How do stinging nettles sting you? - practical biology experiment 🌵🧪
Channel: Science and Plants for Schools
Date: 2013-09-12

In this quick and easy classroom practical, students investigate stinging nettles leaves to discover how they are adapted to deter herbivores, while also consolidating chemistry concepts around acids, alkalis and the pH scale. After identifying the adaptations from a range of leaves, students go on to investigate the pH of nettle stings using Universal Indicator paper.

Stinging nettles have developed stinging cells as an adaptation to deter herbivores from eating them. The plants contain long, thin, hollow hairs that cover the majority of the stem and the underside of the leaves. Nettle stings contain acid (formic acid) but they also contain histamine and other chemicals; it is the histamine that causes the initial reaction when you are stung. Dock leaf sap contains a natural antihistamine, which helps to ease the stinging sensation. The dock leaves themselves contain oxalic acid, which deters herbivores from eating them.

This activity can easily be built up into a broader investigation, or used as a quick practical to introduce the topics of plant defences, adaptations and specialised cells.  

0:00 Introduction
0:24 The stinging mechanism
0:48 Experiment practical - step-by-step
1:55 Link to SAPS resources

Download the full student sheet and teacher's and technical notes free from the SAPS website:
http://www.saps.org.uk/secondary/teaching-resources/869

#scienceexperiment #stingingnettle #schoolscienceproject