Unit 6 Matter as Particles

Topic

The change of potato

Curriculum Link

3.1 The basic units of living things: basic structure of a cell
6.2 Illustrations for the support of the claims of the particle theory
6.3 Particle model for the three states of matter

Estimated Lesson Time

80 minutes (additional 20 minutes for the experiment)

Introduction

In this activity, students will explore the movement of particle in a biological system. Potato is selected and placed in different medium. Its mass is traced to stimulate students to relate the change in mass to the particle theory. In addition, students will be asked to illustrate the particle arrangement of potato cell with reference to particle model.

Key Question

Why does the potato change?

Learning Objectives

In this activity, the students should be able to

  1. make the hypothesis of the change in potato in a daily life examples and testify the suggested ideas with scientific method (SP3);
  2. present the data in a form of table (SP6);
  3. analyse and interpret data (SP5);
  4. apply the particle theory for explaining the phenomenon related to potato cell;
  5. apply particle model for illustrating cell structures.

Teaching Plan

Task (Time) Brief Description Materials Objectives

Engagement
(10 min)
  • Before the lesson, teacher should prepare several pieces of raw potato already immersed in distilled water for 30 minutes (or longer) as well as raw potato without treatment. Record the mass of the raw potato.
  • Teacher engages the class by circulating the two types of potato and allowing the students to sense as well as describe the texture of potatoes.
  • Teacher provides the mass of the raw potato.
  • Teacher asks the students to compare the potato and suggest an explanation for the difference.
 (1)

Exploration & Explanation
(25 min)
(additional 20 minutes for the experiment)
  • Students design an experiment and explore the reason that the potato absorbs water.
  • Teacher can opt to conduct the experiment. As it takes time for the data collection, teacher can go through Q3 of the worksheet first and then Q2 (described as below).
  • If teacher will not opt to conduct the experiment, the teacher should do it before the lesson and provide the students with the data for discussion during the lesson.
 (1)

Explanation
(25 min)
  • Students construct a table to present the data collected.
  • Students analyse and interpret the data of mass change in potato and water.
  • Teacher guides the student to explain carefully with reference to the particle theory.
 (2) & (3)

Elaboration & Evaluation
(20 min)
  • Students elaborate another case related to particle movement and particle model. Teacher evaluates students' understanding of these two concepts.
  • Students draw the particle arrangement in a biological system.
  • Teacher reminds the requirement of a biological drawing.
  • Teacher explains the structure of the cell:
    • cell wall is rigid and cannot be distorted.
    • the cytoplasm loses some particle, so the cytoplasm will shrinks and the cell membrane will then be pulled and detach from cell wall.
  • Students distinguish matter states of cell wall (solid) and the matter in the space (liquid) as reflected in their drawing on the particle arrangement.
 (4) & (5)

*Apparatus and materials required: