Density is the mass of an object per unit volume (ie the space occupied by this object). The unit of density is grams per milliliter (g / ml). Finding the density of water is relatively simple and is done using the formula density = mass / volume.
Part 1 of 2: find the density of water
Step 1. Gather the necessary materials
To calculate the density of water (density), you need a graduated cylinder, a scale, and water. Graduated cylinders are special vessels with lines or graduations drawn on them that allow you to measure a specific volume of liquid.
Step 2. Weigh the empty graduated cylinder
In order to find the density, you must first know the mass and volume of the liquid in question. You will use the graduated cylinder to get the mass of the water, but you will need to subtract the mass of the graduated cylinder from the total mass.
- Turn on the scale and verify that it is set to zero.
- Place the dry, empty graduated cylinder on the scale.
- Record the mass of the cylinder in grams (g).
- For example, imagine that the empty graduated cylinder weighs 11 grams.
Step 3. Fill the graduated cylinder with water
The amount of water does not matter. On the other hand, it is very important to note this quantity. Read the volume by placing your gaze directly in front of the water level and note the value at the bottom of the meniscus. The meniscus is the curved part of the surface of the liquid that you see when the water level is right in front of your eyes.
- The volume of water in the graduated cylinder is the one you will use for the density calculation.
- Suppose you have filled the graduated cylinder with 7.3 milliliters (ml) of water.
Step 4. Weigh the graduated cylinder filled with water
Check that the scale reads zero, and weigh the cylinder filled with water. Be careful not to spill any during the operation.
- If you spill the water, write down the new volume of water in ml and reweigh the cylinder filled with water.
- Imagine, for example, that the graduated cylinder now weighs 18.3 grams.
Step 5. Subtract the mass of the empty cylinder from the mass of the full cylinder
To get only the mass of water, you need to subtract the mass of the graduated cylinder. The result represents the mass of the water present in the graduated cylinder.
In our example, the mass of the graduated cylinder is 11 g while that of the cylinder is 18.3 g. So, 18.3 g - 11 g = 7.3 g. The water weighs 7.3 grams
Step 6. Calculate the density
To do this, divide the mass by the volume. To determine the density of water, use the following equation: density = mass / volume. Enter the mass and volume you determined into the equation and find the value for the density.
- Mass of water: 7.3 g
- Water volume: 7.3ml
- Water density = 7, 3/7, 3 = 1 g / ml
Part 2 of 2: Understanding the Concept of Density
Step 1. Define the density equation
The density is equal to the mass m of an object divided by the volume v of the same object. Density is represented by the Greek letter rho: ρ. A denser object will have a greater mass for a smaller volume compared to an object of less density.
The standard equation for density is: ρ = m / v
Step 2. Use the correct units for each variable
When calculating a density, it is customary to indicate the units of measurement. The mass of an object is given in grams while the volume is given in milliliters. You can also see volumes in square centimeters (cm3).
Step 3. Know why density is an important concept
The density of an object can be used to identify different materials. If you are trying to identify a substance, you can calculate its density and compare it to materials of known densities.
Step 4. Understand what factors can influence the density of water
Although this is on the whole close to 1 g / ml, it is necessary to obtain greater precision for certain scientific disciplines. The density of pure water is altered by temperature. This increased as the temperature dropped.