VictoriaBoRyung

toc =__**Designing Experiments - Part II**__=

__**A. Introduction:**__
//The independent variable// //(th]e variable we are changing)// - Size of electrode (metal) //Dependent variables (constant variables)// - Temperature Concentration Amount of salt water Size of the cup

//The importance of **constants** and **simplicity** in a **controlled** experiment// - Constants are important because if there are too many unknown variables, it will be hard to find the correct result. Simplicity is also important because if there are too many variables, it will cause confusions while doing the experiment.

//Expectations// - The bigger the electrodes are, the larger the voltages and currents will be shown. It is because a bigger electrodes would //conduct// more electricity (copper is a good electricity conductor).

//**What we did and what we discovered:**// We changed the size of the copper, while still keeping the aluminium piece the same. We measured the voltage and current, and got mostly the expected result

__**B. Materials**__:
5 coppers of different sizes. One aluminium One beaker Salt water with known density Scale Voltmeter

__**C. Procedure:**__

 * 1.** Fill a beaker with salt water to 400ml
 * 2.** Place the //aluminium// into the beaker
 * 3.** Weigh the coppers with the scale
 * 4.** Put one of the coppers into the beaker, making sure they do not touch.
 * 5.** Measure the voltage and current, and take down the data.
 * 6.** Repeat steps **1-5** for the other coppers

__**Mass of coppers -**__

 * 1 :** 2.86g
 * 2 :** 5.23g
 * 3 :** 15.08g
 * 4 :** 17.32g
 * 5 :** 19.52

__**D. Result :**__

 * < **Copper** ||> **1** ||> **2** ||> **3** ||> **4** ||> **5** ||
 * < **Mass** ||> 2.86g ||> 5.23g ||> 15.08g ||> 17.37g ||> 19.52g ||
 * < **Voltage (V)** ||> 0.258~0.270 ||> 0.317 ||> 0.380~0.320 ||> 0.510~0.420 ||> 0.50~0.400 ||
 * < **Current (A)** ||> 0.940~0.950 ||> 2.3 ||> 5.5 ||> 6.6 ||> 10.3~3.5 ||

__**Graph** (using average voltage/current)**:**__
Mass (grams)

__**E. Evaluation of Results:**__
The data seems to be what we expected, except for maybe one of the numbers for voltage, although it is very close. To make this experiment even more precise, when the voltage or current were taken down, the same amount of time should be taken. The strength of this experiment was that the metals were completely submersed in water, which lessens uncertainty. The results are what was to be predicted, and showed that larger metals do mean more voltage and power. This would mean that an efficient battery would have suitably large metals inside.