When the mercury or needle in a barometer rises, it means the weather is sunny and dry. When the mercury or needle in a barometer falls, this means the weather will be stormy and wet. [3] X Research source
A small, empty coffee can Plastic wrap A pair of scissors Tape A straw An index card A rubber band
High pressure will cause the plastic wrap to dip, leading to a rise in the straw. Low pressure will cause the plastic wrap to puff up, leading to a drop in the straw.
Wind speeds are typically measured using the Beaufort Wind Scale, with a 0-12 scale based on visual cues. You can learn to identify calm, gentle, moderate, and strong breezes with your homemade anemometer.
4 plastic cups of the same color, such as Dixie or Solo cups 1 plastic cup of a different color 2 long strips of stiff cardboard A pen A pencil with an eraser on one end A ruler A stapler A push pin A watch with a second hand or timer A small fan A calculator
Use the scissors to poke a small hole in the bottom of the remaining cup. Slide the pencil into this cup. The anemometer should now stand upright, supported by the pencil in the cup. There should be 4 cups on the ends of the cardboard pieces, all on their sides and facing the same way.
Use the different colored cup as a marker for 1 rotation, where 1 rotation is every time the different colored cup comes all the way around. This will help you to count the rotations accurately. You can also test the anemometer outside to get an air pressure reading. Make a chart that has 2 columns, 1 for the time interval and 1 for the number of spins. You can then record the time interval and the number of spins within that time interval.
Relative humidity is the ratio of water vapor in the air relative to the amount that could possibly be there, at a certain temperature. When you walk through fog, for example, you are experiencing 100% humidity. If you walk through a desert, you are experiencing around 10% humidity. [10] X Research source
Cotton gauze, in pads rather than balls A pair of scissors A small rubber band A ½ liter empty plastic soda bottle Clear plastic tape 2 red alcohol Celsius thermometers Water An 18 in (46 cm) piece of string
Cover 1 bulb of the thermometers with the wet gauze using a rubber band.
Take the other thermometer and attach it to the other side of the bottle using tape. Make sure you can still see the numbers and the red alcohol in the thermometers.
Hold tightly to the end of the string and spin the bottle in a circle in an open-air space. Do this for 1 minute. Then, record the temperatures on both thermometers.
The wet bulb temperature will always be lower than the dry bulb because water evaporates from the wet bulb when you spin the 2 thermometers. The evaporation then cools the wet bulb. The drier the air is, the more water will evaporate from the wet bulb, leading to a higher temperature difference between the wet and dry bulb. For example, you spin the sling psychrometer outside and the dry thermometer has a temperature of 22 degrees Celsius. You get a wet bulb temperature reading of 12 degrees Celsius. If the weather is very humid one day, you may get a dry bulb temperature of 22 degrees Celsius and a wet bulb temperature of 21 degrees Celsius. Because there is very little water evaporation on the wet bulb, this indicates that there is high humidity outside.
The wind vane works by spinning and pointing in the direction from which the wind is blowing. This instrument has 2 parts or ends, 1 that is shaped like an arrow and turns into the wind and 1 wide end that catches the breeze. The arrowed end will indicate which direction the wind is blowing, for example, North, South, East, or West. You must be aware of where North, South, East, and West are relative to your location to use a wind vane properly.
A manila file folder A pin A pair of scissors Glue A pencil with an eraser A straw Modeling clay A paper plate
Take the straw and make 1 centimetre (0. 39 in) cuts on each end of the straw. Form the arrow by sliding the arrow point on 1 end of the straw and the arrow tail on the other end of the straw.
Push the sharp end of the pencil into a small lump of modeling clay to form the base of the wind vane.
Place the clay base, with the arrow attached, in the center of the paper plate.
You can also use a compass to determine the wind direction outside. Do this by placing the wind vane and the plate outside on a flat surface. Then, use the compass to determine where North is and set the plate so it faces the correct direction. Observe the wind vane. If it becomes very windy, hold down the paper plate so the vane does not blow away. Note the direction the arrow points to as the wind blows and check the direction on the paper plate to determine the wind direction outside. For example, if the arrow is pointing west, the wind is blowing from the west.
An empty, cylindrical jar that is clear, such as an olive jar A clear plastic ruler A rubber band A plastic funnel Clear tape
Another option is to tape the ruler inside the jar so it stands vertically, with the end at the bottom of the jar. Make sure you can read the numbers on the outside of the jar.
If it is going to be a rainy day, leave the rain gauge outside in a safe spot that is not covered by trees or other obstructions that can block the rain. Take a reading after each rainfall. Make sure you empty the rain gauge after every reading to ensure your measurements are accurate.
