7 ideas for scaffolding learning
1. Using different methods to achieve the same outcome
One of the topics I find that students need a lot of scaffolding for is writing ionic formulae. It is one of the first really abstract topics that students come across and they struggle to link their bottom-up practice with top-down understanding. In order to help students make sense of ionic formulae I teach them three different methods for determining the formula in the same lesson and then allow students to choose their preferred method to complete their plenary task. The three methods are as follows:
Using ion cards where the size of the card is proportional to the charge and the cations are pink and anions green. The students need to determine the correct formula by matching up the correct ion cards in a ratio which ensure there is the same area of pink as green.
Using the criss-cross method in which students swap the moduli of the charges on the ions and cancel down to determine the ratio of the ions.
By drawing out the atoms and showing the transfer of electrons from the metal to the non-metal atom and ensuring that all electrons are accounted for (I also have giant bibs and tennis balls for a human-sized demonstration of this).
Using the three methods all together reinforces the concept of balancing charge in different ways. This is known to improve bottom-up learning: practice of the same task is far more effective when done in different ways or in different situations. Furthermore, sometimes when students struggle with the first method, it starts to click during the second, and when they look back at the first method they can understand why this also worked. This builds student understanding and top-down learning of the concept.
2. Using thinking maps to structure students' ideas
I recently took the National STEM Centre's online course on Differentiating for Learning and was reminded about the power of the tools known as thinking maps in teaching Chemistry. I had gone through a phase of using them all the time in my NQT year and had since slipped into only using them then they were already on high quality resources. However, a lot of the resources I made during that phase are still in regular use, so maybe there is something in the use of Thinking Maps which makes the resources more useful...
The topic I use thinking maps for the most is Structure and Bonding. In particular the Double Bubble Map is useful for students to compare the features of different types of bonding, e.g. ionic and metallic structures. The Multi-Flow map is invaluable as a way of encouraging students to link their explanations, from the particle level to the properties of the structure. These Multi-Flow maps can be developed into fairly complex structures, like the one below, in which students fill in the gaps to build up their understanding.
However, students can also build their own Flow Maps using a similar example which scaffolds their learning. In the example below, students use a flow map which explains why lithium has a higher melting point than sodium to create a Flow Map explaining the relative melting points of magnesium and calcium. Once students have filled this in they can then attempt to answer the question in prose in order to further develop their learning.
What these thinking maps are doing is allowing students to pit their learning into a big-picture context which helps with the neural process of chunking. When combined with practice, and active learning of the information, this ensures that the learning can be accessed efficiently by the brain in different situations.
3. Using writing frames
Writing frames can be useful, even in science lessons where we rarely get students to complete any extended writing. Firstly, although students are not required to complete particularly long-answer questions on submit written coursework at IGCSE, we would be remiss as teachers if we did not on occasion expect students to carry out some research and present their ideas, as this is a key skill in science at a higher level.
I have generally carried out these sorts of tasks with Key Stage 3 students as a way of encouraging them to think more deeply about the quality of their research before they present the final item. For example, in one such task students were asked to write a letter suggesting who was the discoverer of oxygen to the Royal Society so that a prize for discovering new elements could be named after him (no women appear to be in contention for this great honour!). In class I showed students some extracts from Jim Al-Khalili's Chemistry: A Volatile History. Then for homework the students used the websites I had provided them with to complete a writing frame and help them to structure their ideas. The writing frame included a box for factual information, their opinion, evidence to support their ideas and arguments against their ideas which they needed to respond to. I then provided formative feedback on these before students wrote the letter for homework the following week. The quality of work that all students produced for this one hour (total) task was exceptional. Furthermore, the success of students in the task was in no way related to whether or not they had chosen Priestley or Lavoisier (or anyone else for that matter). It was the quality of their arguments and their use of evidence which was supported and subsequently developed by the task.
4. Using 'stepping stone' activities to move from understanding of one idea to a related concept
This is one of my favourite ways to scaffold learning in a practical context. It involves starting with a concept that students already know and understand, for example a practical method, and changing the circumstances one piece at a time for students to derive a different practical method for a related situation.
