Skip to 0 minutes and 0 secondsTEACHER: The white powder is contaminated with sand and soil. So what is our first stage, what do we need to do first? Filter it. So you've got distilled water on your desk. You need to use that water, because distilled water is pure water. OK, you need to filter it, add in 20ml of distilled water, then filter. Once you've got it filtered, you'll need to complete the following tests... You've got the flame tests, with the Bunsen burners around the room. Front tables, if you use the front Bunsen burners, back tables use the back ones. Carbonate test, add in hydrochloric acid. Halide test. And the sulphate test.
Skip to 0 minutes and 52 secondsYou need to record all your results on the table you've been given, then tell me what the compound is and why, and who is your suspect. First things first, you need to stand up, get your goggles on, you're going to work in pairs on your desks, all the chemicals are on your desk. [Classroom conversation]
Skip to 1 minute and 20 secondsTEACHER: What colour has it gone?
Skip to 1 minute and 32 secondsSTUDENT: Lilac.
Skip to 1 minute and 34 secondsTEACHER: So lilac means it is...
Skip to 1 minute and 35 secondsTEACHER: Get one of the test tubes and add hydrochloric acid... you can turn your flame off now.
Skip to 1 minute and 44 secondsTEACHER: Fantastic. So we'll write that as our conclusion.
Skip to 1 minute and 52 secondsBrilliant, so we're not contaminating anything, well done.
Independence within the lab space
Getting students to work independently in the lab can be a daunting task as you need to know they are confident with the equipment they are using, and undertaking the method with little guidance. Similar to practical routines, the skills to be independent can be built up over time, so starting with younger students will ensure you reap the benefits later.
Independent work also allows students to take more ownership of their work. It allows students to discover links between topics and other work they might have covered, as they have to recall and draw upon knowledge from previous lessons. In the video above, students are asked to apply their understanding from the curriculum to solve a crime scene scenario. The teacher has provided the context, and the intended outcome which is to identify an unknown substance. Students are provided with equipment and asked to record results.
Example of independent enquiry
Another good example of this was when we visited a school and the teacher was beginning the topic of waves. The students came in and on the side of the lab were a set of empty trays, some metre rules and stopwatches. The teacher had already organised the class into groups of three, so when he asked them to get with their group they did so immediately. They then asked the groups to find the speed of a wave using the three pieces of equipment, and that was the only instruction provided.
After a minute of slight confusion and bewilderment, the groups started to discuss how they might go about this and off they went to fill the trays with water. Nearly each group performed the experiment differently and got a result using a variety of methods. With there being no ‘correct’ answer, the focus on the practical was not for students to ‘be correct’, but for them to demonstrate how they were linking concepts from motion such as speed = distance / time, to the waves topic.
The discussions that came from this activity allowed the students to demonstrate their understanding and they came away with a deeper appreciation of practical work. They wanted to have more independence in future practical work too, which then would benefit them further, and they could link it to work they did later too.
Watch the video of practical work lesson again. Identify what actions the teacher has taken to enable students to complete the practical work independent of support. Consider the actions required before, during and after the practical to support learning.