Earth Science

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The weather has been in the news this weekend, so it might be a perfect time to build a weather station.

Background:

Because the weather changes from time to time and place to place, scientists use instruments to measure the weather conditions. They often group the instruments at one location, called a weather station. The scientists use the information they collect from many stations to make weather forecasts.

To make a weather station at home, consider the making or buying some of the following equipment:

  • Outdoor thermometer to measure temperature
  • Anemometer to measure wind speed
  • Wind or weather vane to record wind direction
  • Rain gauge to measure precipitation
  • Barometer to measure pressure
  • Hygrometer to measure amount of moisture in the air

Barometer

How to make an easy homemade barometer.

Thermometer

You may make a thermometer to see how one works, but you will probably need an outdoor thermometer to be able to take reliable readings outside.

Watch the video to see how to make a simple thermometer in this post about water and thermometers.

Water temperature science has more information about thermometers, too.

A Simple Weather Vane

Gather for each child:

  • A plastic drinking straw (body of vane) – straight, not the bendy kind
  • A pencil with a sturdy eraser (support the vane)
  • Index card, piece of file folder or heavy construction paper (for tail of vane)
  • Dressmakers pin
  • Scissors
  • Tape (optional)
  • Markers and/or crayons
  • Container about the size of a small flowerpot, or old flowerpot
  • Soil, pebbles or similar material to hold pencil upright in the container
  • Compass to find north, east, west and south, only one needed to share

Cut two slits across one end of the straw, about one inch long.

Make a decorative tail for the vane. Cut the index card or paper into a weather-related shape, such as a raindrop, a sun or a flat-bottomed cloud. Make it about two inches in length. Have the children color their decoration. Slip the midline of the tail into the slits in the straw. If it doesn’t fit tightly, add a bit of tape to keep it in place. If you plan to use it for an extended period outside, you might want to consider laminating the tail.

Fill the container at least part way with soil or pebbles. Place the pencil upright in the middle of the soil, with the eraser end up. Push into the soil until the pencil will stand up on it’s own, with the top eraser at least a few inches above the rim of the container. Add more soil as needed.

An adult will need to supervise this step for young children. Insert the dressmaker’s pin through the straw about two inches from the tail, in such a way that the fan is oriented up and down. The wind will be blowing from the side, so the tail should be positioned to catch the wind. Because the tail adds weight, the pin needs to be nearer the tail, rather than in the center, to balance. Once the pin is in place and oriented correctly, then push the pin into the top of the eraser. Blow on the weather vane to see if it can spin freely. If not, make the necessary corrections and try again.

To finish, take the weather vane outside where the wind might blow. Use the compass to determine the directions. Mark the container with north, south, east and west. Once the pot/container is marked, leave it in place. If it gets moved, be sure to correct the position with the compass. Record the wind direction as it changes over time.

Anemometer

You can easily modify the weather vane into an anemometer, which is a device to measure wind speed rather than direction. Or make another using the directions above.

Gather:

  • Weather vane and materials above
  • Large needle or sharp nail
  • Two pieces of cardboard about 1½ inches wide by about 18 inches long
  • Foil muffin tin liner cups, or bathroom-sized paper cups
  • Staples or tacks
  • Watch or timepiece with minute hand

Remove the pin/straw from the eraser, but leave the rest of the weather vane intact. Cross the two pieces of cardboard and mark the center. Cut a slit half way through the middle of each, turn one over and then slide the two pieces together. They should overlap and form an X-shape.

If you are using paper cups, cut the rims off to reduce the weight. Staple or tack the muffin cups or small paper cups to the ends of each strip of cardboard, so they are all facing the same direction, for example in a clockwise direction. These are the cups that will catch the wind and be pushed around. Chose one arm and color the cardboard with a marker. This will help you count how fast the anemometer is revolving.

