Heat ¦ Light

Life depends on light' asserts the author in Light's terminal sentence. Who but a blind Mexican cave-fish would disagree? Preceding this statement come 22 pages of excellent low-density text and high-topicality pictures starting with 'the biggest light of all - the sun - and going on through other light sources, light waves and their straightness, transmission, reflection, colour and photosynthesis.

Heat does the same job for radiation, convection and conduction, and brings in insulation and the changes wrought by heat. Both volumes are distinguished by their author's effectively simple style - 'insulation works like a duvet to keep the house warm' (well, who knows about tea-cosies these days?) and 'darkness falls because the sun cannot shine through the earth'. And the pictures help the text no end - returning to insulation, we find that the two men installing fibre-fill in a new house are insulating themselves with quilted waistcoats.

Such a combination of text and illustrations is a happy one and, for once in the long succession of 'science starters', it ensures that these not only look suitable for infants but actually are.