# Archive for October, 2010

## Water Displacement

Objective: Students will use critical thinking skills to formulate a hypothesis.
Resources:
Teacher: A deep bowl or wide-mouth jar, water, a wooden block, balance scale, masking tape.
For each group: A deep bowl or wide-mouth jar, water, orange.

1. Procedure: Divide the class into teams.
2. Hand out materials.
3. Demonstrate for the class that floating objects displace (push out) as much water as they weigh.
-Fill a large container with water halfway.
-Mark level of water with masking tape.
-Place wooden block in the water.
-Remove water from container and place in balance pan. Continue this until level of water is back to level mark.
-Remove block from water and place in balance pan opposite water.
-Water and black should balance.
4. Discuss the results.
5. Instruct students to place oranges in their containers that are filled halfway with water.
6. Have students remove peeling of orange and try floating it.
7. Have each team take the orange apart and try floating each section.
8. Teams should discuss and write about results.

## Cause & Effect With Eggs

Overview: To show examples of cause and effect and encourage students to recognize the process around them.
Resources: Teacher: one hardboiled egg; one raw egg; one bowl. Student: pencil, paper.
Teacher Preparation: boil one egg before class and mark it.
Procedure:

1. Hold up raw egg and say “CAUSE” as you crack the egg on the side of the bowl.
2. Say “EFFECT” as you break open the egg into the bowl.
3. Hold up the hardboiled egg and say “CAUSE” as you go through exaggerated motions of tossing the egg to a student.
4. As they either catch it or drop it, say “EFFECT”.
5. If student catches the egg, retrieve it, then go through the cause-and-effect procedure again, but this time, just hold it up and drop it on the floor.
6. Have students locate all the possible causes-and-effects that have taken place (e.g. boiling the egg makes it hardboiled.)
7. Have students write down real-world examples of cause-and-effect.

Variations/Options: Look for examples in different subject areas: driving on slick streets and slamming on the brakes, not getting a term paper done on time, taking your parents’ car without permission, adding two whole numbers together, staying up until 3 a.m. watching movies the night before school, being late to a job repeatedly, leaving clothes next to a room heater or hot water heater, seeking retaliation against an enemy during war. Also, have them give examples from their own lives.
(Note: putting an egg on a flat tabletop and spinning it is a way to tell if an egg is raw or hardboiled. A hardboiled egg spins freely as you would expect, but a raw egg slows down quickly and behaves sluggishly, due to the motion of the liquid inside.)

## Field Trips and Simple Physics

You can turn a bus ride into a physics experiment that will even have your fellow teachers scratching their heads. Everyone knows that a weight suspended by a string and taped to the ceiling of the bus will appear to swing backward as the bus speeds up, and forward as it decelerates, due to inertia. Also take along a helium-filled balloon on a string to tie to a seat or fasten to the floor. What will it do? The opposite. You’ll have a great time getting students to hypothesize then try to explain the result.

We know that air has mass so it also has a certain inertia; when the bus moves forward the weight hanging on the string AND the air in the bus both tend to stay where they are, thus appearing to move backward. The air molecules tend to compress together toward the back of the bus, changing the air pressure in much the same way as barometric pressure changes. Tighter molecules, more pressure. The balloon, meanwhile, is trying its best to move to an area equal in density to its helium (somewhere out in the upper atmosphere, actually) so as the air pressure in the bus increases, it tends to move to an area of lesser pressure. What we really have is a bus full of air sloshing around inside, changing pressure as the bus accelerates, decelerates, or turns, with a balloon trying to get to the area of lowest pressure.

(I should mention here that we have to assume the windows to the bus are closed, otherwise the pressure changes wouldn’t take place.) I also will mention that when I first heard of this, I didn’t believe it until I consulted someone who knows much more about these things than I. Now when I drive down the street behind a vehicle carrying one of those “balloon bouquets” I pay attention to what happens to the balloon inside as they change speed or turn. Sure enough, they defy common sense, and adhere to the laws of physics instead.

Happy experimenting,
Lee Shiney, Teachnet editor

## Magneto-hydrodynamic Drives

By T2T Contributor, David Richards

Objective:
The objective of this lesson and demonstration is to get the students to see how electric and magnetic fields can be used to force water out of a chamber in order to propel a vehicle such as a submarine.

Resources:
Small tray 12in x 5in x 2in
two conducting bars (i.e. aluminum)
a DC power supply (capable of 2A)
a strong horseshoe magnet
water
salt
pepper

Teacher Preparation:
Need to understand the basic principles behind crossed eclectric and magnetic fields

Procedure:
Take the two conducting bars and place them in the tray. Hook the leads from the power supply to the conducting bars. Pour water into the tray until it is about 1 inch deep. Place horseshoe magnet so that the poles are between the two conducting rods (above and below the tray). Poor salt into tray and stir. Next, poor some pepper in. Now turn on the power supply and crank up the voltage until you get a current to flow between the two conducting rods You will see the pepper begin to circulate around the conducting rods.

