Measuring Mass & Weight (Cambridge (CIE) O Level Physics): Revision Note

Measuring Mass & Weight

Measuring the Mass of an Object with a Digital Balance

Using a Digital Balance to Measure the Mass of an object

The digital balance must read zero before the object is added, then wait until the reading has settled before taking the measurement

1. Turn on the digital balance by pressing the power button

2. Wait for the value on the display to show zero (if it does not settle on zero, press and hold the zero button)

3. Place the object on the digital balance

4. Wait for the reading to stop fluctuating

5. Record the measurement 

6. Remove the object and wait for the display to read zero again before placing another object on the balance

Measuring the Mass of a Substance - Zero Method

Using The Zero Method to Measure the Mass of a Substance

The empty container is placed on the digital scale and then the scale is zeroed so that the mass of the container is not included in the measurement

1. Turn on the digital balance by pressing the power button

2. Wait for the value on the display to show zero

3. Place the empty container on the digital balance

4. Wait for the reading to stop fluctuating

5. Hold the zero button (sometimes called the tare button) until the display reads zero

6. Add the substance to the container

7. Wait for the reading to stop fluctuating

8. Record the measurement 

9. Remove the container and wait for the display to read zero again before placing another object on the balance

Measuring the Mass of a Substance - Subtraction Method

Using The Subtraction Method to Determine the Mass of a Substance

The mass of the empty container is recorded and then subtracted from the combined mass of the container and the substance

1. Turn on the digital balance by pressing the power button

2. Wait for the value on the display to show zero

3. Place the empty container on the digital balance

4. Wait for the reading to stop fluctuating

5. Record the measurement of the container only

6. Remove the container and wait for the display to read zero again

7. Place the container with the substance inside on the digital balance

8. Wait for the reading to stop fluctuating

9. Record the measurement of the substance + container

10. Subtract the mass of the container only from the mass of the substance + container

    

Measuring Weight Using a Force Meter

Using a Force Meter to Measure the Weight of an Object

The object is suspended from the force meter to give a reading of the object's weight. The reading should be taken from eye level to avoid parallax error

1. Hook the object onto the newton meter or force meter (these are two different names for the same device)

2. Carefully raise the object and newton meter so that the object is freely hanging

3. Wait for the object for still and for the reading to steady

4. Take the reading from eye level to ensure accuracy

• Mass can also be determined using this measurement of weight

  • W = mg

  • Therefore,