Do vitamin pills work? Exploring scientific evidence | 14-16 years

In this activity, students discuss and explore issues surrounding the well-believed fallacy that taking vitamin C prevents colds. They analyse original data from Linus Pauling’s work in the first part and consider a range of views about taking vitamin pills in the second part.

Learning objectives

Students will recognise that

• Science does not always produce clear-cut answers.
• Data may be interpreted in more than one way.
• Scientific knowledge can be used when discussing different viewpoints.

Sequence of activities

Introduction

Introduce the topic by asking students if they have had, or know someone who has had a cold recently. Ask if they think taking vitamin C would have helped the cold in any way. Record their views for later reference. Indicate that they are going to look at evidence about vitamin C preventing colds.

Catching a cold? stage 1

Give each student a copy of the sheet ’Catching a cold?’ and ask them to look at task 1.

Circulate and support the students working individually on answers to the first three questions.

Catching a cold? stage 2

Organise students into groups of three or four to work on Task 2. Circulate and support as they:

1. Share their answers to questions 1‑3.
2. Agree on answers to questions 4‑6.
3. Elect a spokesperson to give responses to the whole class.

Plenary 1

In a plenary:

1. Hear the responses from the spokespersons.
2. Review the answers.
3. Try to reach agreement about the data and the role of vitamin C in preventing colds.

Full agreement is not needed – recognition of different interpretations of the data is needed.

The pill thrill: are vitamins a waste of money?

Explain the next task, to consider different viewpoints about taking vitamin pills. Distribute, to each student, a copy of ‘The pill thrill: are vitamin pills a waste of money?’

Give each group a set of the four cards, and support them as they:

1. Consider each of the different views on the cards.
2. Agree rankings for each viewpoint from 1 (most agree) to 4 (least agree). Students should follow the same process:
   • Each viewpoint must have its own ranking.
   • Each ranking must be agreed by all group members.
   • Each ranking must be accompanied by reasons, preferably scientifically based.
3. Elect a spokesperson (different from earlier) to give the group’s views to the class.

Plenary 2

In a plenary:

• Invite spokespersons to contribute their group’s rankings with their reasons.
• Encourage students to listen to each other and debate different opinions fairly.

Feedback

Collect in the worksheets to review the quality of students’ reasoning. Give written feedback that helps students to see how they can improve their reasoning skills.

Commentary

This activity explores science as an activity that, contrary to popular belief, does not always produce ‘right’ answers. Stimulus material involving data analysis is designed to provoke discussion and debate, encouraging students to listen to alternative viewpoints that may challenge their own ideas. This will help shape their thinking.

Teacher feedback can focus on the extent to which students have acknowledged that science is not always clear-cut and that some things we accept as ‘fact’ are only hearsay. Students may need extra support to help them recognise this.

Answers

From ‘Catching a cold?’:

1. So they could not ‘cheat’ by making sure the results fitted with the type of tablet.
2. a. 51.61%, b. 34.45%, c. 37.50%
3. The data suggests that the vitamin C group had fewer colds and symptoms than the blank group.
4. a. headaches, diarrhoea, general body weakness, stomach pain
   b. the blank group could have been living higher up the mountain, so were more prone to headaches; eaten a bad meal; lived more closely together so transmitted infection more easily; one or two people could have been very ill with many symptoms skewing the results.

All other answers are subject to students’ and teacher’s discussions.