 We're going to tell you about topography and show you how to use an inclinometer, which measures the incline of a hill or mountain. That's right, topography is all the features and forms of the land, like ridges, mountains and valleys. Topography can give you clues about how a bushfire might behave as it moves across the landscape. Did you know that fire spreads faster uphill than it does downhill? Basically, the speed of the fire doubles with every 10 degrees of slope or incline. So if a fire is moving at one kilometre per hour and gets to a hill that has a 10 degree slope, the fire speeds up to two kilometres per hour. And the opposite is true for a fire travelling downhill. So if the fire is moving at one kilometre per hour and gets to a downhill slope of 10 degrees, the fire slows to half a kilometre per hour. As you can see, it is important to know about topography, including the incline of an area. So how do you work out the degree of incline of a hill or mountain? Or Sarah, you can use an inclinometer. OK, that's great Eli, but how do you use it? To use the inclinometer, find a partner the same height as you and ask them to stand at the bottom of a hill you want to measure. Put the inclinometer up to your eye and close the other eye. When you look through the hole, you will see a red line and numbers. Align the red line with your partner's eyes. The number next to the red line is the incline, and that is how you use it. OK great, so when do I use it? You check the incline of a hill before summer so that you know how fast a fire will travel if one starts. This can help you know when to evacuate, and you are much safer in a valley than the top of a hill. So who uses an inclinometer? People who need to know the topography of the land use an inclinometer. Hikers may use it, any builders or excavation crew may use it, but most important, firefighters use it to predict fire behaviour. Cut. Can we do that again?