© Sandrine New
To study the weather, meteorologists record and analyze data. It is possible to become an amateur meteorologist without spending a fortune on measuring instruments in constructing its own weather station and taking note of his actions.
This series of articles showing how to build some instruments for measuring weather station. While not extremely accurate, of course, these instruments may nevertheless be used to measure weather conditions and allow time to come.
Most instruments are simple enough to be built with children - sometimes with a little help - for a project to do at home or at school.
This article speaks of instruments used to measure humidity.
The humidity is measured in percentage. Air that has a 100% humidity is extremely wet.
The instruments used to measure the humidity must be placed outside in a sheltered location - such as in a weather tight box.
Hygrometers and psychrometers can
used to measure moisture in the air. Here's how to make them.
Model A: Make a Hygrometer
must:
- 2 nails
- 1 button
- a wooden plank
- an empty thread spool
- 2 sheets of paper
- cardboard thin
- 1
long hair - the glue
- 1 hammer
- scissors
Instructions:
1. A nail at the top of the board, in the middle.
2. Draw an arrow in the box and cut.
3. Draw a cloud and a sun on a sheet of paper and cut them out.
4. Draw a half circle using an entire sheet of paper, cut and paste on the board, towards the middle.
5. Wrap the hair around the coil in the opposite direction of clockwise. Hook one end of the hair to the nail at the top of the board.
6. Glue the middle of the arrow on one side of the coil. Planting the second nail in the center of the arrow and in the coil.
7. Planting this nail down the half-circle in the center. The arrow should be level.
8. Hang a button to the free end of the hair. Button hangs under the coil.
9. Paste the cloud to the left, and the sun right on the board.
Explanation:
When the humidity increases, the hair gets longer, rotating the spool counterclockwise in the world. The arrow turns left and points to the cloud. When the humidity of the air decreases, the shorter hair, turning the spool in the direction of clockwise. The arrow turns to the right and points to the sun.
Model B: Make a Hygrometer
must:
- a wooden board or a flat piece of polystyrene (about 22 cm x 10 cm)
- a flat piece of plastic (about 8 cm x 8 cm)
- 2
nails short - 3 long hair or human hair of horses (About 20 cm long)
- a coin
- glue
- tape
- a hammer
- scissors (strong enough to cut plastic)
Instructions:
1. Make it point by cutting the piece of plastic shaped like a triangle: take one side of the plastic as a base and draw two lines from the corners of the base, until the middle of opposite side. Cut along these lines.
2. Draw a line on the pointer that links the pointed end in the middle of the base.
3. Tape the piece on the pointer near the pointed end on the line.
4. One plant nails in the triangle near the base line. Enlarge the hole by grinding the nail. The pointer should move freely and loosely around the nail.
5. Glue the hair (or hair) to plastic, between the part and the nail hole on the line.
6. Draw a vertical line on the plate (or Styrofoam) in the middle along the length.
7. Place the cursor horizontally on the board about 3 / 4 distance from the top.
8. Drive a nail through the hole in the pointer, and the board. The hair must be pasted on the line of the board. The pointer should turn easily around the nail.
9. Planting another nail in the plate, about 2 cm from the top, also on the line.
10. Reaching the hair so that the pointer points to the horizontal - the line on the pointer must be horizontally. Doicent hair was perfectly vertical line along the base. Paste extémité hair to the nail on the board. Necessary, shortening the hair.
Explanation:
cells of human hair - and animals - indicate the amount of moisture in the air, stretching and contracting. When the air is moist, the hair stretches and the pointer point down. When the air is dry, the hair is shorter, and the pointer points above. Draw marks on the basis of the hygrometer to compare the different levels of moisture indicated by the pointer.
Model C: Building a Psychrometer
The humidity is measured sometimes with a psychrometer, which is an instrument consisting of two thermometers, one dry with a ball, the other with a wet ball.
must:
- 2 thermometers graduated about 0 ° C to 35 ° C
- cotton
- 2 elastic
- string
-
a small bowl - Water
Instructions:
1. Wrap the balls of the two thermometers the same amount of cotton held by a rubber band.
2. Tie a string to the other end of the two thermometers and hang out in the shade.
3. Place a bowl of water under one of the thermometers, so that his ball soaked in water.
4. Wait 30 minutes and compare the temperatures indicated by the two thermometers. Calculate the difference between the two temperatures and use the chart below to estimate the amount of moisture in the air.
The numbers in the middle indicates the humidity in%
Dry bulb temp difference between c thermometers
T ° c 1 c 2 c 3 c 4 c 5 c 6 ° c 7 ° c 8 ° c 9 ° c 10 ° c
(2 f) (4 ° f) (6 ° f) (8 ° f) (10 ° f) (12) (14) (16 ° f) (18) (20 ° f)
10-14 ° c 85 75 60 50 40 30 15 5 0 0
(50-58 ° F)
15-19 ° c 90 80 65 60 50 40 30 20 10 5
(59-67 ° F)
20-25 ° c 90 80 70 65 55 45 40 30 25 20
(68-77 ° F)
Sources:
http://www.fi.edu/weather/todo/todo.html
M ake Y o O wn W eather S tation
http://www. meteorologic.net / construct-sa-station meteo.php
http://ecolecentreferte.free.fr/projet-meteo/Le-projet-meteo.htm
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