BarbieElena

Elena and Barbie- Block H

The Concentration of Salt VS the Voltage & Current

 The purpose of our lab was to see if the concentration of salt in the “pure” water, the amount of salt added, would change the reading of the voltage or later on the current.

Abstract:In our experiment, our independent variable was the amount of salt added to the water. We started off with 0 grams of salt and for each value we added 2 grams each time. We thought that the more amount of salt added, the higher the voltage was going to turn out. After our results, our hypothesis was wrong where the more amount of salt added, the higher the voltage was going to be. Maybe during our experiment, we measured the voltage and the current incorrectly or it could just be that the amount of salt doesn't affect the quality of the battery.

Dependent variables: The metal (copper and aluminum; the distance between the metal; the amount of water; the container the experiment is held in; the temperature of the water.

1st value: no salt 2nd value: 2 grams of salt 3rd value: 4 grams of salt 4th value: 6 grams of salt 5th value: 8 grams of salt and so on..


 * The 1st value will be the smallest, because it contains the least amount of salt (no salt) meaning the number of volts will be the lowest and the 5th value will be the highest for the number of volts. This means, if there is more salt added to the water, or in other words, if the water is more concentrated of sodium chloride, we would expect that the number of volts would be higher.

Step 1: Gather materials --> big beaker, aluminum, copper, voltage measurer, sodium chloride, 100 ml of water, thermometer.

Step 2: Fill the beaker with "pure" water up to 100 mL.

Step 3: In the beaker, put a piece of each metal (aluminum and copper) at the saide opposit each other.

Step 4: Without any salt (1st value), try measure the voltage and currency.

Step 5: Add on 2 grams of salt each time as you carry on and measure the voltage and currency. Record any observations

Step 6: Repeat " Step 5"

Mass of water: 418.13 grams (with beaker) Temperature of water: 18.5 +/- 0.01 Celsius Aluminum: 4.69 grams (a thin piece) Copper: 15.27 grams (a thin piece) Distance (between metals): 4.4 cm +/- 0.02

1st value: no salt --> voltage= 0.392 +/- 0.002

2nd value: 2g of salt --> voltage= 0.402 +/- 0.002

3rd value: 4g of salt --> voltage= 0.387 +/- 0.002

4th value: 6g of salt --> voltage= 0.369 +/-0.002 --> current= 0.43-0.18 Am
 * The current number decreased.

5th value: 8g of salt --> voltage (TBA) +/- 0.002

<The Data chart && Graphs <--A labeled sketch

One of the strength of our lab was that it was simple and got straight to what we were interested in knowing. But one of it’s weaknesses was that after the 4th stage we start to notice that the voltage measurements did not have much change and so we began to also measure the current of out battery. This turned out a little bit of a mess for us in the end.

Our data however did not exactly match what our expectations. Our theory was “If the water has a lower concentration of salt then the voltage measurement would be higher." Our data proved that the measurement of the voltage indeed did increase but at a unsteady rate. The currency on the other hand was increasing at a much more faster rate. During this experiment we learnt that the amount of salt added, or the concentration of salt in the water did not really affect the measurement of the voltage. But the currency rapidly increases as the amount of salt added is being doubled.