Results are out! Find what you need...fast. Get quick advice or join the chat
Hey! Sign in to get help with your study questionsNew here? Join for free to post

Anomalous results?

Announcements Posted on
Fancy winning £500? Join the Summer Bucket List Challenge and beat the holiday boredom! 06-07-2015
Waiting on IB results? Our IB results hub explains everything you need to know 01-06-2015
  1. Offline

    ReputationRep:
    I always lose marks in homeworks for the reasoning the anomalous results. It's normally the only section I lose marks in, evaluation, and it's getting a bit annoying.

    Let's this we're measuring temperature changing after a reaction is underway. Why might one get an anomalous result? Perhaps misreading the thermometer, or the stopwatch?

    It seems to me if it was adding too much/little of a reactant would cause all results to be wrong..?
  2. Offline

    ReputationRep:
    Yeah work on things like the human error you've mentioned

    also if your measuring temperature changes think about stuff like if you're losing heat to the environment or whether your starting point was ACTUALLY the starting temperature


    hope that helps....
  3. Offline

    ReputationRep:
    - Stopwatch: Human error will be the most significant; your reaction time from when you first see whatever you're looking for to when you hit that button. That will also vary every time you do it. Minor to that is the instrumental error.
    - Thermometer: ±0.5 if you're measuring in 1ºC intervals
    - Mixing: Sometimes you have to mix the reactants...
    (etc)

    Then you need to say how you can reduce your errors. Well instrumental aren't really that significant, you could measure to a higher degree of accuracy but that will only make a difference if your measurements are quite small, e.g. if you’re measuring temperature at 1 ºC intervals from 0-5 ºC, the error will be much more significant than the temperature from 400-405 ºC.

    Human is difficult to overcome as well – if you’re working as a pair just make sure the same person is using the stopwatch every time. And for the end point – well if you’re looking for a colour change you could use a colorimeter or something, which would be more accurate in judging your end point. Or you could quench the reaction at different points and carry out a titration.

    Method error – depends on your experiment really. Make sure that if you stir solution A 5 times, you stir solution B 5 times too :tongue:. You might be able to think up a better way of conducting the experiment.

    General - comment on number of repeats, exclude anomalous data if you have other sets of data that are better, take averages, compare to literature values, etc.

Reply

Submit reply

Register

Thanks for posting! You just need to create an account in order to submit the post
  1. this can't be left blank
    that username has been taken, please choose another Forgotten your password?
  2. this can't be left blank
    this email is already registered. Forgotten your password?
  3. this can't be left blank

    6 characters or longer with both numbers and letters is safer

  4. this can't be left empty
    your full birthday is required
  1. By joining you agree to our Ts and Cs, privacy policy and site rules

  2. Slide to join now Processing…

Updated: March 3, 2009
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

New on TSR

IB results chat

Good luck everyone - loads of support here

Study resources
x

Think you'll be in clearing or adjustment?

Hear direct from unis that want to talk to you

Get email alerts for university course places that match your subjects and grades. Just let us know what you're studying.

Quick reply
Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.