Which instrument is used to measure mass with sliding weights on three beams?

• A. Triple beam balance
• B. Graduated cylinder
• C. Thermometer
• D. Ruler

Answer: (A)

To measure mass precisely, you use a balance that compares the object to known standard weights using sliding weights on multiple beams. The instrument with three beams is built exactly for this purpose. You place the object on the pan and slide the weights along the three beams until the balance is level. Each beam contributes a place value (hundreds, tens, and ones of grams), so you read the numbers on all three beams and add them to get the mass in grams. This setup is specifically designed to measure how much matter an object has by balancing against known masses.

The other tools measure different properties: a graduated cylinder is for volume of liquids, a thermometer for temperature, and a ruler for length. That’s why they don’t fit the task of measuring mass.