Introduction: (Initial Observation)
Rain and snow are the main sources of fresh water for people living on the earth. Both rain and snow come from the clouds; but, where do the clouds come from? It often seems that clouds appear from nowhere. One minute the sky is clear and then a few minutes later clouds form. Sometimes clouds come from far places. Wind moves the clouds from one area to the other.
If you live near a lake, ocean or forest, you may have seen water vapors rising from wet surfaces and disappearing in the air. Is it possible that the same vapors become visible again when they get to higher elevations? If the clouds come from oceans, forests and other surface waters then why doesn’t the rain water contain salt and other pollutants that exist in rivers and surface waters?
Is it possible that only pure water evaporates and all impurities stay behind?
In this project you will study, observe and demonstrate the water cycle.
Adult supervision and support is required for the experiments of this project.
Find out what happens to the water that evaporates. Read books, magazines or ask professionals who might know in order to learn about water evaporation, clouds and precipitation. Keep track of where you got your information from.
Following are samples of information that you may find:
The Water Cycle
Earth was formed 4.6 billion years ago, but water was not present from the very beginning. At some point, possibly because of the heating of hydrogen and oxygen as Earth developed, water vapor began to form in the atmosphere. About 3.8 billion years ago, oceans formed and the cycle began. The same water that you drink today has been around since the oceans formed. Water is an important part of life on this planet. The water cycle is a complex process that gives us water to drink and provides us with climates that allow us to have food to eat. The earth has a limited amount of water, which keeps going around and around. It is a very important cycle in that it allows for life and helps sustain life on earth. Seventy percent of the earth’s surface is covered by water. Yet only 1% of that water is in the form to be used by humans and land animals. Water constantly changes from solid to liquid to gas. This cycle is what we call the water cycle.
Evaporation, condensation, and precipitation are the cycles of the water cycle.
Evaporation occurs when the sun heats up water in our oceans, lakes, and rivers and turns it into vapor or stream. This water vapor leaves the oceans, lakes, and rivers and moves up into the air. The water vapor settles in the troposphere where it condenses.
Condensation happens when warm and cold air meets in the troposphere. The water vapors in the air get cold and excess water condenses into either liquid water or ice, which then form clouds. If enough of this water forms into clouds, rain will begin if the weather is warm. If it is cold, it will snow. This process is called precipitation.
Precipitation is when so much water has condensed that the air cannot hold it any longer. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow.
Essentially water in liquid form turns into a gas, then into a solid, and finally back into a liquid in a never-ending process.
Do some research on water cycles, and draw a diagram to help you further understand this important cycle of the earth. Once you understand the water cycle and have done some research on it, you can observe the cycle in your own home. The links below should be very helpful in this preparation process. They should be used as a complement to your own research.
If you live in the United States, there are 40 trillion gallons of water above your head on an average day. Each day, about four trillion gallons of this water fall to Earth as precipitation, such as rain, snow, or hail. Some of the water that falls to Earth soaks into the ground and provides runoff to rivers, lakes, and oceans. The remainder—more than 2.5 trillion gallons—returns to the atmosphere through evaporation, and the process begins again.
This continuous process of precipitation and evaporation is called the water cycle, or hydrologic cycle.
Evaporation is when the sun heats up water in rivers or lakes or the ocean and turns it into vapor or steam. The water vapor or steam leaves the river, lake or ocean and goes into the air.
Sample Experiment to show condensation
In this experiment we will go through all the water cycles and recreate them at home to further understand how they affect the whole world.
You can observe condensation very simply with a few items from around your house. Pour cold water into a glass and put it out on a hot day. You will see water form on the outside of the glass after a few minutes. Water vapor in the warm air turns back into liquid when it touches the cold glass.
You can also view evaporation very easily in your home. Have a parent assist you with putting some water in a kettle, and letting it come to a boil. As the water in the kettle becomes heated, you can watch the steam rise out of the kettle. The water is evaporating into the air.
