that he thinks came from an iceberg. Based on the description of what he saw, however, you think that it might have been a large chunk of sea ice. How could you tell whether the ice is from an iceberg or from sea ice?

Melt the ice and taste the water. If it is salty, it came from sea ice. If it is not salty, it came from an iceberg.

What water source is a molecule of water in once it has gone through transpiration?

Once a molecule of water has gone through transpiration it is in the atmosphere.

One of the real environmental problems that exists today is water ___________, especially what is occurring to the groundwater supply. Since nearly 50% of the United States gets its _______________ from groundwater sources, it has a direct effect on human health.

One of the real environmental problems that exists today is water pollution, especially what is occurring to the groundwater supply. Since nearly 50% of the United States gets its drinking water from groundwater sources, it has a direct effect on human health.

Question: Rain that hits the land can travel as a liquid into a lake, river, stream, or ocean in two different ways. What are they?

Rain on the land can get into another water source via surface runoff or groundwater flow. If the rain never really gets absorbed by the soil, it becomes surface runoff. If it gets absorbed by the soil and enters into the groundwater, it will get to another water source by groundwater flow.

Salt is found in the ocean because the only way water can escape the ocean is through ___________. As Experiment 5.1 shows, when this happens, the ______ is left behind. Thus, the ocean's average salinity ___________ over time. Nevertheless, the salinity of the ocean does vary. Where rivers dump water into the ocean, for example, the salinity is _____ than the average salinity. The average salinity of the ocean indicates it is ______________ than even a few million years old.

Salt is found in the ocean because the only way water can escape the ocean is through evaporation. As Experiment 5.1 shows, when this happens, the salt is left behind. Thus, the ocean's average salinity increases over time. Nevertheless, the salinity of the ocean does vary. Where rivers dump water into the ocean, for example, the salinity is lower than the average salinity. The average salinity of the ocean indicates it is younger than even a few million years old.

What kind of water makes up the majority of earth's water supply?

Salt water makes up the majority of earth's water supply.

16. Suppose you studied two areas of land close to one another. In the first, there are a lot of trees. In the second, there are almost no trees at all. Other than that, the two areas seem identical. They have the same kind of grass and experience the same weather. Which one has the deeper water table?

The area with trees has the deeper water table because the trees there desaturate the soil as they absorb water.

10. Why is the salinity of the ocean evidence that the earth is not billions of years old?

The salinity of the ocean is evidence that earth is not billions of years old because if the earth were billions of years old the salinity of the ocean would be much higher.

Question: Water that was originally in a plant ends up in a cloud. What two processes of the hydrologic cycle caused it to be transferred in that way?

Transpiration and condensation put the water into the cloud. Since it was in a plant, the only way to get it into the atmosphere is by transpiration. At that point, however, it is water vapor, not in a cloud. To be in a cloud, the water vapor must condense.

7. What process in the hydrologic cycle puts soil moisture into the atmosphere?

Transpiration puts soil moisture into the atmosphere as the plants absorb the water.

6. When a raindrop hits the ground, name three ways it can eventually end up in a river.

When a raindrop hits the ground, it can flow directly to the river through surface runoff, it can percolate into the ground and slowly seep towards the river, or it can evaporate again and fall back down to earth as precipitation.

You are studying a sample of soil and want to know if it came from above or below the water table. What could you do to determine this?

Add some additional water to the soil. If the soil absorbs the water, it came from above the water table. If the soil cannot absorb the water, it came from below the water table. Remember, soil below the water table is saturated. If the soil absorbs water, it is not saturated and therefore is not from below the water table.

What causes the temperature change that allows for condensation, which makes most clouds?

Adiabatic cooling causes the temperature change that allows for condensation, which makes most clouds.

19. What kind of cooling is responsible for most cloud formation?

Adiabatic cooling is responsible for most cloud formation.

Adiabatic cooling should not be confused with the fact that most things _________ when they are heated. When you heat something, you are giving it _________. In adiabatic cooling, air is expanding without being given _________.

Adiabatic cooling should not be confused with the fact that most things expand when they are heated. When you heat something, you are giving it energy. In adiabatic cooling, air is expanding without being given any energy.

