Unit 10 Common Acids and Alkalis

Topic

The living conditions of aquatic animals

Curriculum Link

2.1 Living things: characteristics of living things
10.2 Indicators for testing acids and alkalis: pH scale

Estimated Lesson Time

80 minutes

Introduction

Animals are sensitive to the environment for their survival. For example, aquatic animals relies on the good water quality for feeding, reproduction, etc.

In this activity, students will explore the main conditions (e.g. water temperature, oxygen content and pH).which are very significant for the survival of aquatic animals. In particular pH, students will understand what they learnt in Unit 10 is related to our daily life. For oxygen content, students should know the need of respiration in Unit 7. For water temperature, teacher can briefly introduce its effect on the metabolic reactions of living things.

Key Question

What are the suitable living conditions for aquatic animals?

Learning Objectives

In this activity, the students should be able to

  1. recognise different conditions and their significances for the survival of aquatic animals;
  2. design an experiment to find out the effect of pH on the survival of brine shrimp (SP 3);
  3. analyse and interpret data to draw a conclusion (SP 5);
  4. present the data in form of a graph (SP 6);
  5. recognise the limitations in a scientific study.

Teaching Plan

Task (Time) Brief Description Materials Objectives

Engagement
(10 min)
  • Students are engaged to share their aquaculture at home.
  • Teacher introduces the simple set-up of an aquarium and ask students to observe and explain the apparatus in the video which is useful for good water quality.

    https://www.youtube.com/watch?v=bz64jidOdLw
 (1)

Exploration
(25 min)
  • Students explore the effect of pH on the survival of brine shrimp. They are required to design an experiment to study such effect.
  • For more able class, teacher can cross out the material list and let students think themselves.
  • Teacher guides students to explore the manipulation of water quality:
    • constant oxygen content by air pump
    • constant water temperature indicated by thermometer
    • constant food supply (yeast solution)
    • varying the pH by using baking soda solution (1%) and vinegar (1%) which do not harm the shrimps
  • The aquaculture of brine shrimp is simple and students can try out their designs at home.
 (2) & (3)

Explanation
(30 min)
  • Teacher instructs students to present the data by drawing a graph.
  • Students analyse and interpret data to explain the effect as well as draw a conclusion.
(4)

Evaluation & Elaboration
(15 min)
  • Teacher guides students to evaluate the design of set-up.
  • Teacher explains the significance of large sample size and the concept of experimental error.
  • Students elaborate the best pH as well as other survival conditions for the shrimp.
 (5)

*Apparatus and materials required: