Steps of Experimental Design:

M&M Investigation

Well-Defined Questions

Experimental Design:M&M Investigation

Most of the time a hypothesis is written like this: "If _____[I do this], then _____[this]_____ will happen.“

For example: “IF a plant receives fertilizer, THEN it will grow bigger than a plant that did not receive fertilizer.

Other ways to write a hypothesis: - I predict that ______________ because _______________. - I hypothesize that __________________ because______________.

Your hypothesis should be something that you can actually test.

The word HYPOTHESES is plural for hypothesis.

HYPOTHESISA hypothesis is an educated guess about how

things work.

HYPOTHESIS

Now write your own hypothesis based on the question: “Do some M&M colors dissolve faster in water than others?”

Write your hypothesis behind the “Hypothesis” tab in your foldable.

Remember: - your hypothesis needs to be in an “if”/”then” statement - your hypothesis must be testable

Examples of Possible Hypotheses

IF the M&M has a darker color, THEN it will dissolve faster.

IF the M&M has a lighter color, THEN it will dissolve faster.

MATERIALS

A materials list is important in organization and planning.

It is important to list all materials you will need in order to carry out the experiment.

MATERIALS

Behind the “Materials” tab in your foldable, list all of the materials that you will be using in the M&M Investigation lab.

Materials: White plastic plates Different colored M&Ms Water colored pencils a quarter Plastic cup, 3 ½ ounces Permanent marker Stopwatches

VARIABLES Scientists use an experiment to search for cause and

effect relationships in nature. In other words, they design an experiment so that changes to one item cause

something else to change in a predictable way.

These changing quantities are called VARIABLES.

An experiment has 3 kinds of variables:

independent (manipulated), dependent (responding) and controlled (constants)

INDEPENDENT VARIABLE

The independent variable is the one that is purposely changed or manipulated by the scientist. To ensure a fair test, a good experiment has only one independent variable. As the scientist changes the independent variable, he or she observes the changes.

Example: Does the amount of fertilizer affect plant growth? The amount of fertilizer is the independent variable because the scientist has control over how much fertilizer is used in the experiment.

Suppose that you wonder whether you can run a marathon faster when you eat pasta the night before or when you drink coffee the morning of the race. Your hunch is that loading up on pasta will give you the energy to run faster the next day. The independent variable is the consumption of pasta, and the dependent variable is how fast you run the race.

Now, if you eat several plates of spaghetti the night before you race, but then get up the next morning and drink two cups of coffee before you head to the start line, your experiment is useless.

Why is it useless? By drinking the coffee, you introduce a second independent variable, so you will not know whether the faster race time is due to the pasta or the coffee.

Experiments can have only one independent variable. If you want to know the effect of caffeine (or extra sleep or improved training) on your race time, you would have to design a second (or third or fourth) experiment.

EXPERIMENTS CAN HAVE ONLY 1 INDEPENDENT VARIABLE

What is the

independent variable

in your M&M investigation?

Independent Variable:

M&M Color

Why is M&M color the independent variable?

DEPENDENT VARIABLE

The dependent variable is what is measured in the experiment.

The scientist focuses their observations on the dependent variable to see how it responds to the change made to the independent variable.

Example:Does the amount of fertilizer affect plant growth?

The dependent variable is plant growth. This can be MEASURED, and it RESPONDS to the change made to the independent variable. (amount of fertilizer)

What is the

dependent variable

in your M&M investigation?

Dependent Variable:

how fast the M&M colors dissolve

Why is “the speed that the M&M colors dissolve” the dependent variable?

CONTROLLED VARIABLE (CONSTANTS)

When conducting an experiment, all other variables must be kept the same throughout the investigation; they should be controlled. The variables that are not changed are called controlled variables. (constants)

Example:Does the amount of fertilizer affect plant growth?

Independent variable: amount of fertilizerDependent variable: plant growth

Controlled variables: same type of plant, same pot size, same amount of water, same amount of sunlight

DATA TABLES

Tables are an excellent way to display data or information in an organized fashion.

By putting data in tables one can easily from there set up a graph to illustrate the data.

Tables have several features in common:

First, all tables as well as graphs should have a title to let the reader know the subject of the table or graph. Most tables consist of a series of rows and columns.

TITLE

ROWS

COLUMNS

GRAPHS

A graph is a chart or drawing that shows the relationship between changing things

Common graphs use bars, lines, or parts of a circle to display data.

Graphs must include a title and labels on the x and y axis.

Why will we use a bar graph in our M&M investigation?

Example of a Bar Graph

TITLE

Y-Axis

Dependent Variable

X-Axis Independent Variable

DRY MIX

DRY MIX is an acronym to help you remember how variables are plotted on a graph.

D = dependent variableR = responding variableY = graph information on the Y-axis (vertical, up and down)

M = manipulated variable I  = independent variableX  = graph information on the X-axis (horizontal, side to side)