As glaciers move, they might encounter warmer temperatures, where they begin to _________, feeding various ___________ sources of the hydrosphere. Glaciers in the polar regions often do not encounter warmer temperatures, however, and move all the way to the ocean, where they form ____ ___________. When the edge of a glacier advances into the ocean, the ice ___________ at some points, and large chunks of ice break off the glacier, floating away in the water. This process, called ___________, is what makes an ___________, approximately 90% of which is ________________.

As glaciers move, they might encounter warmer temperatures, where they begin to melt feeding various freshwater sources of the hydrosphere. Glaciers in the polar regions often do not encounter warmer temperatures, however, and move all the way to the ocean, where they form ice shelves. When the edge of a glacier advances into the ocean, the ice weakens at some points, and large chunks of ice break off the glacier, floating away in the water. This process, called calving, is what makes an iceberg, approximately 90% of which is submerged.

Evaporation and condensation of a mixture to separate out the mixture's individual components is called ___________. This process is why water from the ocean can eventually end up in a ___________ source, like a lake, river, or stream.

Evaporation and condensation of a mixture to separate out the mixture's individual components is called distillation. This process is why water from the ocean can eventually end up in a freshwater source, like a lake, river, or stream.

If a lake has a high enough salinity to consider it a saltwater lake, there are __ rivers taking water away from the lake. As a result, the only way water can leave is through ___________. The ___________ is one such lake, and it has a much higher salinity than that of the ocean.

If a lake has a high enough salinity to consider it a saltwater lake, there are no rivers taking water away from the lake. As a result, the only way water can leave is through evaporation. The dead sea is one such lake, and it has a much higher salinity than that of the ocean.

If a lake has no means of getting rid of water except evaporation, it contains saltwater.

If a lake has no means of getting rid of water except evaporation, it contains saltwater.

If a lake were completely isolated from all rivers and streams so that the only way it could get rid of water was by evaporation, would it most likely be a freshwater or saltwater source?

It would be a saltwater source. If evaporation is the only way the lake loses water, it can never get rid of any salt that it gets. So salts keep building up, making the lake a saltwater lake.

What process in the hydrologic cycle is responsible for making glaciers?

Precipitation is responsible for making glaciers. As snow falls on mountains, it can be packed down by more snow if it doesn't melt over the summer. This packed snow eventually compresses into ice and slides down the mountain, forming a glacier.

Question: Suppose a scientist studies two groundwater sources. The first is an underground river that flows quickly into a large lake. The second is a large basin of underground water that moves at a much slower rate towards a small pond. Which groundwater source has the longest residence time?

Residence time measures how long a single molecule of water stays in a water source. The slower the water source exchanges water with other sources, the longer the residence time. Thus, the slow-moving groundwater source will have the longest residence time because groundwater must flow into another source. If it flows slowly, it will take a long time to transfer water.

Saltwater freezes at a _______ temperature than does freshwater. In fact, putting salt on ice will often ______ the ice, because the salt molecules ________ water molecules so that they move away from the other water molecules. When the temperature gets low enough, however, even saltwater will freeze, but the salt and water ___________ as the solution freezes, usually forming solid water that surround little pockets of concentrated saltwater called _______.

Saltwater freezes at a lower temperature than does freshwater. In fact, putting salt on ice will often melt the ice, because the salt molecules attract water molecules so that they move away from the other water molecules. When the temperature gets low enough, however, even saltwater will freeze, but the salt and water separate as the solution freezes, usually forming solid water that surround little pockets of concentrated saltwater called brine.

Soil moisture can flow down through the soil in a process called ___________. If it travels down far enough, it will reach soil that is completely saturated with water. The line between the saturated and unsaturated soil is called the ______________. The depth of this line __________ over time. For example, when there is a period of very heavy rains, the depth ___________, and when there are periods of little or no rain, the depth ___________.

Soil moisture can flow down through the soil in a process called percolation. If it travels down far enough, it will reach soil that is completely saturated with water. The line between the saturated and unsaturated soil is called the water table. The depth of this line varies over time. For example, when there is a period of very heavy rains, the depth increases, and when there are periods of little or no rain, the depth decreases.

Suppose you analyzed the salinity of three samples of ocean water. One was taken from deep in the ocean, one was taken from near the surface, and one was taken from a place near where a large river emptied into the ocean. If the salinities of samples 1, 2, and 3 were 37 grams per kilogram, 25 grams per kilogram, and 35 grams per kilogram, respectively, which sample was taken near the river?

