Decarbonation of Soda Water

My Year 12 Chemistry class were working on this *exciting* prac this afternoon, as part of developing their understanding of the equilibrium that occurs in the dissolution of carbon dioxide in water.

In the past, I have done this experiment as you might expect – take a small can of soft drink, crack the lid and let it sit for a few days alongside a control containing the same mass of water. You measure the mass of the cans before and after and calculate the mass lost due to CO2 loss. The control can helps to account for any evaporation, which tends to be most of the loss anyway. Not very exciting and not a lot of CO2 lost.

This time around I tried the salting out method, where you add 1-2 g of salt for every 50 mL of soda water. This causes the CO2 to effervesce immediately, leading to a totally flat bottle in about 10 minutes instead of days. Here are some sample photos:


20140522-165027-60627749.jpgAs you can see, some groups added some universal indicator to see if there was any colour change. The fizz at the top was distinctly yellow-orange, but interestingly the rest of the bottle stayed the same colour. A far more effective method – definitely a keeper!

Engaging the Whole Class with Large SOLO Hexagons

Yesterday my Year 9 class were finishing up our Ecosystems unit in anticipation of quickly moving onto our next unit, Splitting the Atom. We have our half yearly exam coming up very soon so I wanted us to do a revision activity but without spending a whole slab of precious class time on it. Enter the SOLO hexagons!

Now I’ve talked before about using the SOLO hexagon activity in class, with some examples of how I’ve used them. But when I’ve done these activities, I’ve used the small hexagon template and had the students write on the hexagons and cut them out with scissors. The good and bad thing about this, though, is that it can be time consuming to get the students to build solid connections between ideas.

So what I’ve done this time around (with the gracious help of our lab assistant) is to use the large hexagon template (which has 2 per page), cut them out and laminated them. I also had a brainwave and stuck some magnetic tape on the back. The lamination means that you can write on them with whiteboard markers and erase them. The magnetic tape allows you to stick them up onto the whiteboard and make a whole-class tessellation!

I asked the students to write one idea, word, concept relating to our Ecosystems unit and then take turns to put them up on the board, connecting their idea to the ideas already up there. Here’s a photo of their efforts:

20140522-071838-26318864.jpgAt the end we had a few clusters of ideas that I wanted us to recognise, so I wrote those subheadings based on the students’ suggestions.

All up, this activity took 10 minutes tops! Now admittedly we have done the hexagon activity a few times now, so they have some experience and know the format by now, but it was a productive and efficient way to summarise our ideas. There were a lot of ideas not represented (can you tell that we’ve covered the water cycle most recently?) but it was a helpful way to cap things off.

A word to the wise, though – it can be a lot harder to clean marker off laminate than an actual whiteboard!

Too Much Teacher Talk

20140520-071354-26034470.jpgThere’s too much teacher talk in my classroom! I’m feeling frustrated at how much time I spend talking during any given lesson, especially since the talking doesn’t seem to add to the students’ learning at all. I see the glazed looks and distracted chatting and I know I’ve lost them. Sigh.

I know that I’ve mused on this before and I knew it wouldn’t go away completely, but I just reached a point after my lessons yesterday seeing how ineffective it was. But what can I do instead? I already incorporate a lot of student-centred activities and I’ve deliberately structured my room to foster more collaboration, rather than purely facing the front bench. But how do you get students to get information at times when there’s just stuff they need to write down and hear?

Copying some notes off the board and then elaborating on them verbally seems to serve a role here, and I’m proud to say that I’ve done less and less of it this year than in the past. But the glazed looks aren’t exactly comforting or reassuring. What can I do instead?

Chemistry Revision Session

I had a revision session with some of my Year 12 students after school today, working through the gravimetric analysis of sulfate in fertiliser. Below is a whiteboard of the solution I wrote.


Fun with the Van de Graaff!

My Year 8 class were enjoying the Van de Graaff generator this morning!


Acidity of everyday substances

20140515-072513.jpgAs part of our acids and bases module, one activity that the students need to do is to use a range of indicators to qualitatively compare the acidity of different household substances. My Year 12s looked at the following:
Baking soda
Cream of tartar
Hand soap
V energy drink
Kitchen spray cleaner

They used phenolphthalein, methyl orange and bromothymol blue. Here’s their results:


SOLO Learning Intentions and Success Criteria

Today I moved to the next level in my implementation of SOLO (see what I did there?). In my Year 9 class we were revising the concept of food chains and webs, which they covered in Year 8 but now with the Australian Curriculum has become a topic for Stage 5.

We’ve recently introduced SOLO, developing a familiarity with the five levels and completed a survey on attitudes to learning and intelligence and the growth mindset. It was now time to start to introduce the concepts of learning intentions and success criteria.

Learning intentions are a way of articulating to students the purpose and goals of the lesson. I realise that having goals for a lesson isn’t a new concept, but it is an important part of using SOLO in the classroom. They allow students a clear point of comparison at the end of the lesson when they reflect on their learning. If the students know at the start what they are setting out to accomplish, then they can more effectively gauge where their understanding is at at the end.

Success criteria are a way of outlining to the students what success looks like at each of the levels of SOLO, i.e. what does a relational understanding of a particular learning intention look like? Alice puts it really well when she describes them as follows:

…success criteria are what students have to do to be successful in that lesson. The success criteria are classified by the SOLO taxonomy, which lets both the student and the teacher know how the student is progressing and adjust the teaching and learning process accordingly.

Here are my success criteria for this lesson:

The students really seemed to respond to the clearly articulated learning intentions and success criteria. They had a clearer idea of what was expected and what level of understanding they were working at. They were still a bit unsure of what to do – it’s all still very new and there were a number of new factors today – but overall it was very positive.

I definitely need to improve on articulating the strategies that the students can use to achieve success and I think I assumed that they had too much knowledge already. Many of the questions and problems that arose related to knowledge that I had assumed the students had and so I had to backpedal a few times to address this. Nevertheless, the students had a much clearer idea of how to improve and make progress and we’re definitely making positive moves towards adopting the growth mindset. Here’s a sample of one group’s effort that is working at the relational level for this lesson:

Definitely lots to celebrate here!