Paper 6

What is an INDEPENDENT variable

• The variable that is changed by the investigator

• The variable that is measured

• the variable that should be kept constant so as not to affect the result of the dependent variable

What is a DEPENDENT variable

• The variable that is changed by the investigator

• The variable that is measured

• the variable that should be kept constant so as not to affect the result of the dependent variable

What is a CONTROL variable

• The variable that is changed by the investigator

• The variable that is measured

• the variable that should be kept constant so as not to affect the result of the dependent variable

How can you make an experiment more RELIABLE

• Do it 3 times and then take an average

• exclude anomalies from the data

• Use the same type of sample

• Use appropriate apparatus

How can you make an experiment more VALID

• Do it 3 times and then take an average

• Use the same volume of solution

• Use the same type of sample

• Use appropriate apparatus

How can you make an experiment more ACCURATE

• Do it 3 times and then take an average

• Use the same volume of solution

• Use the same type of sample

• Use appropriate apparatus

How many decimal places should you answer with?

• 1 decimal place even if the rest of the table is with whole numbers

• A whole number even if the rest of the table is to 1 decimal place

• If the rest of the table is to 1 decimal place then you should answer with 1 decimal place even if your answer is a whole number

• If the rest of the table is whole numbers then you should answer with 1 decimal place even if your answer is a whole number

What is the test for STARCH?

• Add a few drops of iodine and gently shake - it should turn from brown/orange to blue/black

• Add 2cm3 of Benedicts and boil. It should turn from blue to green to yellow to orange to red

• Add a few drops of biuret reagent and shake gently. It should turn from blue to purple

• Add 2cm3 of ethanol and shake gently. Then add an equal volume of distilled water. It should turn a milky-white colour

What is the test for REDUCING SUGARS?

• Add a few drops of iodine and gently shake - it should turn from brown/orange to blue/black

• Add 2cm3 of Benedicts and boil. It should turn from blue to green to yellow to orange to red

• Add a few drops of biuret reagent and shake gently. It should turn from blue to purple

• Add 2cm3 of ethanol and shake gently. Then add an equal volume of distilled water. It should turn a milky-white colour

What is the test for FATS/LIPIDS?

• Add a few drops of iodine and gently shake - it should turn from brown/orange to blue/black

• Add 2cm3 of Benedicts and boil. It should turn from blue to green to yellow to orange to red

• Add a few drops of biuret reagent and shake gently. It should turn from blue to purple

• Add 2cm3 of ethanol and shake gently. Then add an equal volume of distilled water. It should turn a milky-white colour