pondweed

Everyday

A plant that grows in ponds and slow rivers, often under or on the water, with green leaves or stems. tree →

In the lessons

In science lessons, pondweed (often Canadian pondweed, Elodea) is used in experiments on photosynthesis: put it in water under a lamp and count the oxygen bubbles. Pondweed gives food, shelter and oxygen to pond animals like tadpoles and snails. In stories, pondweed is slimy and tangly. Phrases: «count the bubbles», «pondweed experiment», «covered in pondweed».

Examples

• We counted the oxygen bubbles coming from the pondweed. tree →
• When the lamp was closer, the pondweed made more bubbles. tree →
• Tadpoles hide in the pondweed. tree →
• The frog jumped out covered in green pondweed. tree →
• Too much pondweed can choke a pond. tree →
• Our class pond has lots of pondweed. tree →

Note

Usually uncountable («some pondweed»); «pondweeds» for kinds. One word. In the experiment, more light means more bubbles (more photosynthesis) up to a point — a fair test changes only the distance of the lamp.