“IN A LITTLE YOU CAN SEE A LOT”:

The impact of practical microscale chemistry

on chemical education

CLEAPSS www.cleapss.org.uk

CLEAPSS provides

• health and safety including model risk assessments,

• chemicals, living organisms, equipment,

• sources of resources,

• laboratory design, facilities and fittings,

• technicians and their jobs,

• D&T facilities and fittings.

It has around 2000 associate members, ie:

Local government schools

Independent state and fee paying schools

Colleges of Further Education

Overseas institutions,

Teacher-training establishments and learned bodies such as the Royal Society for Chemistry, Science learning centres, Field centres, museums, etc,

Examination centres and Curriculum developers.

CLEAPSS provides Termly newsletters for primary and secondary schools,

a wide range of free publications,

model and special risk assessments,

low-cost training courses for technicians, teachers and local authority officers,

a telephone Helpline which takes almost 7000 calls per year a monitoring service, eg, for mercury spills,

evaluations of equipment and advice on repairs,

Assistance to Government and Quasi-government institutions (eg Health & safety Executive)

a H&S / Review service for publishers, exam boards and other organisations producing teaching resources.

Microscale chemistry approach • Allowing the teaching of chemistry in

developing countries

• Instigating green & environmental issues

Perspex

Iron/sulfur reaction

Cracking

Reduction of metal oxides with hydrogen

Improves safety

Crucible replacement

Hofmann Voltameter Colorimeter

Less expensive equipment

Balances

Microelectrolysis

Drop Chemistry

Working with toxic gases, no fume cupboard/hood required.

And uses smaller volumes of chemicals

Disposal not such a great issue

•Improves classroom management

But let’s look at issues which are less obvious at first but may be more important

Seated students

Improves classroom management

Balances

Dropping bottles

Students work more efficiently allowing the teacher more time to teach

• Improves classroom management

•Aids improved understanding of difficult chemical concepts leading to visualization of models

But let’s look at isssues which are less obvious at first but may be more important

The Johnstone triangle of the facets of chemical knowledge: students must learn in three different representations at once, and how to inter-relate each new concept or fact in all three domains. Here I have expanded the triangle into a rectangles by adding RELEVANCE

Aids improved understanding of difficult chemical concepts leading to visualization of models

Diffusion of gases and particulate theory of matter

Ammonia gas diffuses from the central

container to react with metal ions

Microelectrolysis of CuCl2 (aq) produces chlorine which reacts with KI(aq), KBr(aq) and moist blue litmus

Conductivity

Movement of ions

Evidence for the existence of ions

One grain of salt dissolved in the puddle can cause the solution to conduct indicated by the LED

Electrolysis of a molten salt

Diffusing precipitates

Solubility and precipitation

Chemistry is a battle of electrostatic attraction between particles carrying electrostatic charges • Ionic bonds • Covalent bonds • Intermolecular attraction • Solvent ion attraction

Interpretation using models

Electrostatically charged rod deflects water

0 0.2 0.4 0.6 0.8 1 1.2

2

2.5

3

3.5

4

4.5

volume of acid

Cu

rre

nt

0.1M H2SO4 against 1 ml of 0.1M NaOH

Stoichiometry (work in process)

To 9v battery and multimeter

Microtitration technique

• Improves classroom management

• Helps students develop improved understanding of difficult chemical concepts

•Students work more efficiently allowing the teacher more time to teach. (Is this because there is a lower cognitive overload?)

But let’s look at isssues which are less obvious at first but may be more important

Perception filter where the senses operate to provide information

Short term working memory which can

hold a limited number of independent items. 7 items plus or minus 2

I can get information from my long-term memory to provide an

explanation.

Long term memory which is not large in students and teachers are trying to make it larger. This will hold both correct and incorrect interpretations of events.

Many different events will be-connected with each other, either correctly or incorrectly.

It also holds memories of common sense explanations but common sense may not always be correct.

As short term memory events are inserted from the working memory they may reinforce or contradict memories here.

Conflicts here can make me terribly confused!

Response back to teacher

Event happens

Cognitive load

Titration

Turn a clamp or a Hoffman clip to of drops of solution

• Use the microscale titration method to introduce the subject. Gradually move to the standard equipment.

• Acid base yes, but can also do redox, complexometric and precipitation

Complexometric titration of hard water

Measurements are made by weighing and assume all solutions have te same density

Voltaic cells lead to the activity series Compare the voltages wrt Magnesium, not copper

• Improves classroom management

• Helps students develop improved understanding of difficult chemical concepts

• Students work more efficiently allowing the teacher more time to teach. (Is this because there is a lower cognitive overload?)

•New and original experiments

But let’s look at isssues which are less obvious at first but may be more important

PARAMAGNETISM

Demonstration of paramagnetism in transition compounds with powerful neodymium magnets

PARAMAGNETISM IN COMPLEXES

MORE ALKENES Dehydration of propan-2-ol to make propene

Propene preparation.mp4

EXOTIC CATALYSIS Hydrogenation of an alkene

C3H6 + H2 →C3H8

Haber reaction Environmental chemistry

Acid rain

Ozone ozone.wmv

• Improves classroom management

• Helps students develop improved understanding of difficult chemical concepts

• Students work more efficiently allowing the teacher more time to teach. (Is this because there is a lower cognitive overload?)

• New and original experiments

•Brings to life important techniques

But let’s look at issues which are less obvious at first but may be more important

QUICK TESTING OF ALCOHOLS This is 1.4M

acid

Quick Thin Layer Chromatography (6 min in 90s)

Quick Thin Layer Chromatography of Chlorophylls

And look what happens in

UV light

Quick Thin Layer Chromatography of Black Biro Inks

Gases in a Petrie dish

Colorimeter Gases in Syringes

Comboplate

Microtitration

Chemistry in a sealed Pasteur pipette

Chemistry on plastic sheet, Bottle-top, Crucibles and Microelectrolysis

Hoffman Voltameter, microelectroylsis

Spirit burner Conductivity tester

Bicycle spoke deflagrating spoon

Thank you to the world of microchemists

Portable organic chemistry set

Thanks •To Professor Supawan Tantayanon and her team

•To

•To CLEAPSS & Director Steve Jones

•Dr Kay Stephenson (ideas, improvement)

•Mary Owen, Jane Major and Emma Warwick (The CLEAPSS Technicians)

Copper crystals formed during electrolysis

Microscale chemistry: “in a

little, you can see a lot”

And it is all rather beautiful!