You can then take a ceramic plate and put it in your freezer for an hour. Then take the plate out of the freezer and hold it about 1 ft. over the steam rising out of the kettle. Be careful that the steam does not burn your hands. You will see water droplets form on the plate. This is then called condensation. If a lot of water condenses on plate, it will start dripping down and this in turn is called precipitation!
In this same way that you viewed the water cycle in your home, the water cycle occurs on our earth. What is the importance of what you have just done? Summarize what you just observed in your experiments. Describe exactly what happened and try to think of the implications of these procedures.
What do you want to find out? Write a statement that describes what you want to do. Use your observations and questions to write the statement.
The purpose of this project is to display water cycle. Show how the light and heat energy from the sun evaporate water and distributes water around the earth.
When you think you know what variables may be involved, think about ways to change one at a time. If you change more than one at a time, you will not know what variable is causing your observation. Sometimes variables are linked and work together to cause something. At first, try to choose variables that you think act independently of each other.
As a display project, you will not need to identify variables. In higher grades you may want to study the effect of one specific factor on the rate of evaporation or condensation. That is when you need to define variables.
For example you may want to study the effect of temperature on evaporation of water. In this case temperature will be the manipulated variable. The rate of evaporation is the responding variable.
Another example is when you want to determine the evaporation rate in different days. (Experiment 3). In this case the independent variable is the day. The dependent variable is the amount of water evaporation from one square foot surface water.
Based on your gathered information, make an educated guess about what types of things affect the system you are working with. Identifying variables is necessary before you can make a hypothesis.
In a display project, you will not need to identify variables.
Design an experiment to test each hypothesis. Make a step-by-step list of what you will do to answer each question. This list is called an experimental procedure. For an experiment to give answers you can trust, it must have a “control.” A control is an additional experimental trial or run. It is a separate experiment, done exactly like the others. The only difference is that no experimental variables are changed. A control is a neutral “reference point” for comparison that allows you to see what changing a variable does by comparing it to not changing anything. Dependable controls are sometimes very hard to develop. They can be the hardest part of a project. Without a control you cannot be sure that changing the variable causes your observations. A series of experiments that includes a control is called a “controlled experiment.”
Experiment 1: What evaporates?
Introduction: Rain and snow do not contain salt and other pollutants usually found in the sea or other surface waters. In this experiment you will test to see if such material may evaporate along with water.
- Make some salty-polluted water by dissolving some salt and some water color in a cup of water.
- Transfer your polluted water to a plate and leave it outside under the sun for water to evaporate.
- After a few days, see weather the salts and water color evaporated or if they remained on the plate.
- Based on the result, write your conclusion.
Experiment 2: Water Displacement?
Introduction: Evaporation, condensation and precipitation are parts of a process that transfer large amounts of water from oceans to dry lands all over the globe on a daily bases.
This process is called water cycle. Without this process rivers, forests and lakes could not exist. In this experiment we will examine the process of water cycle and see how water is transferred from one area to the other.
- Get a two compartment plastic container with a lid that seals perfectly. Make sure that the divider is shorter than the sides of the container; in this way air can freely flow between the two compartments.
- Place the container on a flat surface in a sunny place in your backyard and then place a piece of stone or a block of wood under one side of the container. In this way the container will be slanted to one side.
- Fill the elevated compartment in half with water. Carefully place the lid on and cover the lower compartment with an aluminum foil to keep it cool.
- After 7 days carefully open the container. What do you see in the lower compartment. Can water evaporate from one compartment and condense and precipitate in the other compartment?
The above experiment can also be performed in a glass or plastic aquarium.
A slanted glass on top allows the condensations to go towards elevations that you may make using real soil or a block of Styrofoam.
Use plastic plants or dry plants on the elevations to simulate vegetations.
What if we have no sunlight?
A 100 watt flood lamp mounted about 1 foot above the water area can work like sunlight. You may use a timer or manually turn off an on the light every hour to create day and night conditions for your model.
Experiment 3: Rate of water cycle
Introduction: The water cycle starts by evaporation of surface waters and perspiration by plants, and it ends when the water comes back down to the earth in the form of rain or snow. In this experiment you measure and record the amount of water evaporating from surface waters in different days.
