MEASURING MASS

1. MEASURING MASS With a triple-beam balance All images courtesy of Google Images and are under Creative Commons Licensing

2. What is mass? The amount of matter in an object. All images courtesy of Google Images and are under Creative Commons Licensing

3. Measuring mass In this lesson, we will be measuring the mass of solids with a triple-beam balance. Triple-beam balance All images courtesy of Google Images and are under Creative Commons Licensing

4. Metric units & Measuring mass The triple-beam balances we will use today will measure in grams (G), which are metric units. The balance is called a “triple-beam” because of the 3 beams which carry weight poises. The middle beam reads only in 100 g increments. The far beam reads only in 10 g increments. The weights in these 2 beams must always sit in a "notch". They cannot just be placed at any point on the beam. The weight on the front beam can be placed to read continuously from 0 to 10 grams. 1 Kilogram (km) = 1000 Grams (g) 1 Gram (g) = 1000 Milligrams (mg) All images courtesy of Google Images and are under Creative Commons Licensing

5. Calibrating the scale Before measuring an object you must first calibrate the scale. Doing so will ensure that the balance will read the most accurate measurement possible. Calibrate the scale by sliding all three weight poises (the metal brackets that slide along the three beams) to their leftmost positions. Twist the adjustment knob until the balance pointer lines up with the fixed zero mark. All images courtesy of Google Images and are under Creative Commons Licensing

6. Measuring mass To measure a solid, you first place it on the measurement tray. Then you move each of the weight poises on the 3 beams until the weight on the beams brings the pointer back to the zero mark. Now you know that you’ve balanced the scale for the solid being measured and you can record your measurement. All images courtesy of Google Images and are under Creative Commons Licensing

7. Recording your measurement To record your measurement, you will add the grams from each weight poise to determine the total mass of the object you are measuring. Let’s look at these beams and where their weight poises are sitting. What would the total mass be for this measurement? _____ + ______ + ______ = ______ 300 70 3.5 373.5 g All images courtesy of Google Images and are under Creative Commons Licensing

8. Measuring mass Now we will practice measuring the mass of various solid objects. Draw the following chart in your science journal. Measure the mass of each canister on the triple-beam balance. Be sure to add the 3 beam’s weight poises to find the total mass of each canister. Now order the canisters from the least amount of mass to the most in your science journals. All images courtesy of Google Images and are under Creative Commons Licensing

9. Let’s review… 1. What is mass? The amount of matter in an object. 2. What metric unit did we measure with? grams. 3. How do you find the total mass of what you’ve measured? Add the amount from all 3 beams. 4. What should you do to the triple-beam balance before measuring the mass of an object? Calibrate the scale.