Measuring with the Metric System

Objectives for this Video Lesson You will be able to define gram and

centimeter You will be able to use the correct measuring

device to measure gram and centimeter You will be able to calculate volume by

measuring dimensions in centimeters You will be able to calculate density using

volume and mass

Think! Think!! Think!!

What are some units of measure that you know of? (inches for example)

Pause the video and list as many as you can.

Maybe you thought of a ton, a gigawatt, a light-year, or a mile.

They are all units that we use to measure things.

When we do an experiment in science, sometimes we have to collect data in the form of measurements. It’s important to know how to measure when you are doing science experiments.

We are going to be focusing on centimeters and grams.

Centimeters and grams are part of the metric system.

The metric system is a set of measurements used by scientists, regardless of the country they live in.

You might be used to measuring with inches, feet and miles, but we are the ONLY country in the world that does this! You might say we are a very stubborn country and unwilling to do what the rest of the world is already doing!

In science, ALWAYS use the metric system.

Let’s take a look at centimeters first. Rulers usually show two different sets of numbers.On this ruler, the top set of numbers shows centimeters. Look for the word cm written on the ruler.

We use centimeters to measure length, height, and width.

If you had a cube, you could use a ruler to measure its length, width and height in centimeters with a ruler.

You can use the length, width and height to calculate another important measurement: volume. Volume is a measure of the amount of space taken up by an object. In the case of the cube, we calculate the volume by multiplying the length times the width times the height of the cube.

Volume = Length X Width X Height

If the width of the cube is 4 cm, the length is 12 cm and the Height is 3 cm, what is the volume of the cube?

Pause the video here and calculate the volume of the cube. Write the answer in your notes.

The volume of the cube is 4 times 12 times 3.Volume = 4cm X 12cm X 3cmVolume = 144 cm3

The unit of measurement “cm3” is pronounced “cubic centimeters.”

Now let’s talk about grams. Grams are a way to measure the mass of an object. Mass is a measure of how much stuff is inside a particular object. We can’t use a ruler to measure an object’s mass. Instead, we use a triple beam balance.

Here’s a link to a short video that explains how to use a triple beam balance.

http://www.youtube.com/watch?feature=player_detailpage&v=jknT_OKb6yM

There’s one final measurement you should know how to calculate.

Density is how tightly matter is packed into a particular space.

To calculate Density, you divide the mass in grams by the volume in cubic centimeters.

Let’s try it:

Frank has a paper clip. It has a mass of 9g and a volume of 3cm3. What is its density?

Pause the video here to calculate the density. Write the answer in your notes.

To calculate Density, divide the mass by the volume.

Density = 9 g / 3 cm3

Density = 3 g/cm3

The units are pronounced “grams per cubic centimeter.”

Now that you know how to measure or calculate length, width, height, mass, volume and density, you are ready to practice measuring in a science experiment.

You may have to review the information about independent variable, dependent variable, control group and experimental group. You are going to use this knowledge to set up a controlled experiment and use the metric system at the same time.

Find your lab titled “Metric Mania with Gummi Bears.”

Read the entire lab so that you can get started quickly tomorrow.

Fill out only the “Hypothesis” section now.