Right now mountains are being moved! They're being moved very very slowly but it's still quite an exciting thought. Ice is incredibly powerful. Water can get into every tiny crack and crevice, so when it freezes and expands, it can split huge rocks into pieces and even slowly break down mountains.
Moving ice can change whole landscapes. During the Ice Age, when the climate was a lot colder than it is now, about a third of the planet, including the UK, was covered by a massive sheet of ice. Over thousands of years, these enormous rivers of ice (known as glaciers) moved very slowly across the landscape, dragging huge boulders and stones with them, carving out valleys and leaving behind piles of stones and rocks. You can sometimes see big, lonely boulders perched here and ther which would normally be found thousands of miles away! These are called erratics.
At the end of the Ice Age, as the climate warmed up and the ice began to melt, there was so much water around that sea levels started to rise, cutting off chunks of land and creating islands like Britain and Ireland. Some animals got left behind when this happened, and that's why you won't find any weasels, snakes or tawny owls in Ireland.
Water turns into ice when the temperature drops below 0 degrees Celsius (or freezing point) but what actually happens? Water is made up of miniscule pieces called molecules which are too small to be seen, even under a microscope. These molecules move around all the time while the temperature is above freezing. Once things start to cool, the molecules slow right down. That's when liquid water becomes solid ice.
Water expands when it freezes but although the ice takes up more room than water, it's actually lighter. As ice weighs less than water, it will float. In winter, the floating ice on a pond or lake traps warmer water underneath. Fish and other creatures, such as hibernation frogs, buried in the mud at the bottom, can survive the cold weather.
After a freezing cold night of frost and ice, you might notice that some plants that have been growing in your garden during the summer, such as brightly-coloured nasturtiums, will turn brown or just flop over. These are usually plants that come from warmer countries and cannot survive our winter temperatures. Plant cells in the leave and stems are full of water, so when this freezes and expands, the delicate cell walls break down and the plant dies.
Plants that normally live in colder climates are much tougher, and they have a clever way of surviving the winter. They produce lots of sugar, which stops the water in the cells from freezing. In fact, people who grow brussels sprouts and parsnips like the frost because it makes the plants produce sugar so they taste sweeter. Some seeds and plant like hawthorn and apple trees actually need to go through a spell of icy weather before they can start to grow or germinate. This is called dormancy and it protects the seeds so they don't start growing before the warmer days of spring. If you want to grow these seeds indoors in a warm house, you have to put them in the fridge for a few weeks first so they think it's winter!
Experiment - you can see for yourself how ice breaks down plant cells: out a small, firm, fresh tomato in the freezer and leave it there for a few days. Then get it out and let it thaw. you'll see that it's now gone soft and squidgy. This is because when the water inside the tomato froze and expanded it burst the cell walls that kept the tomato firm. You can still eat it though, it will taste just fine in pasta sauce or soup.
One of the most exciting times to go out looking for wildlife is the the hour before darkness. At this time of year this is around the time you've just finished your tea. So take a brave adult and go on a journey into the unknown.
Most mammals are active at night , rather than during the day. They come out at dusk and they will be hungry after sleeping all day. Tuck yourself somewhere along the edge of a field or park where you are less likely to be seen. Stand quietly and see what you can spot.
Nervous bunnies - There might be rabbits scuttling about when you arrive, nibbling grass and chasing each other. They can see all around them in the daylight and there are many bunny eyes watching for predators. But as the light fades, they seem to get nervous. For a rabbit, danger lurks in the shadows. You might just find out why the rabbits are scared. See if you can spot a fox prowling aroudn teh degge of teh field. Foxes patrol thier territory every night, hoping to strike it lucky.
Out in the open - You might see a deer walking out into the open. It's been sleeping in the wood - perhaps under a bramble bush. Now it will be eating grass aor plants in the field. You might see a roe deer, or, if you live in southern England, the smaller muntjac is just as likely.
What, no colour - Something amazing happens while you're watching and you don't quite realise it. Everything turns to black and white. That's because your eyes need bitght light to see colours. Cells in your eyes called cones can tell one colour from another. As it gets dark, they stop working. The grass looks grey instead of green adn even your colourful clothes are now different shades of grey.
The ghost hunter - One creature stands out in the murky world. The barn owl is so dazzilingly light that you can see it even as darkness falls. Over field it flies, broad wings beating silently. It's worth braving the darnesss to catch a glimpse of this amazing bird.
Don't forget, there's only 3 more days to submit your results for the 'Birds and their song' WildSquare survey. Our next survey starts on Thursday and is all about the signs of spring.