Catalyst – August (42 + 8), 2010HOMEWORK OUT PLEASE!

An antacid seltzer tablet is dropped into each of two glasses containing equal amounts of water. The temperature of water is 50ºC in Glass 1 and 10ºC in Glass 2. In each glass, bubbles of gas are released as the tablet dissolves. It takes 30 seconds for the tablet to dissolve completely in Glass 1 and 100 seconds for the tablet to dissolve completely in Glass 2.

1. What is the IV? 2. What is the DV?3. What is one CONSTANT?

Today’s Agenda

Catalyst EQ, HW Review, Extra Practice Writing Quality Procedures Plan Procedure for Making Mystery

Goo Exit Question

DON’T FORGET! QUIZ ON THURSDAY!

Today’s Objectives

SWBAT plan a QUALITY step-by-step procedure for making Mystery Goo.

REVIEW OFVARIABLES!

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

Yesterday’s 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?

HOMEWORK QUESTIONS?

Scenario 1

A researcher is studying the effect of sleep on aggression, thinking that less sleep will lead to more aggression. She has some people sleep 6 hours per night, some people sleep 3 hours per night and some people sleep as much as they want. She then monitors aggressive behavior during basketball games among participants. IV? DV? Constants?

Scenario 2

A researcher is curious to find out what effect classical music has on people’s level of relaxation (as measured by heart rate). He suspects that listening to classical music will make people feel more calm and relaxed. He lets one group listen to classical music for one hour. He lets another group sit in a quiet room for one hour (i.e they hear no music). After one hour, he monitors the heart rate of each participant to measure their level of relaxation. IV? DV? Constants?

Scenario 3

A researcher conducts an experiment to assess the effects of alcohol on people's sense of balance. He divides his subjects into three groups: in one group the participants drink one ounce of alcohol, in another they drink two ounces of alcohol and in a third group the participants drink soda. He then watches as each participant tries to walk on a straight line from one corner of the room to the next and notes how many times they stumble outside the line. IV? DV? Constants?

ONTOPROCEDUR

ES!

Importance of a Good ProcedureWe must read and follow directions all the time…

JUST THINK ABOUT DRIVING!JUST THINK ABOUT DRIVING!

Importance of a Good Procedure

Key Point #1: Anyone can understand and duplicate a good procedure.

Understand: The procedure is easy to read and has simple language

Duplicate: The procedure can be repeated

When Things Go Wrong…

When Things Go Wrong…

Key Point #2: You must always have a plan while performing an experiment.

This prevents problems It is important to always read ALL

directions and think before beginning an experiment

ANTICIPATION

Words My definitions Ms. Stroh’s

definitions

Please divide your paperinto three sections.

1. Experiment

2. Materials

3. Procedure

Ms. Stroh’s Definitions

Experiment: a test you do to answer a question and test a hypothesis

Ms. Stroh’s Definitions

Materials: the things you need to perform an experiment (including safety equipment)

Ms. Stroh’s Definitions

Procedure: the instructions you need to follow to to perform an experiment

How to plan a procedure….

Key Point #3: Characteristics of a quality procedure…

1. Materials (including safety equipment)

2. Step-by-step instructions3. Each step is numbered4. Specific and clear

Is this a quality procedure?

Is this a quality procedure?

Materials:

-Beaker -Water

-Tongs -Red dye

-Syringe -Stirrer

Procedure:

Place the beaker on the lab bench. Pour 25 mL of water into the beaker. Add 5 drops of red dye to the water and stir with the stirrer. Heat the beaker up using a hot plate.

Is this a quality procedure?

Materials:-Funnel-Filter Paper-Glass rod-Erlenmeyer flask-Water/sand mixture Procedure:1. Place the filter paper in the funnel.2. Place the funnel in the Erlenmeyer flask.3. Use the glass rod to help pour the water/sand mixture

into the funnel. 4. Collect the filtrate in the Erlenmeyer flask.5. Clean up.

Mystery Goo

Ms. Stroh stayed after school last night and mixed

corn starch and water together. Afterwards, she noticed that the goo had some strange

properties. Sometimes it acted like a liquid, and sometimes it acted like a solid.

She wanted to find out how to make the best goo possible for her students, so she planned an experiment. Then, Mr. Lewis told Ms. Stroh he heard a rumor that you

all wanted to do labs. Mr. Lewis convinced Ms. Stroh to let you do the experiment too!

Mystery Goo

Directions: With your group, select materials and plan the procedure to make…

…a perfect mixture that is 30 mL of water and 1/4 cup of corn starch.

Don’t forget safety equipment!

Safety Equipment

Goggles Apron Gloves Fume hood Fire extinguisher Eye wash Safety shower

Available Materials

Corn starch Water Graduated

cylinder Beaker Bowl or cup

Glass stirring rod

Measuring cup Apron Goggles

Can you think of anything else you might need?

Exit Question

Select the materials and plan the procedure to: (CHOOSE ONE)

make Kool-AidOR

make a sno-ball