Suppose you analyzed the salinity of three samples of ocean water. One was taken from deep in the ocean, one was taken from near the surface, and one was taken from a place near where a large river emptied into the ocean. If the salinities of samples 1, 2, and 3 were 37 grams per kilogram, 25 grams per kilogram, and 35 grams per kilogram, respectively, which sample was taken near the river?

The average time a given particle will stay in a given system is called its ___________, and in the hydrologic cycle, it varies considerably from source to source. The average time a molecule of water stays in a swiftly flowing river, for example, is ___________ than that of a water molecule in a lake. The average time a molecule of water stays in the atmosphere is much __________ than that of a water molecule in the ocean. The _______ was the first work to mention the hydrologic cycle.

The average time a given particle will stay in a given system is called its residence time, and in the hydrologic cycle, it varies considerably from source to source. The average time a molecule of water stays in a swiftly flowing river, for example, is much shorter than that of a water molecule in a lake. The average time a molecule of water stays in the atmosphere is much shorter than that of a water molecule in the ocean. The Bible was the first work to mention the hydrologic cycle.

15. The captain of a ship sees an iceberg and steers clear of it. Why is the captain still worried about a collision?

The captain is still worried about a collision because although he avoided the top of the iceberg, the remaining 90 percent of that iceberg is somewhere under the water.

The chemical name of the salt you put on your food is _____________. Although this is the majority of salt in the ocean, chemists use the tem "salt" more ___________, and as a result, there are other salts in the ocean. A measure of the mass of dissolved salt in a given mass of water is called ___________.

The chemical name of the salt you put on your food is sodium chloride. Although this is the majority of salt in the ocean, chemists use the term "salt" more liberally, and as a result, there are other salts in the ocean. A measure of the mass of dissolved salt in a given mass of water is called salinity.

In a certain region, the depth of the water table is measured. If there is a lot less rain than usual over the summer, what will happen to the depth of the water table?

The depth of the water table will increase. The water table separates saturated soil from unsaturated soil. With little rain, groundwater flow will deplete the saturated soil faster than percolation will replace it, and soil that used to be saturated will become unsaturated. That means the water table will be deeper than before.

An enormous amount of ocean water in the polar region freezes. Does it form an iceberg? Why or why not?

The frozen ocean water forms a large chunk of sea ice; however it does not form an iceberg. An iceberg forms specifically when part of a glacier (freshwater) falls into the sea.

The process by which water is continuously exchanged between earth's various water sources is called the ______________. In this process, water gets into the atmosphere predominantly by ___________ and ___________. Soil moisture is usually depleted by either ___________ or _________________. Water vapor in the atmosphere can form a cloud through a process called ___________. Once water is in a cloud, it can fall back to earth as ___________. When this water falls on land and then runs along the surface into a lake, river, or stream, we call it _____________.

The process by which water is continuously exchanged between earth's various water sources is called the hydrologic cycle. In this process, water gets into the atmosphere predominantly by evaporation and transpiration. Soil moisture is usually depleted by either transpiration or groundwater flow. Water vapor in the atmosphere can form a cloud through a process called condensation. Once water is in a cloud, it can fall back to earth as precipitation. When this water falls on land and then runs along the surface into a lake, river, or stream, we call it surface runoff.

Where is the residence time longer: in the ocean or in a fast-moving stream?

The residence time is longer in the ocean because in the ocean the only way water can escape is by evaporating.

8. In which body of water would the residence time be shorter: a quickly moving river or a lake that has no river outlets?

The residence time would be shorter in the quickly moving river because the water in the flow river can quickly flow whereas the water in the lake has to evaporate.

20. A bright student notes that with a few modifications, a refrigerator can become a "hot box," keeping things warm instead of cold. Explain.

The student is correct. The way refrigerators work is by compressing air to heat it up, then decompressing it to cool it down. In normal refrigerators the heat is released into the surrounding air, but if you were to reverse the system you could cool down the surrounding air, and heat up the inside of the refrigerator.

