To measure the density of an object, you need to determine its mass and volume, then use the formula for density. Density is the mass of an object per unit volume, typically expressed in grams per cubic centimeter (g/cm³) or kilograms per cubic meter (kg/m³).
Steps to Measure Density
- Measure the Mass:
- Use a digital or balance scale to measure the object's mass in grams (g) or kilograms (kg).
- Ensure the scale is calibrated and the object is clean and dry for accuracy.
- Record the mass.
- Measure the Volume: The method to measure volume depends on the object's shape and properties:
- Regular Shapes (e.g., cube, cylinder, sphere):
- Measure dimensions (length, width, height, radius) using a ruler, caliper, or measuring tape.
- Calculate volume using the appropriate geometric formula:
- Cube: V = side³
- Rectangular prism: V = length × width × height
- Cylinder: V = π × radius² × height
- Sphere: V = (4/3) × π × radius³
- Irregular Shapes:
- Use the water displacement method:
- Fill a graduated cylinder or container with a known volume of water.
- Submerge the object completely and measure the new water level.
- The difference in water levels is the object's volume (in cm³ or mL; 1 mL = 1 cm³).
- Ensure the object is fully submerged and no air bubbles are trapped.
- Use the water displacement method:
- For objects that float, gently push them under the water using a thin, massless tool.
- Regular Shapes (e.g., cube, cylinder, sphere):
- Calculate Density:
- Plug the mass and volume into the density formula: ρ = m / V.
- Ensure units are consistent (e.g., mass in grams and volume in cm³ for g/cm³).
- Perform the calculation and round to an appropriate number of significant figures.