Who must do this experiment?
If you are required to have a data table and possibly a graph for your project, you may try this experiment. In most cases 8th grade students are expected to present a data table and a graph with their project report or project display.
Measure 250 milliliters of water in a graduated cylinder and then transfer the water to a flat, square cooking tray. Try to use a tray that has an area of one square foot. If you don’t have a tray that measure one square foot, you can make one using an aluminum foil placed over a cardboard.
Place the tray outside in an open space, away from animals and birds.
After 24 hours transfer the water back to the measuring cylinder and observe the difference. Record how much water was evaporated.
Repeat this experiment in 5 different days and record the amount of evaporated water per square foot. Also record the outdoor weather temperature on those days.
Your results table may look like this:
|Day||Temperature||Daily Evaporation/ sq. ft.|
|Average Daily Evaporation from each square foot|
Calculate and write the average daily evaporation in the last row of your data table.
Make a graph:
You can use a bar graph to visually present your results. Make one vertical bar for each day you repeat your experiment. The height of bar will show the amount of daily evaporation on that day.
If for some reason such as rain or animals your results become invalid, you will have to ignore the results of such days. If you have time, you may repeat your test a few more days to have at least 5 days of reliable results.
Materials and Equipment:
Material used in the above experiments are:
- Water Color
- Clear plastic container with 2 compartment
- Plastic aquarium
- Light bulb (100 watt) to simulate sunlight
Results of Experiment (Observation):
Experiments are often done in series. A series of experiments can be done by changing one variable a different amount each time. A series of experiments is made up of separate experimental “runs.” During each run you make a measurement of how much the variable affected the system under study. For each run, a different amount of change in the variable is used. This produces a different amount of response in the system. You measure this response, or record data, in a table for this purpose. This is considered “raw data” since it has not been processed or interpreted yet. When raw data gets processed mathematically, for example, it becomes results.
No calculations are required for this project.
Summary of Results:
Summarize what happened. This can be in the form of a table of processed numerical data, or graphs. It could also be a written statement of what occurred during experiments.
It is from calculations using recorded data that tables and graphs are made. Studying tables and graphs, we can see trends that tell us how different variables cause our observations. Based on these trends, we can draw conclusions about the system under study. These conclusions help us confirm or deny our original hypothesis. Often, mathematical equations can be made from graphs. These equations allow us to predict how a change will affect the system without the need to do additional experiments. Advanced levels of experimental science rely heavily on graphical and mathematical analysis of data. At this level, science becomes even more interesting and powerful.
Using the trends in your experimental data and your experimental observations, try to answer your original questions. Is your hypothesis correct? Now is the time to pull together what happened, and assess the experiments you did.
Related Questions & Answers:
What you have learned may allow you to answer other questions. Many questions are related. Several new questions may have occurred to you while doing experiments. You may now be able to understand or verify things that you discovered when gathering information for the project. Questions lead to more questions, which lead to additional hypothesis that need to be tested.
If you did not observe anything different than what happened with your control, the variable you changed may not affect the system you are investigating. If you did not observe a consistent, reproducible trend in your series of experimental runs there may be experimental errors affecting your results. The first thing to check is how you are making your measurements. Is the measurement method questionable or unreliable? Maybe you are reading a scale incorrectly, or maybe the measuring instrument is working erratically.
If you determine that experimental errors are influencing your results, carefully rethink the design of your experiments. Review each step of the procedure to find sources of potential errors. If possible, have a scientist review the procedure with you. Sometimes the designer of an experiment can miss the obvious.
Q. Since this project doesn’t have results or data, then how would I set up the project board. Is there an Abstract, conclusion or a purpose?
A. In a display project you do the experiments and write down your observations as the experiment results. Project board will have drawings, pictures and writings similar to what you have in your project guide. In addition to that you also write your observations and what you have learned from your experiments.
If you need to have a data table, you can repeat the experiment 2 in 5 different days and record the amount of water displacement every day. Then convert the values to the ratio of total water in the container.