Combustion kept simple

When teaching about combustion, we must remember to consider 'complete' and 'incomplete' combustion. During complete combustion, the fuel will produce CO2 and H2O. Incomplete combustion produces CO or C (soot). A neat way of showing this to your class is to just use a bunsen burner. With the air hole closed, explain that the smoky, yellow flame is caused by incomplete combustion - the soot can be collected by placing a cool beaker of water under the flame. Opening the air hole allows complete ...

Conclusion and Evaluation, Aspect 2

  Today we will consider Conclusion and Evaluation (CEv), aspect 2. This aspect deals with the students thoroughly investigating the experimental method. What didn't work well and why? What happened to make the quality of the results not as good as what they should have been? The reasons should relate to the direction of the calculated value with respect to the data book value. For example, if a rate of reaction is less than expected, it would be no good saying that as ...

Conclusion and Evaluation – aspect 1

  The theme for the next couple of days will be Conclusion and Evaluation (CEv). Aspect one is split into three parts and is, in my opinion, the hardest of all of the aspect to achieve a 'c' in. Firstly, the student needs to write a good IB level conclusion - what do the results actually mean. There is no longer a 'hypothesis' to write, so this is the part of IA that is really testing an understanding of chemical knowledge. Secondly, the student ...

Data Collection and Processing, Aspect 3

By Thursday, November 4, 2010 , , , , 0

DCP, aspect 3: Students seem to find this difficult to achieve a 'c'. The aspect is looking for students to correctly present their final answer (to the correct number of significant figures) and to display an uncertainty / error value (to the correct number of significant figures). We will consider each part separately: Firstly, the correct number of significant figures. The student should look back through all the data used in DCP aspect 1. The final answer should have the same number of ...

Data Collection and Presentation, Aspect 2

By Wednesday, November 3, 2010 , , , , 0

Today we will consider DCP, aspect 2. This aspect deals with the processing of the raw data collected in aspect 1. It should involve an 'IB CHEMISTRY type' calculation - it should not be simply calculating averages or calculating 1 / t (for a rate).  The calculation should be demanding enough that an IB Chemist should be able to carry it out (but not another student following another IB subject). If the students carries out the processing of the data correctly, award ...

Data Collection and Processing, aspect 1

By Tuesday, November 2, 2010 , , , , 0

Today, we will move away from Design and consider 'Data Processing and Presentation' (DCP) aspect 1. DCP is all about collecting raw data, displaying it and processing it. DCP aspect 1 deals with correctly and accurately presenting raw data. Data should be put into a table with a title. Any raw data collected can be split into qualitative (an observation - eg, I saw some bubbles) and quantitative (eg, 30.5 oC). Tables of data should contain both quantitative and qualitative observations to achieve a ...

Design, aspect 3

By Monday, November 1, 2010 , , , , 0

Today we will focus on Design, Aspect 3. In order to achieve a 'c in this aspect, the student must write a detailed method. The emphasis is on the word detailed. The student should essentially be able to give another IB Chemist the method and they would be able to carry it out. Often, methods are not detailed enough. For example, in a cell reaction lab the student writes 'connect the voltmeter and record the voltage' - there is not enough detail ...

Design Aspect 2

By Sunday, October 31, 2010 , , , , 0

  Sorry for the delay - I have been on my half term holiday :lol: So, my last posting covered Design, Aspect 1 - today, it is onto Design, Aspect 2. This criteria is all about controlling the variables listed in Design, Aspect 1 in the Method. Your students should cross reference their listed variables in Design, Aspect 1 and write how they will realistically control them. The most common mistake is writing something obscure in Design, Aspect 1 (for example, controlling the room ...

Design Aspect 1

  Today we will look at Design aspect 1. This criteria is really split into two parts - the research question and the variables. To obtain a 'c', the student needs to produce a focused research question. A research question along the lines of 'How does  concentration effect cell voltage?' would not be considered focused enough - this would be awarded a 'p'. A more focused question would talk about 'How do concentrations of 0.1, 0.2, .0.3, 0.4 and 0.5 mol dm-3 copper sulfate ...