What factors would you discuss if you were on a panel that supported the idea that climate change is due to human activity?
I would discuss the "greenhouse gases", which trap heat on the Earth's atmosphere and warm it up: firstly, increased carbon dioxide levels, caused by burning fossil fuels, cutting down rainforests, and increased urbanisation. There are also increased levels of methane and nitrous oxide in the atmosphere. These are thought to be due to increased agriculture and the use of fertilisers, as well as being given off by waste in landfill sites. I would also discuss the hole in the ozone layer, a layer of ozone gas which is concentrated at the poles and is responsible for mediating the effect of sunshine on Earth's temperature. Fluorocarbons were the first gases identified as affecting the ozone layer, and although they are being phased out, they still have a detrimental effect on this layer.
What is paper chromatography, and why does it work?
Paper chromatography is the separation of different coloured substances in a liquid mixture using absorbent paper such as filter paper. It works because each substance has a different weigh and dissolves at a different rate. The substance which is lighter in weight will move more quickly up the piece of paper than a heavier substance.
What are three physical differences between predator and prey animals, and why do they suit each type of animal?
Predators have sharp, strong biting teeth for catching and eating prey, while prey animals have flatter teeth and sometimes no top teeth, for biting plants and grinding them up. Predators have forward-facing eyes to focus sharply on their prey. Prey animals have eyes on the sides of their heads, so that they can see in as many directions around themselves as possible, so that they can run away from predators as early as they can. Predators tend to have small, pricked- up ears to help them find direction. Prey animals tend to have big, wide ears to collect as much sound as possible and alert them to the presence of predators coming closer.