Mass refers to the amount of matter (stuff) in an object. Matter: The material that all objects and substances are made up of Anything that has mass and takes up space is matter The base unit of mass in the metric system in the gram and is represented by g. Metric Units 1 Kilogram (km) = 1000 Grams (g) 1 Gram (g) = 1000 Milligrams (mg) Which is larger? A. 1 kilogram or 1500 grams B. 1200 milligrams or 1 gram C. 12 milligrams or 12 kilograms D. 4 kilograms or 4500 grams Click the image to watch a short video about mass. Kilogram Prototype Kilogram Prototype Image - http://en.wikipedia.org/wiki/Kilogram
English vs. Metric Units Which is larger? 1. 1 Pound or 100 Grams 2. 1 Kilogram or 1 Pound 3. 1 Ounce or 1000 Milligrams 1 pound = 453.6 grams 100 kilogram = 220 pounds 1 ounce of gold = 28,349.5 milligrams
How would your weight differ if you were to travel to the moon? If you were to travel to the moon your weight would be less. Your weight would be lesser because the force of gravity is less. Weight is a factor of the force of gravity acting on an object. The Difference Between Mass and Weight
Why would your mass stay constant if you were to travel to the moon? Your mass would stay the same if you were to travel to the moon because mass is the amount of matter that an object contains Since you are still made up of the same amount of “stuff”, your mass would not change The Difference Between Mass and Weight
Why do scientists prefer to use the mass of an object instead of its weight? Scientists prefer to use an objects mass instead of its weight because mass does not change when the force of gravity does The Difference Between Mass and Weight
Smaller objects such as a paper clip would be measured in milligrams. Larger objects such as a cat would be measured in kilograms. Metric Units
What are three objects (other than in the book) whose masses would be measured in kilograms. Car Teacher’s Desk Desk Top Computer Metric Units
How does a triple-beam balance work? A triple-beam balance works by comparing the mass of the object you are measuring to a known mass When you use a triple-beam balance, you: 1.Place the object on the pan 2.Shift the riders on the beams until them balance the mass of the object Start with the large rider (increments of 100) Next, the medium sized rider (increments of 10) Lastly, the small rider (increments of 1) Measuring Mass
Top Image: http://www.southwestscales.com/Ohaus_Triple_Beam_750-SO.jpg Bottom Image: http://www.regentsprep.org/Regents/biology/units/laboratory/graphics/triplebeambalance.jpg We will be using triple-beam balances to find the mass of various objects. The objects are placed on the pan and then you move the riders on the beams until you get the lines on the right-side of the balance to match up. Once you have balanced the arms(beams), you add up the amounts on each beam to find the total mass. What would be the mass of the object measured in the picture? _______ + ______ + _______ = ________ g
Measuring Mass – Triple-Beam Balance Click here to try an online activity. 1 st – Place the film canister on the pan. 2 nd – Slide the large riders to the right until the arm drops below the line. Move the rider back one groove. Make sure it “locks” into place. 3 rd – Repeat this process with the top rider. When the arm moves below the line, back it up one groove. 4 th – Slide the small rider on the front beam until the lines match up. 5 th – Add the amounts on each beam to find the total mass to the nearest tenth of a gram.
Label the different parts of the triple-beam balance.