British Sign Language Glossaries of Curriculum Terms

BSL Environmental Science Glossary - Tüllgren funnel definition

Definition: Tüllgren funnel is a piece of equipment used for extracting invertebrates from soil or leaf litter. The funnel consists of a mesh, and you put soil or leaves (with invertebrates) on the mesh. A glass bottle is used to trap the insects from below. The lamp will heat the soil, and the top layer will dry. Invertebrates prefer soil with moisture, and they will move downwards away from the dry soil. Over time, the soil will become drier and drier. This will cause the invertebrates to go down further and fall through the mesh into the bottle. We usually put water or alcohol in the bottle to trap the invertebrates. This method will enable us to know which invertebrates are in the soil.