Some evenings the sunset is stunning while on others it is only so-so, even though the sky is cloudless in both cases. What causes the difference?Ben Wagstaff, Northallerton, North Yorkshire, UK
In hot weather dogs keep cool by panting. If I were to do this I would hyperventilate and exhale too much carbon dioxide. How do dogs avoid the effects of respiratory alkalosis?Andrew Benton, Birkenhead, Merseyside, UK
Where on our planet is the furthest point from any sea? I'm hoping it is in the middle of Asia somewhere because I'm travelling that way soon, and want to stand at that point in swimming trunks, snorkel and mask.Hugh Jones, Slapton, Northamptonshire, UK
On a long motorway journey while driving behind a horsebox, I wondered, do horses get travel sick? In fact, do we know whether any animals besides humans suffer from motion sickness?Neil Bowley, Newthorpe, Nottinghamshire, UK
I found these icicles (see Photo) hanging from small branches leaning over a creek. The ends were mainly shaped like suction cups - slightly concave at the bottom - although a few icicles sported a spherical end. The water beneath was flowing, and the temperature was around -12 °C. How did they form?Sandor Frecska, Mannington, West Virginia, USA