An adult will need to help with this step. Take the needle or sharp nail and drive it through the center of the cardboard X in such a way that the cups will rotate around from side to side. Once the needle through, push the point into the pencil eraser as before. Blow on the muffin cups and see if they will spin. Adjust accordingly. You may have to replace the needle if it is too short, or trim up the cardboard arms. Add staples if it is out of balance. Make the hole in the center larger, if it is too tight.

Take the anemometer outside. Place on a table or other structure, so it isn’t on the ground. Count how many times the colored arm passes per minute as a measure of wind speed.

Rain Gauge

The Miami Museum of Science has easy steps for how to make a rain gauge, complete with a rain gauge ruler to print out.

Take your equipment outside at least once a day. Record the results. Check with local forecasts to see if your results match theirs. Note:  Often the official weather station is in a shed or box to prevent the equipment from being exposed to direct sunlight. How might that make their results differ from yours?

(Note: this activity has been posted on the Growing With Science website, but since I am making some modifications to the website soon, I decided to revise it and post here).

Looking for children's books? Try our growing list of weather books at Science Books for Kids.

Weather-books-for-kids

This week let's take a look at a weather phenomena that has been in the news in the Southwest:  dust storms.

On July 5, 2011 a huge dust storm hit Phoenix. It was a wall of rapidly blowing dust 5,000 feet high in some places.

This time-lapse video shows how it looked as the curtain of dust approached.

(In inside look at how the video was made.)

Dust storms occur most frequently in arid regions, such as the southwestern United States, the dry areas of Australia, the Middle East (see a similar dust storm that happened in April in Kuwait), China and the Sahara Desert. Here in Arizona we have them most frequently in the summer, typically in late June and July, although sometimes into September if the summer rains fail to materialize.

Why summer? The dust storms are fueled by the intense heat that causes air to rise, just like happens with thunderstorms. The rising updrafts eventually begin to cool when the air gets high enough and a rush of air starts down. Under certain conditions, the thunderstorms collapse and the down rushing air can be intense. Huge gusts of wind pick up any loose soil particles as they flow by. Where there are large areas of exposed soil -such as in deserts- the amounts of dust picked up can be extremely high.

Plants the day after the dust storm in Phoenix

To give you an idea what dust in the air was like during the recent storm, let's take a look at the records from the weather stations that record the amount of particulates in the air. On a normal day, the average amount of particulates is 38 micrograms per cubic meter of air. On July 5th the readings ranged from 2,576 to 5,190 micrograms of particulate per cubic meter. (Source:  The Arizona Republic, July 24, 2011). That's a lot of dust!

For some related hands-on activities, try the Wind Power post.

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We have a lot of intriguing things to see in Arizona, especially for families interested in rocks, geology and earth science.

The Petrified Forest National Park is an excellent example. It is found in the northeastern area of the state.

The visitor is greeted by great logs that look like they have been carved from stone.

The different pieces come in a rainbow of colors.

You soon learn that petrified wood forms under special circumstances that allows minerals to seep into the cells of the wood and harden. Iron oxide makes the petrified wood look red or orange (rusty), whereas manganese oxide produces blues, purples or black. Other compounds may cause the petrified wood to be greenish or yellow.

Activities:

If you have a piece of petrified wood (often available at rock shops), look at it with a hand lens. See if you can identify the tree rings, or other structures that were parts of the original tree. A few of the logs we saw had remnants of bark.

Sometimes you can identify the  type of tree the wood came from. For example, the Texas State Stone is petrified palmwood, coming from a petrified palm tree. (Technically a fossil, petrified wood is also Arizona's state fossil.)

For more information and activities, try:

Rockin’ Through the Ages: From Fossils to Petroglyphs Curriculum at the Petrified National Park website (free .pdf files) Examples include making a personal timeline. Fun!

Make a permineralization fossil using wax and a sponge (from Bryce Canyon National Park)

Petrification cycle activity (activity is towards the bottom)

Loose in the Lab post about petrified wood

Your Gemologist has a child-friendly discussion of how petrified wood forms

Have you ever been to the Painted Desert?