Hydrometer Callibration

We, myself, Todd at the High School, and his science class, calibrated my Hydrometers by weighing out a measured volume of Battery Acid, and dividing the mass in grams by the volume in milliliters. We measured 25 ml in this, and got the weight.

Of the four hydrometers, two were defective. A plastic one had a fine crack in the back, and a glass one has fluid in the float. The specific gravity reading is affected how it is done: the battery acid must not go into the bulb, and the rubber tip must stay submerged in the acid while the reading is being done. Then, both the plastic and glass hydrometers gave the same readings.

I had bent a glass hydrometer to be able to read it better, and broke the thermometer hear the tip. A light on a bill cap seems to work best, if there can't be a light in the battery room that will throw a spark and ignite battery room gasses.

Now to measure the specific gravities, and decide which batteries to discard.