It turns out that, however, that no matter how hard you try you can't focus the light to a spot much smaller than the wavelength of the light. An equivalent problem would occur if you tried to use water waves to create a narrow spike of water above the surface—no matter how you worked with the water waves, you would be unable to make them to merge together into a spike that's much narrower than the wavelength of the water waves. Because of his limitation, your spot of light can't be much smaller than the wavelength of light and you can't distinguish between one line or two if those lines are much closer than a wavelength of the light you're using. Since visible light has a wavelength of 400 nanometers or more, you can't use it to resolve details much smaller than 400 nanometers wide.
You can also view the water as an incompressible fluid, one that obeys Bernoulli's equation in the appropriate contexts. As water drifts outward between the impeller blades of the pump, it must move faster and faster because its circular path is getting larger and larger. The impeller blades do work on the water so it moves faster and faster. By the time the water has reached the outer edge of the impeller, it's moving quite fast. But when the water leaves the impeller and arrives at the outer edge of the cylindrical pump housing, it slows down. Here is where Bernoulli's equation figures in. As the water slows down and its kinetic energy decreases, that water's pressure potential energy increases (to conserve energy). Thus the slowing is accompanied by a pressure rise. That's why the water pressure at the outer edge of the pump housing is higher than the water pressure near the center of the impeller.
How can clouds remain aloft?
Many sources claim that clouds remain aloft because the water droplets areso small and widely separated that gravity has less effect on them.
If you make the experiment in a larger roomeven if it is air tight, the water might not rise because it wouldtake too long to burn up all the oxygen and air gets slightly expanded.
You could take some wine and add ethanol to it as the independent variable. The problem is - where do you get ethanol from? Your school may not have a licence to buy 100% (absolute) ethanol, or even the 95% azeotropic mixture (with water) so you may have to distill your own from shop-bought wine (ask your teacher before you bring any to school). From the density of the distillate (use an SG bottle) you can calculate how much to add to some fresh wine.
Sulfur dioxide should prevent the growth of acetic acid bacteria in wine and is sometimes used commercially for this purpose. SO2 in wine consists of the free form (molecular SO2, bisufite ions HSO3-and sulfite ions SO32-) and a bonded form. At normal wine pH only about 5% of the free SO2 occurs in the molecular form (which is the most active anti-microbial form) and the other 95% as bisulfite and sulfite ions. Concentrations of up to 20 mg/L of free SO2 will kill the bacteria.
During the cleaning cycle, one or more pumps operate. They add energy to the water and increase its pressure. This high-pressure water flows slowly to the rotating nozzles and then accelerates to high speeds as it enters the narrow openings and sprays out into the low-pressure cleaning chamber. As the high-speed water collides with the dishes and slows down, its pressure rises again and begins to exert substantial forces on the food particles. The food particles are pushed off the dishes and fall into the bottom of the dishwasher. Soap added to the cleaning water forms tiny spherical objects called micelles that trap and carry away fats that would otherwise not mix with water. At the end of the cycle, the water, food particles, and fat-filled soap micelles are pumped down the drain.
When you place a canning jar in boiling water, what you are really doing is exposing that jar to a water bath at a temperature of 212° F (100° C). Boiling water self-regulates its temperature very accurately, making it a wonderful reference for cooking. Below water's boiling temperature, water molecules evaporate relatively slowly from the surface of water so that when you add heat to the water, it tends to get hotter and hotter. But once the water begins to boil—meaning that evaporation begins to occur within the body of the water—water molecules evaporate so rapidly that when you add heat to the water, more of it converts into steam and its temperature doesn't change much. When you boil canning jars for 5 minutes, you are simply making sure that the canning jars sit at about 212° F for about 5 minutes; long enough to kill bacteria in the jars. Since the boiling temperature of water diminishes at high altitudes and lower atmospheric pressures, you must wait longer for your jars to be adequately sterilized if you live in the mountains.
Your suggestions for why the bubbles appear raise two interesting points. First, in a thermal system such as hot water, you can't identify some molecules as being boiling hot and others as being cooler—temperature is a property of the entire system and not of individual molecules. However, at a given instant, there are molecules with more than their neighbors and it is these energetic molecules that may break free of their neighbors to form a bubble nucleus.
While you can't see it in this unopened bottle, there is activity both at the surface of the water and within the water. At the water's surface, carbon dioxide molecules are constantly leaving the water for the gas under the cap and returning from the gas under the cap to the water. The rates of departure and return are equal, so that nothing happens overall. Within the water, tiny bubbles are also forming occasionally. But these tiny bubbles, which nucleate through random fluctuations within the liquid or more often at defects in the bottle's walls, can't grow. Even though these bubbles contain gaseous carbon dioxide molecules, the molecules aren't dense enough to keep the bubbles from being crushed by the pressurized water. So these tiny bubbles form and collapse without ever becoming noticeable.
Because salty water has a lower chemical potential for water molecules than pure water, water molecules tend to move from purer water to saltier water. This type of flow is known as osmosis. To slow or stop osmosis, you must raise the chemical potential on the saltier side by applying pressure. The more you squeeze the saltier side, the higher the chemical potential there gets and the slower water molecules move from the purer side to the saltier side. If you squeeze hard enough, you can actually make the water molecules move backwards—toward the purer side! This flow of water molecules from the saltier water toward the purer water with the application of extreme pressure is known as reverse osmosis.
Actually, this is the standard invented by Dr. Thomas Clarke, Professor of Chemistry at Aberdeen University, in 1843. A interesting EEI would be to see if the amount of soap needed is correlated with the concentration of various ions responsible for hardness (Ca, Mg). You could make up solutions with a range of concentrations of 'hardness' ions and see how much soap is needed to make a permanent lather (one that lasts for 30 seconds) is obtained when shaken. Try adding dropwise increments of the soap solution from a burette. 'Temporary' hard water can be made by using decanting a saturated solution of Ca(OH)2; and permanent hard water can be made by using either 1 g CaSO4•2H2O or 1 g MgSO4•7H2O in 100 mL water.