Have you ever measured tables? Which measurement tool would make the most sense? A ruler? A tape measure? Take a look at this dilemma.

The next day while the seventh graders were setting up the tables for the bake sale, Mr. Potter the custodian came to them with an idea.

“Hey kids, I think I have a bigger table for you,” he said.

“That would be great!” exclaimed Tyrone.

“Yes. I think it is larger than this one, but I’m not sure. Go to my supply closet and come back and measure this one. Then meet me in the auditorium and I’ll show you the other one. Then you can decide which one is best.”

“Okay,” Tyrone said.

Tyrone went to the supply closet and grabbed a ruler. He came back to the bake sale area to measure the table.

“What are you going to do with that?” Felix asked.

“Measure this table,” Tyrone said as Felix laughed. “What are you laughing at?”

“Your choice of tools, you should choose a tape measure.”

“Really why?” Tyrone asked looking up from the table.

**
Do you know why it makes more sense to use a tape measure verses a ruler? Tyrone isn’t sure, but Felix seems to have a clue. This section is all about measurement and measuring with tools and units. Pay attention to this Concept and at the end, you will be ready to help Tyrone understand why one tool is better than another.
**

### Guidance

**
Measurement
**

**is the system of comparing an object to a standard.**

Previously we worked with the customary system which includes units of length (feet or inches), weight or mass (ounces and pounds), and volume (cups or gallons). When we make a measurement of length, weight, or volume, we are comparing the object against a standard (1 foot, 1 ounce, 1 teaspoon).

**
Tools for customary measurements provide these standards.
**
The
**
ruler
**
is the tool for measuring length, and width. You can find short rulers that are 1 foot, or 12 inches in length, or you can find what are known as
**
yardsticks
**
, which measures 1 yard, 3 feet, or 36 inches. Another way to measure length is with a
**
measuring tape
**
, which can be uncurled to measure longer lengths. Measuring tapes usually show inches and feet.

**
The balance
**
or
**
scale
**
is the appropriate tool for measuring weight or mass in ounces and pounds.

When we are cooking, we often use a
**
measuring cup
**
to measure out portions of liquids or powders. You can find different sizes of measuring cups. The most commonly used measuring cup measures exactly 1 cup, but you can also find
cup,
cup, and
cup sizes.

Choose the appropriate tool for making the following measurements:

a) the weight of an apple

b) to measure the length of a swimming pool

c) to measure the length of a caterpillar

If you think about each item, it becomes easy to determine the best tool for each measurement.

**
The answers are:
**

a) Balance or scale

b) Yardstick or measuring tape

c) Ruler

**
We use our system of measurement to help us complete essential tasks in everyday life.
**
If you are building a house, you will have to decide how long and how wide your house will be. If you are baking a key lime pie, you will need to know how many cups of lime juice to use.

**
Using the correct units of measurement makes our lives easier. You can measure the distance from your house to Paris, France in inches, but that’s a lot of inches! That’s why we measure that distance in miles.
**

**
When you need to measure something, always consider the most reasonable unit to use before measuring. If you choose a unit that is too small, you will get a large number that is hard to keep track of. If you choose a unit that is too large, it will be more difficult to be precise in your measurement.
**

The volume of jar of jam

Think about volume. We want to measure the volume or the amount of jam in a jar. Since a jar is small, we can use ounces to measure.

**
Ounce is the answer.
**

**
A part of figuring out the unit of measurement is to use common sense. We have to think about what we are measuring, how we are measuring, and then you will be able to figure out the correct unit of measurement.
**

Choose the best tool for each measure.

#### Example A

Milk for a recipe

**
Solution: A measuring cup
**

#### Example B

A garden plot

**
Solution: A measuring tape
**

#### Example C

A bunch of bananas

**
Solution: A scale
**

Here is the original problem once again.

The next day while the seventh graders were setting up the tables for the bake sale, Mr. Potter the custodian came to them with an idea.

“Hey kids, I think I have a bigger table for you,” he said.

“That would be great!” exclaimed Tyrone.

“Yes. I think it is larger than this one, but I’m not sure. Go to my supply closet and come back and measure this one. Then meet me in the auditorium and I’ll show you the other one. Then you can decide which one is best.”

“Okay,” Tyrone said.

Tyrone went to the supply closet and grabbed a ruler. He came back to the bake sale area to measure the table.

“What are you going to do with that?” Felix asked.

“Measure this table,” Tyrone said as Felix laughed. “What are you laughing at?”

“Your choice of tools, you should choose a tape measure.”

“Really why?” Tyrone asked looking up from the table.

**
Think about what you have learned in this lesson. Now do you understand why Felix recommends that Tyrone use a tape measure?
**

**
Think about the size of a table. A table is an item that is larger than the length of a notebook or a textbook. When an item is larger than a notebook or a textbook, you should use a tape measure. While Tyrone could use a ruler, it is harder to measure it and keep track of each length of the ruler. With a tape measure, the measurement is clear and exact.
**

**
Tyrone decides to take Felix’s advice. In no time at all, he has measured the table and is off to check with Mr. Potter.
**

### Vocabulary

- Customary System
- the system of measurement used in the United States.

- Equivalence
- equal measures

- Measurement
- Comparing an object to a standard

### Guided Practice

Here is one for you to try on your own.

What tool and unit would you use to measure the height of a tree?

**
Answer
**

To measure a tree, you could use a measuring tape, and you would measure it in feet.

### Practice

Directions: Choose the appropriate tool for the following measurements.

1. The weight of a violin

2. The volume of a small amount of oregano

3. The volume of a glass of milk

4. The length of one side of your desk

5. Sugar for a cup of coffee

6. The amount of sugar needed for a cake

7. The weight of a person

Directions: Choose the appropriate unit for the following measurements.

8. The length of a football field

9. The volume of a car’s gas tank

10. The length of an insect

11. The weight of a tennis shoe

12. The distance a person runs in 1 hour

13. The amount of water in a large drum

14. The amount of water in a pool

15. The size of a child's foot