Jewels of the Forest

What's the big deal about the native Hawaiian tree snails?

Image from Hawaii Forest and Trail

• These snails are not very ambulatory. Some are thought to stay in the same tree (usually Ohia or Kopiko trees) their whole life. Because of this, it was easy for populations to become isolated and change. Because the snails are isolated on island ridges and in lush valleys, they changed and developed into a different species. Each species has its own spiral coloration diverse in patterns, colors, and shapes. The shells are glossy and oblong. Because of the shells' beautiful coloration, the snails are known as jewels of the forests.
• Tree snails give birth to only one or two babies a year.


• Today, many of the species are extinct, and the remaining populations of Hawaiian tree snails have been classified as endangered. On the island of Oahu, all species of the genus Achatinella, also known as the O`ahu tree snails, are federally listed as endangered.


• The snails don't eat their native host plant. The snails are fungus eaters and are especially fond of black sooty mold. By gleaning the leaves of mold they assist in photosynthesis and keep the plants healthy.

Threats to the species...

• The achatinella and other various species were so beautiful and plentiful that local residents collected them by the thousands in the 1800's.


• Predation has also played a significant role. Once rats made it to the islands, they found the snails to be quite delicious. Even more insidious than rats was the deliberate introduction of the carnivorous snail Euglandia to the islands. Originally brought to the islands and released in 1955 to control the alien African snail, which is an agricultural pest and an intermediate host for cattle liver fluke, it soon found the Hawaiian snails easy prey. In a few years the euglandia made its way from the lowlands up into the native forests and remaining pockets of native snails disappeared. Increased urban construction has crowded out native snails.

Image from www.hawaii.gov/dlnr/Aliens2.html

Image of euglenia snail from www.naturesrepellent.com/images/rosy.jpg

Resource Links

Hawaii forest and trail

U.S. Fish and Wildlife Service

Solar Energy

When I was a sixth grader at E.B. deSilva Elementary, I had a fun teacher who embraced science. My teacher enabled me to explore the earth's processes and elements with fun activities and experiments. One of the lessons focused on solar energy. One of the science activities I performed was the building of solar ovens. I remember building the solar oven that used the sun's energy to cook pizza bagels, but I don't remember much about what solar energy is, how solar energy is used, and how a homemade solar oven works. This leads me to further wonder and investigate...

What is solar energy?
Solar energy just means energy (light or heat) that comes from the sun. For example, plants use solar energy (light) to grow. Solar energy heats the inside of our cars during a hot and sunny day.

How can we use solar energy?
There are two basic ways that we can use solar energy. We can use the sun's energy to heat things--our houses, the water in our houses, the food in a solar cooker, and so on. This is called solar thermal energy. (Thermal means heat, so solar thermal energy just means heat energy from the sun.) The second basic way we can use solar energy is to turn light from the sun directly into electricity, using solar panels.


Solar electric panels are made up of something called silicon, the same thing that makes up sand. There is more silicon on the planet than almost anything else. Even though you can find silicon almost everywhere, making a solar panel is difficult and expensive. The silicon has to be heated to super high temperatures in a big factory, and then formed into very thin wafers. When sunlight hits a solar panel, it makes electrons in the silicon move around. (Electrons are teeny tiny specks--they're way too small for us to see, even under a microscope.) The electrons flow through wires that were built into the solar panel. And presto! We have electricity! We can do whatever we want with this electricity, run a calculator, a CD player, or, if we have big enough solar panels, a satellite! [Solar panels are also called photovoltaic panels. "Photo" means light and "voltaic" means electricity.]
When the sun stops shining on your solar panel, its electrons stop moving and electricity stops flowing. So what do you do if you want to be able to read or watch television at night? (But you don't watch television, do you?!) What stores the electricity in a flashlight? Right! A battery! And that's exactly what people do with solar panels... they attach batteries. The batteries are big, heavy, rectangular boxes, sort of like car batteries. Electricity from a solar panel flows into attached batteries while the sun shines, and then the stored electricity in the batteries can be used at night, or when the sun is behind the clouds.

You have probably seen big panels on the roofs of houses. These panels are used to power the house with electricity provided by the sun!!!