Variations/Options:
This principle is used in submarines like the one in “The Hunt for Red October”. It is a propulsion drive that has no moving mechanical parts, therefore it is difficult to detect through sonar. The students can come up with other examples of this phenomenon.

Real World Usage:
Students should think about how this phenomenon can be modified for different uses.

Check out the book “The Hunt for Red October”

## Day and Night in the Desert

Overview: Draw contrasting scenes representing daytime and nighttime activities in the desert. Requires previous discussions of plant and animal life
Procedure Ideas:

1. Students tape four sheets of construction paper together into a two-by-two grid, with white or light blue on the upper left (day), black or dark blue on the upper right (night), and light brown on both bottom sections (underground).
2. Label the sections “day”, “night”, “underground”, etc. Students can also include information in small boxes such as normal daytime and nighttime temperatures, and rainfall.
3. Draw on white paper with markers or crayons, cut out and paste down plants and animals on both halves, showing what they do both during the day and the night. When and where do they sleep? When do they eat?
4. Lines can link predators and prey, and relationships between plants and animals.
5. Finished scenes can be used for display in the halls.
6. An alternative is to make one large diorama at the beginning of the desert unit. Tape a 10 cm cardboard “wall” to the edge of an empty table, and put in sand to cover. Assign individual students to use modeling clay or draw on cardboard the plants and animals as they are covered in the unit, and stick them in the sand. Over the course of the unit your 3-D desert will “come to life”. Plants and animals can be labeled with information about how they contribute to the desert ecosystem, and when they sleep and eat and if they spend part of their time underground.

## Creating Water in the Desert

Overview: This is such a neat little experiment, it’s fun and informative for all ages. Based on the process of condensation, it appears to create water from nothing (which is, of course, not the case).
Teacher Preparation: Aquarium, sand, clear plastic, small container like a jar lid, plant, water.
Procedure Ideas:

1. Put 5-10 cm of sand in aquarium.
2. Hollow out a 10-15 cm depression in the sand.
3. Place jar lid in the center of the hole, and plant material (small whole plants or broken up larger ones) around the container on the sand.
4. Lay 20×20 cm clear plastic over the hole, and hold in place with sand or pebbles around the edges.
5. Put just enough sand or a pebble in the very center of the plastic to make it sag slightly. Too much weight will pull the plastic loose around the edges.
6. To speed up the process, place a light bulb over the aquarium to warm the sand and plastic, as the sun might.
7. Water from the plants will form on the underside of the plastic by evaporation (from the plants and residual moisture in the sand) and condensation. If the plastic sags enough, the moisture will run to the center of the plastic and drip into the container in the bottom of the hole.

## Understanding Time Zones

Understanding Time Zones:

Overview: It used to be that knowing the time zones for your country was enough. But now, with the Internet and e-mail, we find ourselves wondering what time it is in Australia and other parts of the world.
Teacher Preparation: Look up links to other websites. Cut a large sun out of yellow paper.

Procedure Ideas:

* For younger students: create a room sized map by assigning each student a state name to write on a sheet of paper then have them go stand in the proper location for that state. They may need to consult a map or globe first. Divide them by timezones with strips of crepe paper or yarn. Then move the paper sun from one end of the room to the other to simulate the movement of the sun across the country. As you move, have them figure out the time for where they are standing.
* Draw a 1 foot circle divided into 24 sections to make a graphic to place under a globe. Each section represents an hour of the day and rotating the globe shows the time for any given part of the world.
* Older students can benefit from the following Web links, and from discussions of the International Date Line and Greenwich Mean Time.
* The Directorate of Time, U.S. Naval Observatory
* World Map with time zones
* Discuss situations where knowing time zones is important: placing phone calls to other parts of the country, IRC chats with people in other parts of the world.

## “Farlandia” – A Ficticious Ecosystem

Multi-media Interactive Web Site Lesson Plan for Science
Topic: Ecology
Software used: MS Publisher 2000, Web Wizard

T2T CONTRIBUTOR: Submitted by Dr. Pelham Mead ED.D., Past Technology Coordinator and now Adjunct Professor at Pace University, Pleasantville, NY in Web Development and the Internet.

Last year I was a technology coordinator at a K-8 school in Emerson, New Jersey, and this is one of the lesson plans I developed with the 5th grade science teacher. The topic was Ecology and each student was to research an assigned ecological environment. Students were broken up into pairs and began to research the following eco-systems:

*Rain forest ecosystem
*Desert ecosystem
*High country mountain ecosystem
*Grassland plains ecosystem
*Marsh wetlands ecosystem
*Pine Bog ecosystem

I helped several students draw a map of an imaginary country using MS Paintshop. We saved the picture as a .gif image and then put little icons (pictures) of typical plants or animals and include text to describe the eco-systems.
We then added one page for each of the ecosystems and saved the whole file as a Web site. I showed the students how to link the ecosystems labels on the map to each of the corresponding ecosystem information pages. We saved that work and also added sound wav files to each page that seem appropriate to the ecosystem in jungle sounds for the wet forests, frog sounds for the marsh
ecosystems, etc..

