Presentation on theme: "Microscale chemistry The international Schools continues to show the UK the way Lead crystals Hydrogen oxygen bang."— Presentation transcript:
Microscale chemistry The international Schools continues to show the UK the way Lead crystals Hydrogen oxygen bang
Reduction of copper(II) oxide with hydrogen
Microscale_Gas_Chemistry.html Microscale gas chemistry website Bruce Mattson, Ph.D., Department of Chemistry Creighton University, Omaha Nebraska, USA Demonstration
Mg (s) +2HCl(aq) → MgCl 2 (aq) + H 2 (g) 60cm mole mole mole 0.06g 2.5 ml of 2MHCl
Present day Standard equipment
First encounter! The reduction of copper oxide with hydrogen This stopped nearly every teacher in the UK carrying out this demonstration
Reduction of iron(III) oxide with hydrogen
The UNESCO- Associated Centre for Microscience Experiments RADMASTE Centre University of the Witwatersrand School of Education 1 st Floor, Marang Block 27 St Andrews Road Parktown, Johannesburg South Africa
The microscale kit on sale in the UK There are many enthusiastic users of this equipment in the UK but there are also a lot of traditionalists who dismiss it without trying it. But many UK teachers are reluctant to test it and look for new applications
My favourite activity using the Comboplate A is an acid solution (3.1 g of boric acid and 2.65 g of citric acid made up to 250 ml of solution): B is an alkaline solution (9.0 g of disodium hydrogen phosphate-12- water and 1 g of sodium hydroxide) (IRRITANT). The pH of the solutions is measured with a calibrated Hanna pH ‘Checker’. 12 Drops of solution of solution A and 8 drops of solution B. 8 Drops of solution of solution A and 12 drops of solution B. 20 drops of A 18 drops of A and 2 drops of B
Colours of indicators in Comboplates
URL_ID=5052&URL_DO=DO_TOPIC&URL_SECT ION=201.html The Global Microscience Project (GPME)
Examples of written materials using this kit
“There was no significant differences in students motivation in their learning “ Professor Norita Mohamed et al, Universiti Sains, Malaysia. Journal of Science and Mathematics in S E Asia, Vol 30, No2, p44 It is reported that from work in Mozambique “Where students have not been exposed to practical work (the microscale approach) does make a positive difference”
Aqueous chemistry of chlorine All done with 2.4 cm 3 of chlorine Open the top of the Petrie dish in a fume cupboard or outside
Micro scale on breakfast television in Kuwait
The RSC initiative of 1999
1.Quantitative work is inaccurate. 2.It’s not what I expect with chemical equipment. 3.It is too small and fiddly. 4.There is no time to practice. 5.The equipment and methods are not in our text books. 6.Exam boards do not specify its use in practical examinations. 7.The equipment is not available cheaply. 8.It is cheap plastic equipment. 9.Pupils will use pipettes and syringes as water pistols! 10.It is not spectacular enough to hold the attention of pupils. Ten objections to microscale are listed below.
Microscale chemistry -but now CLEAPSS is beginning to teach the world Lead crystals Hydrogen oxygen bang
Drop chemistry Original used OHP transparencies but these are no longer easily available in the UK. Polypropylene envelope folders are or you could print in card and laminate them. Instructions are written on the paper.
1.It allows a once dangerous experiment to be carried out more safely 2.It shortens practical time so that lessons are not so rushed. 3.It reduces the cost of equipment and consumable materials. 4.Users report a higher level of concentration amongst pupils and mistakes are quickly rectified. 5.It enables some stunning visible effects when filmed or projected onto a whiteboard. 6.It reduces technician time in disposing and clearing up. 7.It reduces waste, a factor which is becoming more important in the UK. 8.It shows equivalent or better quantitative results (although comparison of techniques is a useful exercise in error analysis). If a microchemical approach satisfies one or more of the following points in a traditional setting, it should be seriously considered.
Making a syringe of hydrogen
The Hofmann voltameter
Micro-electrolysis The electrodes are made of carbon fibre from online kite selling website. 0.2M potassium iodide solution 0.5M potassium bromide solution 0.5M copper(II) chloride solution Moist blue litmus paper
Silver crystals forming during micro electrolysis of 0.01M silver nitrate with paper clip electrodes.
Preparing syringes of toxic gases
Preparing iron(III) chloride
Microtitration You do need a balance to 2 decimal places but Pocket Balances can obtained very cheaply from Amazon for instance.
The CLEAPSS U-Tube channel
Come and try some chemistry, physics and biology procedures at our workshops on Thursday, Friday and Saturday in Lab 166 in the AMS building and/or come and download the PPT and the plus loads more ideas form the lab or the CLEAPSS stand in the marquee Thursday 11 am to 1 pm Thursday 2 pm to 4 pm Friday 11 am to 1 pm Friday 2 pm to 4 pm Saturday 11 pm to 1 pm