This is the PowerPoint over our Nature of Science and Technology Book, Chapter 2, Section 1

1. Measurement – A Common Language Chapter 2, Section 1 – The Nature of Science and Technology

2. A Standard Measurement System The Metric System A system of measurement based on the number 10 The International System of Units (SI) Using SI allows scientists to compare data and communicate with each other about their results

3. LENGTH The basic unit of length in the SI system is the meter To measure objects smaller than a meter scientists use units called the centimeter (cm) or the millimeter (mm) Large distances are measured using kilometers (km) To measure length we use a metric ruler

4. MASS The basic unit of mass in the SI system is the kilogram (kg) To measure the mass of smaller objects we use the gram (g) Even smaller masses are measured in milligrams (mg) To measure mass we use a balance

5. MASS VS. WEIGHT… Weight is the force of gravity acting on an object. This CAN change Mass is the measure of the amount of matter an object contains. This ALWAYS stays the same!!

6. VOLUME The amount of space an object takes up To measure the volume of liquid scientists use the liter (L) Smaller volumes are measured using milliliters (mL)

7. Volume of Liquids To measure the volume of liquid just pour it into a container with markings that show the volume Be sure you read the volume at the BOTTOM of the meniscus (the curved upper surface of a liquid in a column of liquid)

8. Volume of Rectangular Solids To measure the volume of solid we use the cubic centimeter (cm3) Larger volumes can be measured using the cubic meter (m3) Calculate the volume using the formula: Volume=Length X Width X Height (or V=LWH)

9. Volume of Irregular Solids To measure the volume of solid such as rock we can immerse the object in water and measure how much the water rises

10. Density Density is the measure of how much mass is contained in a given volume To calculate density divide the mass of the object by it’s volume (D=M/V) Density is always expressed using TWO units such as grams per cubic centimeter (g/cm3), or grams per milliliter (g/mL)

11. Time The SI unit of time is the second The second can be divided, just as other units can (example, millisecond=one-thousandth of a second Longer times are measured in minutes or hours

12. Temperature Scientist commonly use the Celsius scale On this scale water freezes at 0oC and boils at 100oC Scientist may also use the OFFICIAL SI unit, Kelvin (K) On Kelvin water freezes at 273oK and boils at 373oK Measure temperature using a thermometer