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Weekend Science Fun: Wind Power

August 22, 2009 / Roberta / 0 Comments

Wind, or the movement of air, can be a powerful thing. People have used the wind to do work for hundreds of years. From sailing ships to modern wind turbines, the wind has been harnessed for many useful purposes.

This week we have been investigating how air movement works with various pinwheels, windmills and propellers.

Activities:

Blowing Feathers/Streamers

You can learn about wind using a household electric fan. Be sure to remind your children about safety around fans, such as never sticking anything into the moving blades.

Gather:

Feathers or other lights objects, such as bits of tissue (available in craft stores)
Electric household Fan

Give each child a feather or piece of tissue and allow them to blow on it. Let them free explore, seeing how the feathers lift and fly as the air moves. When they are finished, turn on a fan. Allow them to drop their feather in front of the fan. Does the feather move differently? An actively working air return vent can also work if you don’t have a fan. Repeat using tissue streamers, if available.

If possible, let the children try this outside when there is a breeze.

Windsocks/Streamers/Wind Chimes

Make or obtain a windsock

How to make windsock video

Hang the windsock (or wind chimes) outside. Watch them often. Discuss whether the day is windy or calm. Explain that windsocks are found at airports, The pilots need to determine the direction and strength of the wind when they take off and land the planes.

Pinwheels

There are hundreds of ways to make pinwheels on the Internet. Here is one way to make a simple pinwheel.

Gather:

Heavy paper, card stock or file folder
Pencil with eraser
Dressmaker’s Pin
Drawing compass or circular pattern
Ruler
Scissors
Modeling clay

Draw a circle about three inches in diameter and cut it out of the paper. Find the center of the circle. Draw a line through the center across the circle. The draw another line perpendicular through the center, creating four equal wedge or pie shapes. Now draw two more lines across the center dividing the fourths in half. You will have eight wedge shapes. Cut along each of these lines to about 1/4 inch from the center.

Have and adult place the pin through the center of the pinwheel and push into the side of the pencil eraser. The pencil will be the handle. Be careful with the pin around small children. Place the modeling clay over the sharp end of the pin to hold it in place. Now gently bend one corner down on each wedge, making sure to create the same angle with each.

Blow on your pinwheel or push it through the air holding the pencil. It should spin as the air hits it. Putting it in from of a fan is fun too.

Here’s another version:

Windmills

Windmills are basically pinwheels that do work of some kind. In the past windmills were used to grind grains, make paper, extract oils from seeds, and pump water, among other things. These days people are investigating many ways to generate electricity using wind.

W.carter, CC0, via Wikimedia Commons

Bug of the Week: Ant Lions

August 19, 2009 / Roberta / 2 Comments

Are you ready to find out what the mystery insect was in last week’s post?

ant lion pit

Most of you probably noticed the two circular depressions. The creature at the bottom of those funnel-shaped pits is the larval stage of the ant lion, also called a doodlebug. Ant lions are found in warm areas throughout the world, including Florida and the southwestern United States.

If you were to dig out the bottom of the pit, you would find the ant lion larva, which looks a bit like a lacewing larva and the two are related. Here’s a photo of an ant lion larva from Iowa State University. Some species have even longer jaws.

The ant lion larva digs a pit in loose dirt or sand near ant colonies. They spiral around and around from the surface down to the lowest point, creating a steep and slippery slope. The ant lion prefers to dig in areas with fine sand, and maintains the pit by throwing out any pebbles or bits of plant that might fall in.

When an ant or other small insect falls into the pit, the larva flicks sand at it to knock it towards the bottom. Once the ant is within reach, the larva grabs it and drags it under the sand and eats it. Donâ€™t feel too bad though, many times the ant is able to scramble out of the pit unharmed and the ant lion often goes hungry.

When the larva attains its full size, it pupates. The pupa is round and covered with a layer of silk and sand, similar to that of the lacewing. The adult ant lion emerges from the sand. It is slender with wings with many veins that fold back over its body when it is at rest. The adult might be mistaken for a damselfly or dragonfly. Firefly Forest has a fantastic photograph of an adult ant lion, go on over and take a look.

Have you ever seen an ant lion?

For more information:

Sea Horses and Other Fish

August 16, 2009 / Roberta / 1 Comment

Our family finally made it to the beach and had a lot of fun. We visited the Monterey Bay Aquarium and saw the “Secret Life of Sea Horses” exhibit. It was awesome, take a peek (the aquarium was packed, so excuse the noise):

What kind of creatures are sea horses? Are they fish? They have an exterior that looks rather hard, so some people might wonder if they are crustaceans. The tiny fins and gills give it away though, sea horses are fish! If you replay the video, look for the tiny gills and fins moving.

Sea horses and their relatives, the pipefish and seadragons, are called gasterosteiform fish because they lack scales and have bony plates instead. They are poor swimmers and often rely on camouflage to hide from predators. The seadragons in particular have so many leafy flaps on their bodies they look like floating seaweed instead of animals.

Sea horses are carnivores and eat small crustaceans, such as tiny shrimp and planktonic invertebrates.

This pretty silly video from National geographic gives more fun facts.

Activities:

1. Gyotaku and fish anatomy

Are you familiar with the Japanese art of gyotaku, making prints or rubbings from fish?

gyotaku

Traditionally, prints were made by applying paint to actual fish. Today you can buy rubber or plastic replicas, including those for sea horses. You can print on paper or cloth as you choose. This particular fish is printed on cloth.

Our instructions for making gyotaku (previous post).

2. Moving Through the Water.

Different fish have different shaped bodies. Do some move through the water more easily than others?

Check the CDAS website or the Catalina Island Marine institute for an introduction to fish body types.

Gather:

modeling clay
string or yarn
scissors
sink with water

Cut a few pieces of string about 18 inches long (at least two). Form a few golf ball-sized lumps, the same number as pieces of string. Take a small lump of clay and wrap around one end of the string, so the string is embedded. Form the lump into a rough sea horse shape (perpendicular to string).

Now take another ball of clay and wrap around another piece of string. Form this into a typical fish “tube” shape wrapping around the string.

This shape is called fusiform.

Put each shape into the sink and drag across the water. Does one shape move more easily than others?

Try some other fish shapes as well. Which shape moves through the water most easily?

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Now it is time to finish our summer beach science series and get ready for fall. We’ll miss the sand between our toes (although I think I still have some in my hair), but look forward to a brisk change of pace and some autumn foliage.

ocean