2. Drawing diagrams to explain science
In science we often illustrate key ideas by drawing diagrams. The temptation is to get the students to copy the diagram off the board so that they learn the ‘right’ version. In Activity 2, you are encouraged to let the students draw their own diagrams to illustrate the forces involved in three demonstrations. Resource 3 provides the necessary background. The case study shows how one teacher managed this in her classroom. During the demonstrations, you should prompt students to ask questions about what is happening. The act of asking questions requires engagement and creative thought, which is what we are trying to promote. You will also find that the students are more interested in the answers to questions that they have generated. Resource 4 provides information on how to promote an atmosphere of enquiry in which students are encouraged to ask questions.
Case study 2: A Bungee jump
Miss Chitsulo was a student teacher on teaching practice. Her tutor was coming to visit in order to watch her teach. Miss Chitsulo knew that her tutor had a laptop computer so she asked her to bring the laptop and a projector from the college to the lesson. The week before, she went to an internet café and downloaded a film of someone doing a bungee jump from the bridge across the river Zambezi and stored it on a memory stick. In the lesson, she gathered the class around the front and showed them the film of the bungee jump. Miss Chitsulo asked lots of questions about what they thought it would feel like at each stage. She sent the class back to their places to draw diagrams to explain what they had seen.
They had to draw three diagrams of the bungee jumper to show the forces acting at various points in the jump – on the way down, at the lowest point and on the way back up. The class teacher suggested that they should copy the diagrams off the board, but Miss Chitsulo wanted to see if they could do it themselves. While they were working, she walked round the room and asked questions to prompt them to remember the discussion they had had. At the end, she asked volunteers to draw their diagrams on the board and gave everyone the chance to correct their own work. She chose people who she knew had got it nearly right. Her tutor also walked round the room and talked to the students. She was impressed by some of the questions that they asked.
Activity 2: Student-led demonstrations
In this activity, you will do three demonstrations: a spring balance (a newton meter) with a mass in water and in the lab; pushing a balloon into the water and a floating needle. See Resource 3 for the details. Give the students the opportunity to volunteer to contribute to the demonstrations. Get the students to generate a set of questions about each demonstration. Write these on the board and discuss the answers as a class. Students should then be asked to draw pictures of each demonstration (or label pictures you have provided) using arrows to illustrate the forces acting. It is important to let your students draw the diagrams for themselves. Don’t worry if they make mistakes – they will learn from the mistakes and are more likely to remember if they have thought about it for themselves. At the end, draw the correct diagrams on the board and ask them to correct their own.