To find density using water displacement, you need to determine the mass and volume of the object and then divide mass by volume.
Here’s a step-by-step breakdown:
Determining Mass
First, you'll need to determine the mass of the object using a scale or balance.
- Example: As shown in the reference video, a SpongeBob figure is placed on an electronic balance, and its mass is found to be 50 grams. This mass value is crucial for density calculation.
Determining Volume using Water Displacement
The next step is to determine the volume of the object using water displacement:
- Fill a graduated cylinder: Start by filling a graduated cylinder with a known amount of water, and record the initial water level.
- Submerge the object: Carefully submerge the object into the graduated cylinder.
- Record the new water level: Note the new water level after the object is fully submerged. The increase in water level represents the volume of the object.
- Calculate the volume: Subtract the initial water level from the final water level to get the volume of the object.
Calculating Density
Once you know the mass and volume, you can calculate the density:
- Formula: Density = Mass / Volume
- Example: Using the SpongeBob example; suppose the water displacement method determined the volume to be 25 cubic centimeters(cm^3). Then the density would be 50 grams / 25 cm^3 = 2 grams per cubic centimeter (g/cm^3)
Summary Table
| Step | Description | Example (Using SpongeBob) |
|---|---|---|
| 1. Measure Mass | Use a scale or balance to find the mass of the object. | SpongeBob's mass is 50 grams |
| 2. Measure Initial Volume | Fill a graduated cylinder with water and record the initial level. | Let's assume the initial water level is 50 ml |
| 3. Submerge Object | Carefully lower the object into the cylinder and note the new water level. | The water level rises to 75 ml. |
| 4. Calculate Volume | Subtract the initial water level from the final water level to find the volume of the object. Volume displaced is the volume of the object | Volume = 75 ml - 50 ml = 25 ml. Note: 1 ml = 1 cm^3, so the volume is 25 cm^3 |
| 5. Calculate Density | Divide the mass by the volume. | Density = 50 g / 25 cm^3 = 2 g/cm^3 |
By following these steps, you can effectively find the density of an object using the water displacement method. This method is particularly useful for irregularly shaped objects where direct measurements of volume would be difficult.
