LESSON PLAN 1

Aim: To make an introduction to acids, alkalis and indicators; to discuss hypotheses.

Teaching objectives

Content

• Indicators

Communication

• Use of ‘perhaps’ to make hypotheses

• Interpreting data and writing conclusions

Cognition

• Remembering the steps of an experiment

• Analysing and evaluating hypotheses

Outcomes:

At the end of the lesson, students will be able to

• know that acids and alkalis have different effects on indicators

• recognise the importance of hypotheses in science
• draw and recognise sketches of laboratory tools and experiment steps
• know scientific vocabulary
• make hypotheses and discuss them with team members
• write conclusions concerning an experiment
• present and defend an argument
• understand the result of an experiment
• develop criteria for judging the value of a hypothesis

Tasks planned and timing

• Power Point to introduce the subject: what it is about; that it will be taught in English; and the topics that will be explained (5 min)
• The teacher will perform an experiment: he will water a white flower with two sprays; with the first one, the flower will turn pink, with the second one, the flower will turn back to white (5 min)
• Students will be provided with two sets of cards: one set depicting 5 hypotheses to explain why the flower changed its colour, the other set with the same written hypotheses, all of them starting with ‘I think that perhaps the flower changed its colour because…’. Working in pairs, students will match each picture with a sentence, and then will have to discuss which two hypotheses they think are more likely to be true (10 min)
• Once they have chosen two hypotheses, students will be asked to decide which one is the true one performing a small investigation on the flowers and the sprays. They will be provided with a handout to write down evidence supporting and refuting their hypotheses, and they will have to write down their conclusions (20 min)
• Plenary: the conclusions of each team will be presented to the rest of the class (10 min)
• Power Point: which of the hypotheses is the true one and why, introduction to indicators and their effect with acids and alkalis (10 min)
• Homework: a handout to draw the steps of the experiment, a handout to remember the effects of acids and alkalis on indicators

Resources

• For the power-point: a computer, a screen and a projector

• For the experiment: three white flowers, the best ones are white carnations; a spray with an alkali solution inside (bleach); a spray with an acidic solution inside (vinegar); phenolphthalein. The carnations should be previously watered with phenolphthalein, before the beginning of the class
• For the hypotheses activity: two sets of 5 cards for each team, one with drawings, the other one with sentences; a handout for each student to write down evidence supporting and refuting the hypotheses, and to write down conclusions
• For the homework: two photocopies for each student

Assessment

• Homework will be suitably marked

• In the plenary, students will be asked to assess each other

Evaluation