11. Indigestion

Which indigestion remedy works best?

Indigestion remedies react with acid in our stomachs and cancel it out. We can test different indigestion remedies by reacting them with some dilute acid and measuring the pH of the mixture after it stops reacting.

Planning

1 When you plan your experiment you should think about these things:

• What apparatus will you use?

• How many different indigestion remedies will you use?

• Which factor(s) will you keep the same in each test?

• What will you measure each time?

• How will this tell you which is the best indigestion remedy?

• Will you add the solid to the acid, or the acid to the solid?

• How much of the indigestion remedy will you use?

• How much acid will you use?

• How will you test the pH?

• When will you test the pH – before adding the remedy, after adding it, or both before and after?

• What will you do to make sure that this is a fair test?

• What will you do to make sure that it is an accurate test?

Safety and risk assessments

2 What do you need to do to make sure you are safe?

• What are the possible dangers in this experiment?

• How can you control the risks?

Get your teacher to check your plan before starting the experiment.

Predicting

3 Explain how your test will work and what will happen to the pH.

4 Is it possible to make a reasoned prediction about which remedy you expect to work best?

Recording your results

5 Design a results table to record your results.

Considering your results/conclusions

6 a What happened to the pH when the remedies reacted with the acid?

b Was this what you predicted?

7 a Which remedy worked best?

b How do you know?

Evaluation

8 Can you suggest improvements to the way the experiment was done, to make the results more precise?