Catalyst – January (42 + 3), 2009

1. What question is this data table answering?

2. What is one conclusion we can make from looking at this data table?

3. Write a hypothesis to answer this question: Why is hydro (water) power used so greatly?

Write in complete

sentences!

Don’t talk during

the Catalyst!

Today’s Agenda

Catalyst Variables Notes and Practice Time

I-N-D-E-P-E-N-D-E-N-T! DEPENDENT CONSTANTS

Exit QuestionHOMEWORK TONIGHT!QUIZ ON THURSDAY!

GUEST SPEAKER ON FRIDAY!

Today’s Objectives

SWBAT identify independent, dependent, and constant variables in a scientific experiment.

Experimentation

Key Point #1: A proper experiment always has an independent variable and dependent variable. The purpose of an experiment is to test how changing ONE THING affects something else.

Variables

Independent Variable: what causes the change we are measuring (acts independently)

Dependent variable: what gets changed (depends on other things)

Remember Variables are always CATEGORIES of

things: time, amount, frequency, size, type Variables are NEVER specific things!!!

Demo

http://www.unitedstreaming.com/videos/dsc/externalApplications/virtual_labs-es/Plants/index.html

Teacher Models

Scientists have discovered something shocking: if you eat a lot of candy, then you will gain fat. What is the independent variable?A. Eat a lot of candyB. Type of candy you eatC. Amount of candy you eatD. How much weight you gain

Teacher Models

Happy students learn more in school. So, Ms. Stroh believes that starting school later would increase test scores. What is the dependent variable?A. Starting school laterB. Happy studentsC. Time that school startsD. Test scores

NEW PROCEDURE!

WHITEBOARDS!

Whiteboard Practice

When Ms. Stroh says “GO!” Send one member of your group to

get whiteboards and markers for everyone (back lab bench)

Send up another member of your group to get napkins for everyone (green bin)

Hurry! Remember, we want to stay under 3 minutes of transition time!

Whiteboards 1

Ms. Stroh believes that the more you study, the better grades you’ll earn. What is the independent variable?A. Studying moreB. Amount of time you studyC. Grade earnedD. Type of test

Whiteboards 2

Shanel is always cold in class. She hypothesizes that if she wears many layers of clothing to school, then she will be warmer. What is the dependent variable?A. Number of layers Shanel wearsB. How cold Shanel isC. Temperature of the roomD. Shanel will be warmer

Whiteboards 3

Ms. Stroh’s students want to test how easily bought off he is. Students who give him an apple get a “C.” Students who give him candy get an “A.” What is the independent variable?A. Type of foodB. Apples and candyC. “A” on the report cardD. Report card

Whiteboards 4

Jenika hates running, but loves listening to music. She believes that if she listens to music while running, then she will run more often. What is the dependent variable?A. She will run more oftenB. Listens to music while runningC. Frequency that Jenika runsD. What Jenika listens to

If you’re having trouble…

4 minutes 26 mg of baking

soda Lifting weights

every day Medium t-shirts Bullfrog 16 candles Never gets sick

Time to get dressed Amount of baking

soda Frequency of lifting

weights Size of t-shirts Type of frog Number of candles Degree of health

WRONG RIGHT

Review

Ms. Stroh believes that the more you study, the better grades you’ll earn. What is the independent variable?A. Studying moreB. Amount of time you studyC. Grade earnedD. Type of test

Review

Shanel is always cold in class. She hypothesizes that if she wears many layers of clothing to school, then she will be warmer. What is the dependent variable?A. Number of layers Shanel wearsB. How cold Shanel isC. Temperature of the roomD. Shanel will be warmer

Review

Ms. Stroh’s students want to test how easily bought off he is. Students who give him an apple get a “C.” Students who give him candy get an “A.” What is the independent variable?A. Type of foodB. Apples and candyC. “A” on the report cardD. Report card

Review

Jenika hates running, but loves listening to music. She believes that if she listens to music while running, then she will run more often. What is the dependent variable?A. She will run more oftenB. Listens to music while runningC. Frequency that Jenika runsD. What Jenika listens to

Guided Practice Worksheet

8 minutes to complete3 minutes to compare answers

KEEP THIS to help you with homework tonight

Constants

Key Point #2: Everything but the independent and dependent variable must be kept constant. Constant: variable we keep the same

If many different things change at once, we don’t know what causes the change!

Example

Let’s say we want to design an experiment to determine what causes GSP to win fights.

Number of fights that GSP wins

Answer in notes

Jay-Z hypothesizes that if he stops cussing, then he will sell fewer CDs because students like cussing. What is the IV? What is the DV? What are the constants?

Remember, variables are CATEGORIES.

If [Jay-Z] stops cussing, then he will sell fewer CDs because students like cussing. IV

Frequency that Jay-Z cusses How often Jay-Z cusses Amount of curse words in Jay-Z songs

DV Number of CDs Jay-Z sells How many CDs Jay-Z sells

Constant Amount of money CDs cost Number of tracks on each CD How good each CD is

Practice

You want to know when in the year there are the most love bugs. Every night, you record how many love bugs you find outside.

IV =

DV =

Constant =

Time of year (season/month)

Amount of love bugs

Practice

Jenika needs to run a 6 minute mile to pass PE. She believes that if she runs every day, then she will be able to run faster.

IV =

DV =

Constant =

Frequency that Jenika runs

Mile time

Practice

Students of different genders were given the same puzzle to assemble. The puzzle assembly time was measured.

IV =

DV =

Constant =

Type of gender

Time to assemble puzzle

If there are more students, then there will be more school

buses.

IV =

DV =

Constant =

Amount of students

Number of school buses

If the cost of beignets increases, then fewer will be sold.

What depends on what?

IV =

DV =

Constant =

Amount each beignet costsNumber of beignets sold

IV = Number of free agents

DV = Number of games won

Constant =

If the Saints sign more free agents, then they will win more games.

Conclusion

A proper experiment always has an independent variable and dependent variable. Everything but the independent and dependent variable must be kept constant. Independent Variable: what causes the

change we are measuring Dependent variable: what gets changed Constant: variable we keep the same

Exit Question

Let’s say you want to figure out if drinking milk actually makes you taller. So you drink a glass of milk every day, and record your height every day.

1. What is the independent variable?2. What is the dependent variable?3. What are at least two constants?

Write in complete sentences!

Don’t talk during the Exit Question!