Obtaining the temperature of a puddle of water can be done with a standard thermometer, but one graduated for fractions of a degree gives more accurate readings. The temperature of the puddle varies depending on where the thermometer is inserted, as deeper levels of water near the center are likely to be colder at the bottom. Edges of the puddle heat up faster from heat in the surrounding air and the warming effect of sunlight. To obtain an average temperature, measurements should be taken from several different points in the puddle within a short period of time. Ten or 20 different readings added together, then divided by the number of readings taken, gives a good estimate of the temperature for the entire puddle.
Determining the surface area of an irregular shape like a puddle is not too difficult but it is only an approximation. Since a puddle generally has a circular shape, a piece of long string can be used to mark off the largest region of the puddle that looks like a circle. Measuring the length from the center of this circle to the outer edge gives the radius. Multiply the radius times itself, then multiply that number by the figure of Pi, which is approximately 3.142. If the radius was measured in inches, this results in an area of inches squared. Repeat the process for any smaller regions of puddle outside the main circle by marking them off as smaller circles, and add their surface area to the larger one for a good approximation of the total surface area.
To calculate the volume of the puddle, the surface area is used as part of the process. Since volume is a three-dimensional number, it is necessary to determine the average depth of the puddle. This is similar to what was done with the thermometer, except in this case a ruler is inserted into the puddle at different points, and the depth of the water is measured. After 20 measurements, add these different depths together and divide the total number by 20. This gives an average depth of the puddle. Multiply this number by the surface area, and the cubical volume of the puddle is shown. If the surface area of the puddle was 150 square inches, for instance, and the average depth is 2 inches, the volume is 300 cubic inches.
The easiest way to calculate the mass or weight of the puddle is to relocate its contents. Before this is done, an accurate scale should be obtained and a bucket big enough to hold the total amount of liquid. A large sponge for soaking up the water is also necessary. Weigh both the sponge and bucket together to get their total weight. Then remove all the water from the puddle with the sponge and place it in the bucket. Weigh the bucket, sponge and water again, and subtract the weight of the bucket and sponge from the total. This gives the total mass of the puddle in pounds or grams, depending on the scale. This is also something of an approximation, however, like the other measurements. As the water is transported, some of it evaporates into the air, so the original mass is slightly higher than the one the scale reads.