Target

Families

Thematic

Chemistry

Ciência Viva at home

Kitchen

Keywords

acid | base | bioindicators | pH

Duration

60 min

Typology

Experimental protocol

When we think of a very acidic substance, we usually remember lemon juice or certain oranges. But sometimes, in relation to certain foods, we are not all in agreement; one person may find, for example, a fruit to be acidic and another person may think it is not acidic at all. So that there are no different opinions, chemists use their own numerical scale to quantify the acidity of a given solution - the pH scale. On this scale, the pH value generally varies between 1 and 14. Thus, at room temperature, a solution will be acidic if it has a pH below 7, neutral for pH values equal to 7, and basic if the pH values are above 7.
Substances whose colour changes in contact with acidic, basic or neutral solutions are called acid-base indicators, or pH indicators, and therefore allow the chemical character of the solutions to be identified.

This activity comes under the program #cienciavivaathome. From the kitchen to the bathroom, even walking through the garage, no room was left out: after all, science is everywhere!