Catalyst – August ( ), 2010 HOMEWORK 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 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 OF VARIABLES!

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?

ONTO PROCEDURES!

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

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 paper into three sections. 1. Experiment 2. Materials 3. Procedure

Ms. Stroh’s Definitions EExperiment: a test you do to answer a question and test a hypothesis

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

P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 instructions 3. Each step is numbered 4. Specific and clear

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-Aid OR make a sno-ball