1. Lesson 2: Mass

2. 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

3. Metric Units Mass refers to the amount of matter in an object. The base unit of mass in the metric system in the kilogram and is represented by kg. Standard: 1 kilogram is equal to the mass of the International Prototype Kilogram (IPK), a platinum-iridium cylinder kept by the BIPM at Sèvres, France. 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 Kilogram Prototype Kilogram Prototype Image - http://en.wikipedia.org/wiki/Kilogram

4. Measuring Mass We will be using a digital balance to find the mass of various objects. First, the balance is turned on. Second, set the balance to measure mass in grams (g). Third, place the object on the platform and wait for a digital reading. Measuring the mass of a liquid: Use a container to hold the liquid. TARE the mass of the container in order to obtain the mass of the liquid only. Measuring the mass of chemicals or other substances that are in granular form: Use a piece of paper to protect the platform. TARE the mass of the paper in order to obtain the mass of the chemical only.

5. Measuring Mass – valuable feature called TARE Container Example: Place your container (i.e. box, bowl, cup, etc.) on the balance's platform that will hold the item(s), then push the TARE button. Your balance's display will reset to 0 by subtracting the weight of the container. Then simply place the item(s) in the container and your scale will display the actual weight of the item(s) in the container. TARE is a feature that simply removes the weight of an item placed on the platform. There may be two different time you may choose to use this feature. Platform Example: If you need to weigh an item that will not stay on your blance's platform, you can increase the platform size by placing a flat item - such as a piece of plywood - that is larger than the platform and pushing the TARE button. This will remove the weight of the plywood and you will now have a larger weighing platform.

6. Follow instructions as they are listed in the handout “Mass Lab”. If you do not finish the activities in class, please complete them at home. Measuring Mass Activity