4-4.5 Carry out the procedures for data collecting and measuring weather conditions (including wind speed and direction, precipitation, and temperature) by using appropriate tools and instruments.
Measuring Weather Conditions
Essential Question: How do instruments help us to measure weather? Scientists study conditions by using weather tools to take measurements. These data help them understand and compare weather conditions. Measuring Temperature Temperature is a measure of how hot or cold something is. You can use a thermometer to measure the temperature of the air or some other material. A common kind of thermometer has a liquid inside a thin glass tube with numbers next to it. When the liquid gets warmer, it takes up more space, It rises in the tube. When the liquid gets cooler, it takes up less space. It sinks in the tube. To find the temperature, read the number next to the top of the liquid. The scale on the thermometer may be in units of degrees Fahrenheit (F) or Celsius (C), or both. Measuring Precipitation Recall that precipitation is water that falls from clouds. It can take the form of rain, snow, hail, and sleet. To measure rainfall, weather scientists use a tool called a rain gauge. This tool is a can or tube with an opening on top. Rain falls into the rain gauge. Marks and numbers on the side show how much rain has collected in it. Most rain gauges show rainfall in inches. Measuring Wind Speed and Direction Remember that wind is moving air. An anemometer measures wind speed – how fast the air is moving. This took has several arms that stick out from a center rod. Each arm has a cup at its end. Wind blows into the cups and spins the anemometer. The anemometer counts how many times it spins in a given period of time. The faster the wind blows, the faster the anemometer will work properly. A wind vane, or weather vane, shows wind direction—where the wind is coming from. You may see wind vanes on the roofs of houses or barns. A wind vane spins freely. It points in the directions from which the wind is blowing. If a wind vane points to the east, the wind is blowing from the east. Wind coming from the east is called an east wind. A compass is used to find north, south, east, and west. You can use a compass with a wind vane to find wind direction. A compass can tell you in which direction the wind vane is pointing. |
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