If you are taking your GCSE Chemistry exam next week, you may be revising moles and calculations. The concept of moles in chemistry can be tricky. Unlike the moles found in the garden, which people often think of as blind. However, moles can actually see, just not very well. Why not take a little break from revision, and read all about some animals which cannot see at all.
First up is the blind flatworm, a parasitic worm which lives in the intestines of mammals. Even though they have no eyes, these worms are able to locate animals to infest, by following a light intensity gradient. Two bumps on the worm’s head sense light – guiding them towards their unknowing hosts!
Next on the list is the eyeless shrimp, not discovered until 2012! Scientists found them living in deep volcanic sea vents, surviving scalding temperatures. Even more weirdly, the shrimp are actually born with eyes, losing them as they become adults. Once adults, a sensory organ develops allowing them to use infrared radiation to find their way around.
Last , but definitely not least on the list today, is a species of huntsman spider which lives in caves. Most spiders have eight eyes, but this species, found in a cave in South East Asia has none at all! Living in complete darkness, they have little need for eyes!
If you are studying GCSE science you need to be able to complete calculations with moles, and masses. For help with this try our new revision guide “How to work with Moles and Calculations”. It explains how to calculate relative formula mass, how to use the moles/mass/formula mass equation, and how to calculate the number of atoms in compounds. Included are questions to try, and answers to check your understanding.
To see the guide click the picture below.
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