Measuring small volumes June 2013 Paul Beaumont

[Evaluating experimental procedures p. 50] Learners should be able to…: … identify sources of error in measurements and observations identify and comment on the reliability of results ...

Skills of scientific experimentation, investigation and enquiry Evaluating (p 8) Learners should be able to…: … identify sources of error in measurements and observations identify and comment on the reliability of results ...

Syringes / pipettes Variable volume 0 - 20 μL, 0 - 200 μL, 0 - 1000 μL ~ £200 per syringe

Syringes / pipettes Single volume 5 μL, 10 μL, 20 μL, 25 μL, 50 μL and 100 μL £16 per syringe

Making your own microsyringe Accuracy? Precision? Cost?

Equipment

Equipment 10 mL 20 mL 50 mL 100 mL 200 mL

Operation / activity Draw up some air - ~ 100 mL No more than 200 mL! Measure mass of empty weighing boat Take ca. 150 mL - expel excess until 100 mL left Repeat 9 times - measure mass Record mass on board Repeat using 50 mL increments