2. Metric System (System International or SI) The metric system is used in science so that the entire world will be using the same system. It is based on the number 10. Units of measurement: Mass = Gram (g) Volume = Liters (l) Length = Meter (m) Density = Grams per milliliter (g/ml) Temperature = Celsius (c) or Kelvin (k) Force = Newtons (n)

3. Metric prefixes Prefixes can be added to any unit whenever larger or smaller measurements are needed: milli (m)- one one-thousandth; 0.001 centi (c)- one one-hundredth; 0.01 Deci (d)- one tenth; 0.1 Base Unit (Ex.= Gram, Liter, Meter)– one; 1 deka (da)- ten; 10 hecto (h)- one hundred; 100 kilo (k) - one thousand; 1,000... and a few you might want to know …  nano (n) = 1 one-billionth = 0.000000001  micro (µ) - one one-millionth; 0.000001  mega (M)- one million; 1,000,000  giga (G)- one billion; 1,000,000,000

4. Metric Conversions In order to convert larger or smaller metric units you must count the steps of the metric prefixes and then move the decimal point to the left when going down the steps and right when going up the steps: Step 1= Milli Step 2= centi Step 3= deci Step 4= Unit (g, m, l)) Step 5= deka Step 6= hecto Step 7= kilo Move decimal to the left Move decimal to the right

5. Examples: You need to convert 2.5 Meters into centimeters. There are you take two steps up from meters to get to centimeters. 2.5000 M = 250.00 cm Step 1= Milli Step 2=centi Step 3= deci Step 4= Unit (M) Step 5= deka Step 6= hecto Step 7 kilo

6. Practice: Change the following: 1. 25000 liters into Kiloliters 2. 450 millimeters into meters 3. 4,500,000 centigrams into Kilograms 4. 195 centimeters into meters 5. 5 Kilometers into meters 6. 15 Kiloliters into milliliters Step 1= Milli Step 2=centi Step 3= deci Step 4= Unit (M) Step 5= deka Step 6= hecto Step 7kilo

7. Mass base unit is a gram (g) Mass is the amount of matter in an object. It is measured in grams with a balance. A triple beam balance uses known masses, and balances them with unknown masses. Can you tell what the mass of the object on this balance is?

8. Volume Base Unit is a Liter (l) Volume is the measurement of how much space an object takes up, in other words its size. Volume is measured in liters with tools such as a graduated cylinder. Menisc us 142 ml

9. Length Base Unit is a Meter (m) The base unit of length in the metric system is the meter. A meter is just a little longer than a yard (39.5 inches).

10. Temperature Unit of measurement is Celsius Temperature is measured in degrees Celsius in the metric system. The Celsius scale is based on the boiling and freezing points of water at sea level. Water freezes at 0 ° and boils at 100 °.

11. Density Measured in grams per milliliter (liquids) or grams per centimeters cubed (solids) The amount of mass in a given volume is density. Elements are measured in grams per milliliter (or grams per centimeters cubed). Water has a density of 1 g/ml. If a substance has a higher density it sinks, and if it has a lower density it floats. SubstanceDensity (g/cm 3 ) Air0.0013 Wood (Oak)0.6 - 0.9 Ice 0.92 Water 1.00 Bricks 1.84 Aluminum 2.70 Quartzite2.70 Steel 7.80 Silver 10.50 Gold 19.30

12. Force Base Unit is a Newton (n) Weight is a measurement of the pull of gravity (a force). on an objects mass The greater the gravitational pull the higher the weight. That is why a person weighs more on earth than they would on the moon. The metric unit for force is a newton. 1 newton is 0.22 pounds. A spring scale is used to measured an objects weight.

13. Time The metric Unit for time is a Second. SI prefixes are commonly used to measure time less than a second, but rarely for multiples of a second. Instead, the non-SI units: 6minutes, hours, days, years, centuries, and millennia are used. Other Units minute (60 seconds) hour (60 minutes) day (24 hours) week (7 days) month (28-31 days) year (about 365.25 days)

14. The Hands of Time The long hand is the minute hand. The short hand is the hour hand.

15. The Hands of Time There are 60 minutes on a clock face. Skip count by fives to count the minutes with me. 5 15 10 2525 2020 3035 6060 55 40 45 50

16. The Hands of Time Count the numerals on the clock. There are only 12 hours on a clock face. So, the hour hand is a short hand.

17. . “Minute” is a long word. The minute hand is the longer hand. “Hour” is a short word. The hour hand is the shorter hand. hour

18. When the minute hand is pointing to 12, read the time as “o’clock”. In this case, the hour hand is pointing to the 3 and it is “three o’clock”.

19. Now the minute hand is pointing to 12 and the hour hand is pointing to the 5. So, we read the time as “five o’clock”.

20. Four Quarters If we were to slice the clock into 4 equal sections, we would have 4 QUARTERS. Each quarter would represent a 15 minute section.

21. A Quarter After When the minute hand is pointing to the numeral 3, we say that the time is “A quarter after/past _____.” Here, the clock shows a quarter past seven, or 7:15.

22. A Quarter Til/To When the minute hand is pointing to the numeral 9, we say that the time is “A quarter til/to _____.” Here, the clock shows a quarter to five, or 4:45.

23. Half Past When the minute hand is pointing to the numeral 6, we say that the time is “Half past _____.” Here, the clock shows half past 2, or 2:30. Notice how the hour hand is half-way in between the 2 and the 3.

24. AM/PM 12:00 AM is MIDNIGHT (We are sleeping) 12:00 PM is NOON (lunchtime) When we say AM, we are referring to the hours before NOON. When we say PM, we are referring to the hours past NOON.

25. Important Facts About Time 60 seconds= 1 minute 60 minutes= 1 hour 24 hours= 1 day 30 minutes= 1 half hour 15 minutes= 1 quarter hour