1. The Metric System 7 th Grade Science

2. Why we use the metric system: It is used by almost every other country in the world. It is based on 10, so it’s easier to convert units. English System: – 1 foot = 12 inches – 3 feet = 1 yard Metric System: – 1 meter = 100 cm – 1 kilometer = 1000 m

3. Length Used to measure distance. Basic Unit for Length: Meter (m) Tool Used: Measuring Tape or Ruler

4. Mass The amount of matter an object has. Mass is different from weight. – Gravity is a factor in weight but not mass. Basic Unit for Mass: Grams (g) Tool Used: Triple Beam Balance

5. Temperature Temperature is a measurement of the average kinetic energy of the molecules in an object or system. It is a means of determining the internal energy contained within the system. Basic Unit for Temperature: Kelvin (K) – However we will be using the unit Celsius (C). Tool Used: Thermometer

6. Time A number, as of years, days, or minutes, representing an interval. Basic Unit for Time: Second (s) Tool Used: Stopwatch

7. Volume The amount of space something takes up. Basic Unit for Volume: Liters (l) – We will be using milliliters (ml) most of the time though. Tool Used to Measured Liquids: – Graduated Cylinder – Solids can be measured with a ruler. Formula: rectangle = length X width X height Units used with this formula are m 3 or cm 3

8. Displacement 1) Fill graduated cylinder with water and record volume. 2) Add object to cylinder and record new volume. 3) Volume of object = new volume – old volume. Example: – Grad cylinder has 100mL of water. – After the object is added, the volume is 123mL. – 123mL – 100mL = 23mL (Objects Volume)