To read more about solar panels and solar energy, look at this excellent site on solar energy


How does a solar oven work?
We can use solar energy, or the heat from the sun, to cook our food in a solar oven. A solar oven is an insulated box with a transparent top and a reflective lid. The box usually has one or more reflectors with aluminum foil or other reflective material to bounce extra light into the interior of the box. The inside bottom of the cooker should be dark-colored or black. The inside walls should be reflective to reduce radiative heat loss and bounce the light towards the dark bottom. We can make our own solar ovens from our own pizza boxes or shoe boxes. Solar ovens are great because they save energy and minimize pollution. It is a lot of fun to cook and then eat your own pizza in your own homemade solar oven.


Make Your Own Solar Oven
What you need:
shoe box or pizza box (ask a pizza restaurant to give you one, a square box is best)
ruler
marker or pen
scissors
plastic wrap
aluminum foil
tape or glue (it should say 'non-toxic')
drinking straw or stick
black paper (newspaper may also be used as an alternative)
a sunny day
pizza bagels, hot dogs, or marshmallows with graham crackers (for s'mores)

1. Draw a square on top of the pizza box. Make it one inch away from the edges. Have an adult cut along three sides. Do not cut the line along the back of the box.


2. Make a flap by folding back along the uncut line.3. Cut a piece of foil to fit the inside of the flap. Glue or tape the foil in place, shiny side out. If you put it on carefully, it will not wrinkle much. Press out any wrinkles with your fingers. 4.Cut the plastic to fit over the hole that the flap made. Make sure the plastic is much bigger than the hole. Tape the plastic to the box. Seal the plastic tightly so that the air cannot get out.5. Cut another piece of foil to cover the bottom and sides of the box. Glue or tape the foil into place. 6.Cover the foil with black construction paper, and tape it into place. 7. This is what your finished solar oven will look like...8.To cook something... lay a piece of foil in the center of the box. You can also use a napkin or paper plate. Put the hot dogs, pizza bagels, marshmallows/crackers, etc... on the foil. 9. Close the box. Open the flap of the box. Prop the flap open with the drinking straw or stick. Turn the flap towards the sun. You want the sun to reflect off of the foil and into the box. It may take about an hour to cook a hot dog; solar ovens are slow cookers.
Take a look here for more information on how to make solar ovens, and here for more information on solar cooking.

The Sky

When the sun shines brightly and a few clouds scatter the sky, the sky is blue. We see the sky everyday, and yet the sky is always blue. Except during cloud coverage and sunsets, the sky never eludes its blue color. Because I see the blue sky everyday, I have always wondered why the sky is blue and not green or purple.

Here is a science made simple link about why the sky is blue

The sky is blue because of the light that enters our eyes.
Before we answer the question, "Why is the sky blue?" we must first know what light is.
The reason we all are able to see with our eyes is that light enters our eyes. Light exhibits the characteristics of a wave. Light's waves may be visualized as a curvey line.

Waves display a pattern of alternating crests (the top curve of a wave) and troughs (the bottom curve of a wave). The distance from one crest to another is the wavelength.





A wave, wavelength (distance between crests), frequency





A wave, crest (the top), and trough (the bottom)

All waves have a frequency. The frequency of a wave is the number of waves that are made per second.



Take a look at this link to see an animation of wave frequency



As the frequency of a wave increases, the wave length decreases. As the frequency of a wave decreases, the wave length increases. The frequency of a wave of light determines the light's color. When sunlight is separated, the light is separated into many different colors. Sunlight may be separated through a crystal prism, glass, or rain drops. Rainbows are created by the seperation of the sun's light through rain drops.

sunlight may be separated into colors by raindrops...rainbows!

The earth's atmosphere also has a role in separating the sun's light. The atmosphere is composed of oxygen and nitrogen gasses. Blue light has a high frequency and a short wave length. The wave length of blue light is about the size of an oxygen atom. Because of the wave length the size of an oxygen atom, blue light interacts with the oxygen in the atmosphere. The light is scattered by this reaction. Because the scattered blue light enters our eyes from many different angles, we all see the entire sky in the color blue.