1. Focus on language to support understanding
Researchers have established a clear link between language and learning. When students discuss ideas with peers, they have time to draw on their memory of what they have done before, share ideas with their partner and clarify their thoughts by having to explain them to others. It also helps them to get used to the scientific words, which might not be familiar to them. You get the chance to listen to what they are saying and look at what they are writing, so that you are aware of their misconceptions when you plan your questions at the end. You are far more likely to address their misconceptions in this way. Too often when we use questions in a whole class discussion, we assume that because one student can give us a correct answer, the class as a whole understands the topic well.
Activity 1 will take more time than simply explaining cell structure to the whole class and asking them to copy labelled diagrams and notes. However, it will help the students to understand.
Case study 1: Creating a word wall
Mrs Keraro worked in a secondary school in Moshi, Tanzania. She was concerned that her 13-year-old students found scientific words difficult to pronounce and remember. She created a ‘word wall’ in the classroom. Every time they started a new topic she wrote the key words on card from an old cereal packet and stuck them on the wall. Whenever she had 5 or 10 minutes to spare in a lesson, she would play a game with her class. One person pointed to a word and someone else had to say it and explain the meaning. Alternatively, she divided the class into teams. She would say the meaning and one person from each team had to run to the wall and point to the word. She encouraged her students to make up different games. At the end of the year, their understanding of scientific words had improved a great deal.
She did this with the cells topic; she put up the technical words like ‘chloroplast’ and ‘membrane’, but also the easy words like ‘cell’ and ‘cell wall’. This is because she thought her students might think they knew what a ‘cell’ was – a small room where a prisoner is kept! Lots of scientific words have different meanings in real life and she knew that this often confused her students. She also put up two large photographs of cells as seen using a light microscope. She asked the students to look carefully at the pictures and to talk about them in their pairs. During their discussions, she asked them to write down three interesting observations about the object in each photo. She also asked them to think of two questions which they would like to ask about each of these objects.
Activity 1: Working in pairs to discuss cells
Before the lesson, draw diagrams of generalised animal and plant cells on the board, without labels. Ask each student to copy the diagrams. Also, on the board write the names of the main structures (see Resource 1). Tell pupils to work in pairs or threes to label the diagrams and annotate them with the functions of each part. No one is allowed to write in the label or the function until they all agree. Talking about the answers will help them to learn. While they are working, move round the room. Visit the back of the room first. When you discuss the labels, your initial questions will mainly focus on recall, but try to follow these up with a more demanding question. You could check their understanding at the start of the next lesson by using the true/false exercise (Resource 2). Again, let your students work in pairs and discuss the answers.
Section 5 : Cells
2. How big are cells?