The makers of sports drinks spend millions of dollars advertising the benefits of their products. One of these featured benefits is often electrolytes, which your body loses as you sweat. In this chemistry science fair project, you will compare the electrolytes present in a sports drink with those in orange juice to find out which drink has more to replace the ones you lose as you're working out or playing sports. When you are finished, you might even want to make your own sports drink! Objective
To investigate whether or not a sports drink provides more electrolytes than orange juice. Introduction
"Just do it!" You've heard the slogan, and there is no doubt that exercise is a key part of staying healthy. Most experts agree that if you are engaged in light to moderate exercise, water is just fine. But if you are exercising strenuously, you might need to replace some of the salts that your body loses through sweat. These salts, or electrolytes, are found in most sports drinks. What are the advantages of a sports drink over water? Water will provide the liquid you need to avoid dehydration, but does not have electrolytes. Anelectrolyte is a substance that will dissociate into ions in a solution. The ions in the solution give it the capacity to conduct electricity. Electrolytes, such as sodium and potassium, are present in sweat, and need to be replaced during strenuous exercise. Chloride, calcium, and phosphate ions are also electrolytes. The proper concentration of electrolytes in your blood is essential for health. Your cardiovascular and nervous systems, to name just two, require electrolytes to function. Concentration gradients of sodium and potassium across the cell membrane produce the membrane potential and provide the means by which electrochemical impulses are transmitted in nerve and muscle fibers. The concentration of the various electrolytes in body fluids is maintained within a narrow range. Stability of the electrolyte balance depends on adequate intake of water and electrolytes. The maintenance of electrolytes within this narrow range is due to homeostatic mechanisms within the body, which control the absorption, distribution, and excretion of water and its dissolved electrolytes. But can you get your electrolytes from natural juices, such as orange juice? One problem with juice is that many have relatively high concentrations of carbohydrates, which is fine for your morning drink, but not ideal for re-hydrating during exercise. High levels of carbohydrates add useless calories and require water for digestion. To measure the electrolytes in this science fair project, you will use a multimeter. A multimeter is an electronic device that measures voltage, current,and resistance. For this science fair project, you will just use the ammeter part of the multimeter. An ammeter measures current. How can you use an ammeter to measure the concentration of electrolytes? You will use it to measure conductance, which is proportional to the electrolyte concentration. Because electrolytes are charged particles that carry current in solution, the conductance of the solution depends on the concentration of the electrolytes. If you increase the concentration of electrolytes in a solution, the conductance of the solution also increases. In order to measure a current in the solutions, you have to apply a voltage. You will use a 9-volt (V) battery to supply the voltage. Conductance is measured in units, called siemens, and has the symbol G. The symbol for current is I, and it is measured in amperes (amp). Voltage, V, is measured in volts (V). Calculating the conductance is easy—it is the current divided by the voltage, as shown below in Equation 1. Equation 1.
G = | I
* G is conductance, measured in siemens.
* I is current, measured in amperes (amp).
* V is the voltage, measured in volts (V).
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