Suppose you have a balloon whose volume you can change. You inflate it to a volume of 1 liter and measure the temperature of the gas inside. You then very quickly compress the balloon so that its volume is only 0.5 liters. What happens to the temperature of the gas inside?

The temperature will increase. Since air cools when it expands, it will warm when it is compressed, unless energy is removed in the process.

14. What is the term for the process by which a portion of a glacier breaks off and falls into the water?

The term for the process by which a portion of a glacier breaks off and falls into the water is calving.

The vast majority of earth's water supply is contained in the _________ as ___________. The vast majority of earth's freshwater supply is stored in _________ and ________. The largest source of liquid freshwater is ___________. Aside from the sources just mentioned, the other major sources of water in the hydrosphere are ___________ (not oceans), ___________, and _________________.

The vast majority of earth's water supply is contained in the oceans as saltwater. The vast majority of earth's freshwater supply is stored in glaciers and icebergs. The largest source of liquid freshwater is groundwater. Aside from the sources just mentioned, the other major sources of water in the hydrosphere are surface water (not oceans), moisture in the atmosphere, and soil moisture.

Water was in the ocean and is now in a cloud. What two hydrologic cycle processes happened in order to make that transfer?

The water in the ocean evaporated to be transferred to the atmosphere, once it was in the atmosphere it condensed on to cloud condensation nuclei.

Water in the atmosphere exists as either ___________ or ________. In order for clouds to form, there must be _____________________ upon which water can condense. This condensation occurs because as air expands, it gets _________. The scientific name for this process is ________ ___________. Water in clouds can be either _________ or _______, depending on the temperature.

Water in the atmosphere exists as either clouds or water vapor. In order for clouds to form, there must be cloud condensation nuclei upon which water can condense. This condensation occurs because as air expands, it gets colder. The scientific name for this process is adiabatic. Water in clouds can be either liquid or solid, depending on the temperature.

Water is such a large part of the earth that astronomers often call it the _______ planet. The sum of all water on a planet is called its ___________. Of all the planets in our solar system, earth is the ___________ that has a large quantity of water in its liquid form. This is because the earth has _______________________ in its atmosphere and is __________________________ from the sun.

Water is such a large part of the earth that astronomers often call it the blue planet. The sum of all water on a planet is called its hydrosphere. Of all the planets in our solar system, earth is the only one that has a large quantity of water in its liquid form. This is because the earth has just the right mixture of gases in its atmosphere and is just the right distance from the sun.

Define the following terms: a. Hydrosphere b. Hydrologic cycle c. Transpiration d. Condensation e. Precipitation f. Distillation g. Residence time h. Salinity i. Firn j. Water table k. Percolation l. Adiabatic cooling m. Cloud condensation nuclei

a. The hydrosphere is the mass of all water on a planet. b. The hydrologic cycle is the process that moves water around into different sources, using various methods such evaporation, precipitation, and groundwater flow. c. Transpiration is the process of water evaporating from plants. d. Condensation is the process of gas impacting a cold surface and condensing into a liquid. e. Precipitation is liquid or frozen water that falls out of clouds. f. Distillation is the process of boiling two or more substances to separate them. Since the substances will likely boil at different temperatures, one will be turned into a gas while the other heats up. g. The residence time of a molecule is the time it will take for that molecules to be transferred to another system. h. Salinity is the amount of mass dissolved in water. i. Firn is very dense snow caused by snow not melting during the year and being packed down by new snowfall. j. The water table is layer between the saturated layer of water and the soil. k. Percolation is the act of water seeping down through the ground. l. Adiabatic cooling happens when a gas expands without gaining energy. Since the gas is spread out, it doesn't collide with other surfaces as often, it doesn't transfer as much energy to other surfaces, and thus, the surface cools. m. Cloud condensation nuclei are small particles up in the atmosphere that water molecules can gather around to form clouds.

Define the following terms: a. Transpiration b. Condensation c. Residence time d. Percolation e. Adiabatic cooling

a. Transpiration is the process of water evaporating from plants. b. Condensation is the process of a gas turning into a liquid. c. The residence time of a substance is the average time it will remain in a system. d. Percolation is the process of water soaking down through soil to the water table. e. Adiabatic cooling is the cooling of a gas caused by the gas expanding. When the gas expands, its heat energy is spread out, effectively cooling its surrounding matter.