I am not exaggerating when I say that knowing my units of measurement and conversion factors literally saved my life. 

A few years back, we were living in a foreign country and my appendix flared up. Long story short, it had to be removed . . . quickly. There was no time to weigh me beforehand, so the anesthesiologist asked me how much I weighed. 

And I gave my answer in pounds . . . only they didn't use pounds in that particular country.  They used the metric system, which meant that my weight should be given in kilograms. 

The doctor replied that there was no way I weighed that much. This time she asked, "What is your weight in kilos?"

Uhhhh . . . 

And that's when my high school chemistry teacher flashed into my mind's eye - 1 kilo equals 2.2 pounds.

I did a bit of quick math in my head and answered her question.  Luckily my math was right, the anesthesiologist was able to give me the right dose for surgery, and I'm here today partly because I knew how to convert pounds to kilograms in a moment.

Now, I know that my story is a bit dramatic and not all of your students will be in a foreign country needing to convert their weight in an emergency situation. But units of measurement and knowing how to convert them is super important to science.

So, I wanted to take a moment to share a bit more about units, along with some of the key conversion factors your students should memorize. And, then we'll wrap it all up with a free printable you can use with your students to practice all this.

Sound good? Let's dig in!

Why are the units of measurement so important?

I am a bit of a stickler on units of measurement thanks to my high school chemistry teacher. She always told us that a number in chemistry meant nothing without its units, which is so true.

After all, if I say that I need 2 of sugar for a recipe, do you know if I mean 2 tablespoons, 2 grams, 2 cups or 2 kilos?

That’s why from the very first time I introduce measurements to my students I always emphasize the importance of not forgetting to write the units. I know from experience how key it is to lay a foundation for remembering these units of measurement early on.

Knowing the units of measurement that correspond with a number can give you so much more information than a digit sitting there by itself. Units can:

• Help to show another person the exact amount you have
• Assist in solving a mathematical problem, especially in chemistry, where you can follow the units to get to the answer
• Show which measurement system the person is using (i.e. metric or standard)

In a nutshell, the unit of measurement in science serves as the supporting pillar upon which a number rests.

What are the two main systems of measurement?

There are two main systems of measurement used in today’s nations:

1. The Metric System – This system is used in most of the world and it employs units like meters, grams, and liters. The system is base 10 and the names are formed with prefixes. It was derived from one of the early French measuring systems.
2. The Standard or Standard American Engineering (SAE) System – This system is mainly utilized in the United States and it contains units like inches, pounds, and gallons. It was derived from an early English measuring system that has its roots in the Roman system of measurements.

In the US, the SAE system of units is more widely used on consumer products and in industrial manufacturing, while the metric system is more widely used in science, medicine, and government.

So, it’s especially important for American students to be familiar with both systems.  Even so, every student should know how to convert measurements inside of their most commonly used system of measurement. In other words, students should be familiar with knowing how to convert grams to kilograms or ounces to pounds.  

Key Conversion Factors to Know

Normally, these conversion factors are taught as a part of their math program.  But, I also recommend that have your students memorize several basic conversion factors between the two systems as part of their science plan.

Here’s what every student should know:

• Pounds to Kilograms: 1 kg = 2.2 lb
• Gallons to Liters: 1 gal = 3.785 L
• Feet to Meters: 1 foot = 0.305 m
• Miles to Kilometers: 1 mi = 1.61 km
• Cups to Milliliters: 1 c = 240 mL
• Inches to Centimeters: 1 in = 2.54 cm
• Ounces to Grams: 1 oz = 28.3 g

With the global flow of information that occurs these days, it is very important for students to learn these most basic conversion factors.

Wrapping it up {Free Printable}

Want a free set of worksheets to practice these conversions along with a conversion factor cheat sheet? Here you go:

• Units of Measurement Worksheet Packet