Metric System Conversions

Metric System/Conversions ➔ The metric system is an international decimal system that is used in almost all countries. ◆ It is used in scientific and technical fields ➔ The United States, unlike many other countries, uses the customary system ➔ The metric system is based on 10s ◆ Units become bigger or smaller based on the power of 10 ➔ Units such as the meter (length), liter (volume), and gram (mass) are used ◆ Prefixes can be added to these base units to change their values ● For example, kilometer means 1,000 meters ● “Kilo-” means 1,000 & “meter” stays ● Thus, 1 kilometer = 1,000 meters ➔ Since the metric system is based on 10s, there is an easy way to convert metric units. ◆ Remember the sentence “King Henry Died By Drinking Chocolate Milk” Kilo Hecto 1,000 100 Deka base unit Deci 1 0.1 10 Centi 0.01 Milli 0.001 ➔ Note: the base units include meter, gram, liter, etc ➔ Using this diagram, you can see how each unit is related to each other. ◆ “Kilo” is 1,000 times larger than the base unit ● Thus, 1 kilogram is 1,000 times larger than 1 gram, so there are 1,000 grams in a kilogram ● There are also 1,000 meters in 1 kilometer ◆ “Milli” is 1,000 times less than the base unit ● 1 gram has 1,000 milligrams ➔ To convert in the metric system, you simply have to move the decimal point. For example, if you do not know that there are 1,000 grams in 1 kilogram, you can figure it out by looking at the chart above ➔ Let’s solve the following question: 1 kilogram = ____ grams ◆ First, locate where the prefix of the unit you are given is in the picture. We are given “1 kilogram,” so we need to look for “kilo” Kilo Hecto 1,000 100 Deka base unit Deci 1 0.1 10 Centi 0.01 Milli 0.001 ◆ Above, “kilo” is highlighted. Now, we have to move from this highlighted area to the unit we are looking for ● We are trying to find the amount of grams, which is a base unit ● Therefore, we must move the decimal point to the right until we react the base unit area ● Count how many times you need to move the decimal Kilo Hecto 1,000 100 Deka 10 base unit Deci 1 0.1 Centi 0.01 Milli 0.001 ➔ As you can see, we moved to the right three times from “kilo” to reach the “base unit.” Therefore, we must move the decimal point to the right three times to find the number of grams in 1 kilogram ◆ 1 kilogram = 1.000 kilogram ◆ If you move the decimal point to the right 3 times, you get 1,000 ◆ Therefore, 1 kilogram = 1,000 grams ➔ 4 millimeters = ___ centimeters ◆ First, locate millimeters since it is the number we are given. Notice that centimeters is to its left, so we will be moving left this time. To reach “centi” from “milli,” you only need to move left once ◆ Therefore, we are moving the decimal point one time to the left ◆ If you move the decimal point in 4 (4.0) once to the left, you get 0.4 ◆ Thus, 4 millimeters = 0.4 centimeters ➔ If you remember the sentence “King Henry Died By Drinking Chocolate Milk,” you will remember the order of the units (K H D B D C M), and you can then convert between the metric system ➔ It is normal for people in the United States to use the customary system. So, they are used to saying their height and lengths of other objects using inches, feet, yards, miles, etc. ➔ However, it is also important to be able to identify the appropriate units used for specific objects ➔ For example, you would say an apple is 8 centimeters long, not 8 meters long. Meters is not the appropriate unit for a small object like an apple, as it is too large. ➔ When measuring height, Americans likely use feet. If we were using the metric unit instead, we would measure in centimeters. Meters are slightly too big for measuring height, and millimeters are too small. ➔ Knowing that I mile = 1,609 meters (about), how many meters are in 4 miles? ◆ You can set up proportions to solve ◆ Then, you can cross-multiply ◆ In this example, we are converting between customary and metric 1 mile 1,609 meters = 4 miles x meters x = 6,436, so there are about 6,436 meters in 4 miles