A good example of this is making soluble salts via the titration method. Firstly I give the students a simple challenge to discuss in groups for 3 minutes:
I also have the apparatus out on the front bench. Once each group has determined a method I ask for feedback from the groups and act out their method using my apparatus. Once they have given me the best possible method (usually by the groups giving each other feedback) I change the apparatus...
In order for students to derive the titration method, they do not strictly need to go through the version with a balance, but I find it helps students to consolidate and build on their ways of perfecting the method from the first stepping stone. Students only get 1 minute for this stage. In the next stage I remove the balance and replace it with a burette, and the following stage the beaker and Pasteur pipette are replaced with a conical flask and a glass pipette. Students are generally able to give me a detailed explanation of how they would complete this practical through this stepping stone approach.
In the next part of the lesson, students complete a titration in pairs (having been given a few pointers). Finally, I set their homework which links them back to the task of making sodium chloride using a titration and their prior learning about how to collect a soluble salt from a solution.
5. Using Venn diagrams to organise students' thoughts
Similarly to the use of thinking maps above, using Venn diagrams helps students to link their understanding of different topics together and assist in top-down chunking of their learning.
A simple idea for usine a Venn diagram in Chemistry is to sort salts into 'soluble' and 'insoluble', recognising that partially soluble salts would be placed in the intersection. If students are given a table showing solubility organised by ions, this activity of re-sorting of the compounds by solubility is a very useful way of structuring the active learning process for recall of the solubility rules.
One of the best examples I have seen for Venn diagrams in Chemistry is the RSC Gifted and Talented exercise in which students work in groups to correct a Venn diagram which is incorrect (pictured below).
This process of students evaluating a way of organising elements, mixtures and compounds is an extremely powerful way to improve their big-picture understanding of the concepts they are learning.
6. Using sequences to approach longer answer questions at A-level
Students having set approaches to answering certain types of questions is a useful way of scaffolding their learning until they no longer need that support. Once students have fully grasped the learning they can, if they choose to, answer the question freely without missing out any of the key criteria required by the examiner.
I use this strategy when teaching students about ionisation energies at A-level. If a question asks students to compare the ionisation energies of any two atoms I tell them that they must refer to the following three points in their answer:
the distance of the electron from the nucleus
the nuclear charge
I call it the DNS approach. for each factor they need to state whether or not it has changed and how it will effect the ionisation energy. Their answer must then finish with a statement about the overall change in ionisation energy.
When teaching NMR I utilise this strategy again. For every peak in the NMR, students must refer to the following:
the integration trace
the spin-spin splitting
the chemical shift
In that order. They then put together pieces of the molecule by analysing each peak, and only worry about putting the whole molecule together at the end. This means that even if they get the wrong answer they will get most of the marks and gives all students the confidence that they can do well in the question.
7. Taking away teacher support with for subsequent examples
This is probably the most common form of scaffolding taking place in science classrooms across the country. But it is effective and it gives the students the toolkit they need to get on with embedding the learning independently through practice.
The example I am going to give is actually from a very recent lesson in which the students' confidence skyrocketed through the use of this strategy.
Earlier in the lesson the students and I had worked out the mechanism for electrophilic aromatic substitution on the board using a generic electrophile, E+. The students had then drawn the mechanism on their mini-whiteboards using other electrophiles which were from the examples used at A-level. Once the students were confident using this mechanism, we worked through the whole mechanism for the bromination of benzene on the board together, including the production of the bromonium ion and the regeneration of the catalyst at the end. The second mechanism we looked at was Friedel-Crafts alkylation and the students and I worked through the generation of the carbocation together, and they wrote the mechanism into their notes. They then deduced the rest of the mechanism on their mini-whiteboards which I checked before the wrote it into their notes. Finally the students worked out all of the steps for Friedel-Crafts acylation on their mini0whiteboards on their own which I checked before the added this into their notes.
What was so successful about this method of teaching electrophilic aromatic substitution was that all of the students, regardless of their prior attainment (or confidence in drawing mechanisms), were able to build up the mechanism for acylation using the scaffolding that I had put in place. And that support so that everyone reaches the highest levels is what scaffolding is all about!