# AS Biology Pp.3 (Doupts, Help, Tips ect.)

#### Moi

Assalamu Alaikom
Hey Guys! So i believe biology practical is on tuesday. Figuered we can ask each other for help and tips ect. on this thread. If anyone can sammurize what we need to know/study for paper 3, that would be amazing!

#### Moi

The othr threads are discussing whats coming in the papers and for specific variants...this thread is for general discussion of tips and things we need to know/study for practicals!

#### Moi

can anyone tell me how to do uncertainties in bio with example please?

#### hela

can anyone tell me how to do uncertainties in bio with example please?
For bio when they tell you to calculate the error you should take the smallest scale reading on the apparatus and divide it by two to get the error in the apparatus

Moi

#### Moi

For bio when they tell you to calculate the error you should take the smallest scale reading on the apparatus and divide it by two to get the error in the apparatus
what do you mean by smallest scale reading? example? weirdly..i've never done a question for this before!

#### @yeshaa

How do we do a serial dilution. w12 q31 plz explain???

#### moon

How do we do a serial dilution. w12 q31 plz explain???
take eg 5 cm3 of known concenteration eg 10% of the solution needed to be diluted and add equal volume of distilled water (5cm3) thus you have reduced the concenteration of the solution to half (5%)
if asked to dilute the solution to one-tenth then take eg 1cm3 of 10% solution and add 9 cm3 distilled water hence the formed solution has a concenteration of 1%

#### @yeshaa

take eg 5 cm3 of known concenteration eg 10% of the solution needed to be diluted and add equal volume of distilled water (5cm3) thus you have reduced the concenteration of the solution to half (5%)
if asked to dilute the solution to one-tenth then take eg 1cm3 of 10% solution and add 9 cm3 distilled water hence the formed solution has a concenteration of 1%
can you reply with reference to the question w12 qp 31