Measurements

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Jeremy wants to see if the amount of Wheaties he eats in the morning affects the number of points he makes in that day’s basketball game. While he changes the amount of Wheaties, he keeps using the same amount of milk.

Amount of Wheaties

Independent Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Jeremy wants to see if the amount of Wheaties he eats in the morning affects the number of points he makes in that day’s basketball game. While he changes the amount of Wheaties, he keeps using the same amount of milk.

Number of points

Dependent Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Jeremy wants to see if the amount of Wheaties he eats in the morning affects the number of points he makes in that day’s basketball game. While he changes the amount of Wheaties, he keeps using the same amount of milk.

Amount of Milk

Control Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Christina wants to test whether the “smart pills” she recently ordered from the internet will actually improve her grades. She tries to keep the rest of her diet the same.

Her grades

Dependent Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Christina wants to test whether the “smart pills” she recently ordered from the internet will actually improve her grades. She tries to keep the rest of her diet the same.

Smart pills

Independent Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Christina wants to test whether the “smart pills” she recently ordered from the internet will actually improve her grades. She tries to keep the rest of her diet the same.

Rest of her diet

Control Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Julia wants to see if the amount of water she gives her plant will affect its growth. She keeps the amount of sunlight the plant receives constant.

The plant’s growth

Dependent variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

Julia wants to see if the amount of water she gives her plant will affect its growth. She keeps the amount of sunlight the plant receives constant.

Amount of sunlight

Control Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

University researchers are studying whether or not a student has breakfast every day affects his/her state test scores. During the study, they keep the number of students they are studying the same.

The number of students

Control Variable

But First - ReviewFor each of the following experiments, state whether

the variable mentioned is the independent variable, dependent variable, or control variable.

University researchers are studying whether or not a student has breakfast every day affects his/her state test scores. During the study, they keep the number of students they are studying the same.

Whether a student has breakfast

Independent Variable

What is a Measurement?Measurement – describes a physical

quantity with a number AND a unit

Common MeasurementsQuantityWhat it measures

Metric

UnitTool used to measure it

Length

A distance

Meters (m)

Meter stick, ruler

Mass

How much matter there isGrams (g)

Balance

VolumeAmount of space taken up by matterLiters (L)

Graduated Cylinder

Measuring Mass1. Put weighing

container on balance.

2. Zero the balance.3. Fill container with

matter.4. Read balance. Do

NOT round.

Measuring Volume1. At eye level, look at

the surface level of the liquid.

2. Measure at the bottom of the meniscus, or curve.

3. Watch the lines! (Be careful when figuring out how many mL each line represents!)

Each line in this graduated cylinder is 1 mL

Measuring Volume1. At eye level, look at

the surface level of the liquid.

2. Measure at the bottom of the meniscus, or curve.

3. Watch the lines! (Be careful when figuring out how many mL each line represents!)

Each line in this graduated cylinder is 0.2 mL

Accuracy, Precision, Percent ErrorAccuracy – how close a measurement is to

the actual value

Precision – how exact your measuring tool is(usually has more numbers)

Accuracy, Precision, Percent ErrorPercent Error – shows how accurate a

measurement isSmaller Percent Error = More Accurate

Example 1

Which trial has the most EXACT measurement?

Trial 3 is the most precise

Which trial has the smallest percent error?Trial 2 is the most accurate

Example 2The actual volume of a 2 Liter bottle of soda is 2

L. However, when I measure the amount of liquid inside, I measure 1.9L. What is my percent error?

Actual Value: 2LYour Value: 1.9L

Measurements Activity

Read all directions CAREFULLY!!

Measurements Independent Practice

Let me know if you have any questions!!

Unit 1 Vocabulary ReviewHypothesis Theory Law

Independent Variable Dependent Variable

Control Variable Model

Quantitative Data Qualitative Data

Graduated Cylinder Balance

Grams (g) Meters (m) Liters (L)

Accuracy Precision Percent Error