The Snowball earth

So today's lesson was about the ancient climates. One of the additional reading mentioned was this: snowball earth After reading this - I was intrigued the research is quite recent (1998) - and Namibia (which is adjacent to my home country, South Africa) played a crucial role in this. I searched the timeline of the earth on Google and found this: The history of the Earth So the 600 Million years ago there was an Ice Age - actually lined up pretty well with the Biological evolutionary Data. It is truly fascinating. I've created a board to illustrate how this happened. I'm still uncertain about the "chemical weathering" part. My snowball earth

The Blanket Analogy

In the opening video the lecturer says the greenhouse analogy isn't really good, and that the blanket analogy should rather be used. I disagree strongly. The blanket analogy has the same problem as the greenhouse and more (being opague). He says "The problem is that what really warms the greenhouse up is the prevention of air flow, stopping the loss of heat by convection." Similarly, the blanket stops airflow over the body - stopping the loss of heat by convection. Also a blanket is really conduction related insulation and the problem is radiation, not convection or conduction. So, if you have a blanket over you - you have a twofold advantage over being naked - firstly the blanket provides a thermal insulation that prevents heat flow through conduction. The second advantage is that you don't have air flowing over your body at a quick rate, so the convection heat loss that you have is lower.