Images Dated 27th August 2004

Mercury thermometer

Mercury thermometer showing a room temperature of 24 degrees Celsius. The mercury thermometer works as mercury, a liquid metal, expands evenly as the temperature increases. As it expands it fills more and more of a narrow tube, which is marked with a scale in degrees

© ANDREW LAMBERT PHOTOGRAPHY/SCIENCE PHOTO LIBRARY

24 Degrees Celsius, Device, Equipment, Measurement, Measuring, Mercury, Physics, Room Temperature, Single, Thermometer

JML05103

Assortment of harvested vegetables and garden owner at work beyond globe articokes, zucchini flowers, carrots, tomatoes, pumpkin, leeks, radishes, parsley, cabbage

© Jean-Michel Labat/AUSCAPE All rights reserved

Assortment Of Harvested Vegetables And Garden Owner At Work Beyo, Carrots, Leeks, Parsley, Pumpkin, Radishes, Tomatoes, Zucchini Flowers

Simultaneous contrast

Simultaneous contrast example. The green squares look brighter on the left, where they are in yellow bands, compared to the right, where they are in blue bands. There is no actual difference between them. This is a demonstration of the effect known as simultaneous contrast - the phenomenon whereby the perception of different colours is altered by their surroundings. There has been some debate - most notably amongst the 19th century scientists Helmholtz and Hering - as to whether this results from neurological effects or from retinal pre-processing. It is likely that it is a combination of the two

© SCIENCE PHOTO LIBRARY