IB Internal Assessment (Lab) Scoring

DESIGN

DESIGN- Aspect 1Defining the problem and selecting variables

Complete/2 Formulates a focused problem/research question and identifies the relevant variables.

Partial/1 Formulates a problem/research question that is incomplete OR identifies only some relevant variables.

Not at all/0 Does not identify a problem/research question AND does not identify any relevant variables

Examples of scoring: Formulates a focused problem/research question and identifies the relevant variables.

• Background Info: Catalase is an enzyme found in nearly all organisms exposed to oxygen. In our cells it is located in peroxisomes & converts harmful hydrogen peroxide into water & oxygen. 1

QUESTION: What is the effect of altering the pH on the function of catalase?– Is this question focused? (Do you know exactly what the

experimenter wants to find out?)• Do you know what levels of pH are going to be tested?• Do you know how the “function” of the enzyme will be

determined? SCORE: 11 http://en.wikipedia.org/wiki/Catalase IMPORTANT!

Examples of scoring: Formulates a focused problem/research question and identifies the relevant variables.

• Background Info: same as previous slide

• QUESTION 2: What is the effect on the rate of oxygen production when hydrogen peroxide and catalase are in a pH environment of 3, 4, 5, 6, 7, and 8?– Is this question focused? (Do you know exactly what

the experimenter wants to find out?)• Do you know what levels of pH are going to be tested?• Do you know how the “function” of the enzyme will be

determined? SCORE: 2

Examples of scoring: Formulates a focused problem/research question and identifies the relevant variables.

• Background Info: The movement of water from areas of high water availability to areas of lower water availability is an important process in all living things. 1 Without it, water would not enter roots cells from the soil nor would water be able to enter the cells of out body. 2

• QUESTION: How do different concentrations affect osmosis?– Is this question focused? (Do you know exactly what the

experimenter wants to find out?)• Do you know what is going to be tested?• Do you know how the movement of water will be determined?SCORE: 0

1 http://arbl.cvmbs.colostate.edu/hbooks/cmb/cells/pmemb/osmosis.html

2 -jdldjodgopdgdopd

IMPORTANT!

Examples of scoring: Formulates a focused problem/research question and identifies the relevant variables.

• Background Info: The movement of water from areas of high water availability to areas of lower water availability is an important process in all living things. 1 Without it, water would not enter roots cells from the soil nor would water be able to enter the cells of out body. 2

• What would you need to know in order to write a focused research question?

• Your turn! Use this info. to write one.1 http://arbl.cvmbs.colostate.edu/hbooks/cmb/cells/pmemb/osmosis.html

2 -jdldjodgopdgdopd

What are variables?

• any factor, trait, or condition that can exist in differing amounts or types

• An experiment has three kinds of variables:– Independent (IDV) what is different in order to

test the hypothesis/answer the question– Dependent (DV) the data that is collected

• What data are you collecting as you stand at the lab bench?

– Controlled these are all the other things that could be different but you want to keep constant • This ensures that the data you collect allows you to

answer the question with confidence

Aspect 1 variables: IDV & DV• QUESTION 2: What is the effect on the rate of

oxygen production when hydrogen peroxide and catalase are in a pH environment of 3, 4, 5, 6, 7, and 8?– Independent (IDV):• Levels of pH (3, 4, 5, 6, 7, 8)

– Dependent (DV):• Correct DV example: oxygen levels

– at time 0 sec, 30 sec, 60 sec, 90 sec, etc. (this is 4 pieces of data)

• Incorrect DV example: rate of oxygen production – (you had to do math to get this #)

DESIGN- Aspect 2Controlling the Variables

Complete/2 Designs a method for the effective control of the variables.

Partial/1 Designs a method that makes some attempt to control the variables.

Not at all/0 Designs a method that does not control the variables.

Controlled variables: Aspect 2• QUESTION 2: What is the effect on the rate of oxygen

production when hydrogen peroxide and catalase are in a pH environment of 3, 4, 5, 6, 7, and 8?– Controlled variables: What things can you think of that must

be kept constant? Brainstorm with a partner!• Temperature of H2O2 & catalase

• Volume/amount of H2O2 & catalase

• Source of H2O2 & catalase• Time intervals oxygen readings are taken• Equipment taking the reading

– What are things that are not really important to list here?• All IDV levels tested in the same room• Same level of humidity outside• Same amount of light • Same person pouring H2O2 & catalase together

Controlled variables are displayed in a chart & they are included in the procedure.

Controlled Variables(state the variable; no

magic #; list what is needed

How Method Allows for the Control of these Variables

(explain how not “why”)Temperature of enzyme &

substrateBoth the hydrogen peroxide & catalase were

kept at room temperature (23ºC)Y Z

Controlled Variables Chart:

Note the use of the metric system!

Practice scoring: IB Sample #2*Before we look at the controls, let’s score Asp1 while we read.

QUESTION (this person embedded their question information in a hypothesis)

SCORE: 0DESIGN ASP1 SCORE: ?

Aspect 2: Controlling the variables

• What controls do you see in this procedure?• Same person tasting leaf• Same scale used to rate the leaf bitterness• Mouth cleansing procedure for after eating a leaf (crack & water)

• What else could/should have been controlled?• Amount of leaf material tasted/tested• Part of the leaf tasted/tested

SCORE: 1

Practice scoring: IB Sample #3(Asp 1 first, then Asp 2)

QUESTION (this person embedded their question information in a hypothesis)

DESIGN ASP1 SCORE: ? SCORE: 2

Aspect 2: Controlling the variables Example #3 (pass out procedure handout)

• What controls do you see in this procedure?• Test tubes left in water bath for 30 minutes• All apple cube sizes are 1cm3

• Same pH• Same amount of substrate (2 cubes of apple)• Volume of enzyme (pectinase) in each tube

• What else is controlled but isn’t listed in the chart?• Total volume in each test tube• Same type of apple• Method of crushing the apple to extract juice

SCORE: 2

DESIGN- Aspect 3Developing a method for collection of data

Complete/2 Develops a method that allows for the collection of sufficient relevant data.

Partial/1 Develops a method that allows for the collection of insufficient relevant data.

Not at all/0 Develops a method that does not allow for any relevant data to be collected.

“Method,” “Sufficient,” “Relevant”:• Develops a Method: Procedure is complete & explains all

necessary steps

• Sufficient: – at least 5 different levels of IDV– at least 3 trials at each level of IDV (5 is better)

• Relevant: – data collected will actually allow you to answer the question

• Ex: If you are trying to measure the amount of bacteria that is on your desk as the day progresses & it is used, you must sanitize the desk before you begin the experiment.

Aspect 3: Develops a method… tannin in leaves experiment (Ex #2)

• All steps included that allow another person to complete the experiment?• No; How were the leaves chosen?

• Sufficient Data?• No; only 3 levels of IDV• Not really quantitative; more qualitative (better if he quantified the amount of light)

• Relevant Data• Yes; Student is equating bitter tannin taste to level of light & he is tasting for

bitterness.

SCORE: 1

Aspect 3: Develops a method… pectinase & pectin (Ex #3)

• All steps included that allow another person to complete the experiment?• No; Students Introduction mentioned a rate of reaction for pectinase

& the experiment didn’t discuss how to measure the rate of the reaction.

• Sufficient Data?• No; only 1 trial completed for each level of IDV (need at least 3; 5 is

better)• Reality of how much juice 2 small apple cubes will yield small;

apparatus says to use 25mL beaker & this would be too big

• Relevant Data• Yes SCORE: 1