Physics

Physics idea.

Surface Tension, Hydrophilic and Hydrophobic Interactions
Water binds to //hydrophilic// (water-loving) surfaces because such surfaces have slight electrical charges; it beads up on //hydrophobic// (water-hating) surfaces because they have no charges and the water would rather mingle with itself than mess around with something that has no charge

test the charge of the water at different temperatures?

- []

density of water at different temperatures which affects the living organisms

"Very small organisms also try to manipulate their density, but their efforts are often more difficult to explain. Diatoms, for instance, must stay near the surface to obtain enough light for photosynthesis, yet they have a heavy shell of silica. They offset the shell to some extent by a store of oil, but they still "worry" about sinking. Fortunately, the world of very small organisms is governed by different rules than the world we live in. To them, water is more like molasses and sinking rates are very small, often small enough to be offset by local currents caused by the water heating and cooling. The heating and cooling of the water also changes its density, and, for small organisms in particular, this is not a trivial matter. The change in density of water from 4o C to 25o C is large enough to mean the difference between floating and sinking in many organisms with densities near that of water. It is easier to float in denser water, and fresh water is most dense at 4o C (Fig. 3). Salt increases density of water (Fig. 4); it is easier to float in salt water as opposed to fresh water, and easier still in hypersaline environments such as the Great Salt Lake in Utah. It is not unusual for populations of small organisms to undergo seasonal morphological changes at least partially in response to temperature induced water density changes; one of the best examples is //Daphnia// (see Vogel, 1981, pages 23-24)."

get a sample of the water and then heat it to different temperatures to test the densities.

test the conductivity of the water at different areas which have different pollution levels to test if pollution in the water can affect the electrical ability.
have eight different samples of water (five samples from each position) and test how conductive the water is using a circuit. - create a circuit using wires, light bulb, power pack and test how bright the light is with the same voltage from the battery. - use a multi meter to test the voltage/resistance

FINAL EXPERIMENT []

by using the method from this website (however not creating wires to go to the water as the samples can be tested on site) collect 5 samples from eight different locations of water from west lake. - of different pollution levels once they are collected, use the multi meter to test the resistance of each sample. then create averages for each and graph. the website says: " Pure water (distilled or deionized) lacks the ions to carry current and will test as very high resistance, 10 MegOhm or above" therefore the samples with the highest resistance are the purest and with lower/lowest resistance are less pure.  independent variable: the area which is being measured dependent variable: the resistance of the water and what this means - pure water or polluted water  []  How the data will be recorded. five different samples from the same area will be taken and measured. once they are measured, i will find an average of the resistance and graph these against each other (using a scatter graph) and then i will be able to see where the most polluted area was (with the lowest resistance) and where the least polluted area was (with the highest resistance).  example of table to record data  Resistance || Sample 2 Resistance || Sample 3 Resistance || Sample 4 Resistance || Sample 5 Resistance ||  after getting the samples and coming back to school to carry out the experiment, Ms. Renneberg found that i was not actually measuring resistance with the multi-meter but that i was measuring the voltage. I tried measuring the resistance however the meter did not give me any readings so i continued taking readings of the voltage as this gave qualitative data. Afterwards i did some research about what current in a liquid relates to and i found the following website.   []  > > The specific conductance test measures the ability of water to pass an electrical current. Conductivity in water is affected by the presence of inorganic dissolved solids such as chloride, sulfate, sodium, calcium and others. > Conductivity in streams and rivers is affected by the geology of the area through which the water flows. Streams that run through granite bedrock will have lower conductivity, and those that flow through limestone and clay soils will have higher conductivity values. <span style="background-color: #ffffff; color: #ff0000; font-family: Arial,Helvetica,sans-serif;">High conductance readings can also come from industrial pollution or urban runoff -- water running off of streets buildings, and parking lots. Extended dry periods and low flow conditions also contribute to higher specific conductance readings. > <span style="background-color: #ffffff; color: #ff0000; font-family: Arial,Helvetica,sans-serif;">Because an organic compound such as oil does not conduct electrical current very well, an oil spill tends to lower the conductivity of the water. Temperature also affects conductivity; warm water has a higher conductivity. Specific conductance is measured in microsiemens per centimeter (µs / cm). Expected levels: 300 to 700 µs /cm in most of the Colorado River watershed; higher near San Saba and the coast." > > =<span style="font-family: Arial,Helvetica,sans-serif; text-align: left; vertical-align: baseline;">__Data found during experiment__ = =<span style="font-family: Arial,Helvetica,sans-serif; text-align: left; vertical-align: baseline;"> = Right of the dragon statue ||  0.33  ||  0.31  ||  0.31  ||  0.30  ||  0.30  ||  0.31    ±0.02  || By the dragon statue ||  0.35  ||  0.32  ||  0.34  ||  0.30  ||  0.31  ||  0.32    ±0.03  || No fishing area ||  0.08  ||  0.07  ||  0.07  ||  0.07  ||  0.06  ||  0.07    ±0.01   || Opposite the lotus fields ||  0.14  ||  0.10  ||  0.10  ||  0.11  ||  0.10  ||  0.11    ±0.02  ||
 * Area || Sample 1
 * Area 1 ||  ||   ||   ||   ||   ||
 * Area 2 ||  ||   ||   ||   ||   ||
 * Area 3 ||  ||   ||   ||   ||   ||
 * Area 4 ||  ||   ||   ||   ||   ||
 * Area 5 ||  ||   ||   ||   ||   ||
 * Area 6 ||  ||   ||   ||   ||   ||
 * Area 7 ||  ||   ||   ||   ||   ||
 * Area 8 ||  ||   ||   ||   ||   ||
 * <span style="background-color: #ffffff; font-family: Arial,Helvetica,sans-serif; font-size: 12px;">**"Specific conductance**
 * **Area** || **Sample 1**
 * Voltage**
 * ±0.01** || **Sample 2**
 * Voltage**
 * ±0.01** || **Sample 3**
 * Voltage**
 * ±0.01** || **Sample 4**
 * Voltage**
 * ±0.01** || **Sample 5**
 * Voltage**
 * ±0.01** || **Average and unc.** ||
 * **Area 1**
 * **Area** **2**
 * **Area 3**
 * **Area 4**