The major part of the project was for each of the student groups to research and type up one page in MS Publisher and save it with clip-art included. Each of the pages were copied onto the blank pages already created in the web site and re-saved as a web site when all was done.

We published the 9 page web site to a free ISP (Geocities) and also published it to a file on the school LAN system for an Intranet web site as well as an Internet Web Site. The Unit concluded with a demonstration in class by each of the student teams showing how the map linked to their informational page.

We called the imaginary country “Farlandia.” It was a fun experience for all involved and the parents of these fifth graders were able to view their work on the internet. The whole unit took about six classes spread out over one month.

## Pond Water Comes to Life Before Your Students’ Eyes

Back in October we brought in several water plants from our outdoor pond to winter over indoors and floated them in a couple gallons of water. We recently took a look inside to see what kind of gunk was rotting away, but instead of finding a smelly mess, the water was clean, and full of living things. Snails were cleaning house, and small crustaceans of various types and sizes were swimming everywhere. Try a gallon jar of pond water with a plant or two in your own room, and see what develops over the next few months.

## Identifying Parts of a Flower

Objective: The student will be able to identify, dissect, display and label parts of a flower.
Resources: Teacher: flowers (lilies are especially easy to distinguish stamen and pistils), tweezers, white paper, clear tape. Students: pencil.
Teacher Preparation: This lesson assumes a prerequisite lesson on parts of the flower. Flower blooms will be needed (see tip above).

1. Procedure: Each student or pair of students should be given a flower bloom, tweezers, white sheet of paper and clear tape.
2. Have the students locate the stamen, pistil and petals of the flower.
3. With tweezers or fingers, students should remove the three flower parts.
4. The students should tape these to a white sheet of paper and label each part.
5. If enough flowers are available, the students may also tape on the paper a complete flower for comparison.

Variations/Options: Accompanying paragraphs to describe the parts labeled; use multiple flowers per group to show differences between different blossoms.

## Going to Seed

Quick, summer is over and fall is threatening with freezing temperatures. Take the last few days of nice weather and collect some seeds to use in winter projects.

Fall is the time when many plants are losing their seeds and beginning to die off for winter. Round up some of these dried up flowers so your students can examine the seeds left behind, then plant some in soil so they can see them sprout. With luck they may grow through the winter, not only adding a little green life to your room, but also illustrating the plant cycle.

Gently place a small bag over the dead flower head. Using a pair of scissors, snip the entire head off into the bag. Repeat to collect several heads. When you’re ready to use the seeds, close the bag and shake to loosen the seeds from the flower heads. Some seeds will release easier than others.

## Reindeer Research

Objective: Students will use research and writing skills.
Resources: Teacher: none. Student: pencil, paper.
Teacher Preparation: none.

1. Procedure: Ask students for information on what they know about reindeer.
2. Go to library/internet to research reindeer, looking for information on where they live, what purpose they serve to humans, what the history is regarding their Christmas significance.
3. Students write a short fiction story about a reindeer, using information from their research.

Variations/Options: Research to see if any other instances occur in history of Rudolph the Red-Nosed Reindeer; have students brainstorm ideas to really make reindeer fly (wings, jet packs, etc.) then draw their inventions; estimate how many total gifts might be needed for your town or city, then estimate how many reindeer might be needed to pull the sleigh.

## Plant Growing Projects: Seed Planting Tips

If you are going to grow seeds, put them in water on Friday to soak so they will be ready for students to prepare on Monday for growing. They will sprout early in the week, giving students more time to view the growing stage uninterrupted. Radishes and alfalfa sprout faster than beans, and if it’s out of season to buy garden seeds, a health food store that sells seeds and grains for sprouting and milling may carry radish, alfalfa, mung beans, wheat and corn year ’round.

## Hunter-Gatherers in the Classroom

We are finally experiencing cooler weather after a long, hot summer. Flowers have, in most cases, gone through their useful life. Those dried-up flowers don’t indicate a dead plant, of course, but the beginning of life. Now is the time to bring in seeds to examine and save over for next spring. Here are some ideas:

Seed Center
Have students draw pictures of plants, research the proper names and attach samples of seeds. How fast did the plants grow? What are the plants’ dimensions? What are the root structures? Do they like shade or sun? What kind of conditions will likely cause the seeds to sprout?

Seed Comparison
A quick walk through a garden will reveal different ways seeds form and are scattered. For example, you will find seeds in berries and fruits, those formed in the centers of flowers like sunflowers and some in seed pods that form after flowers have died off. Look at how the seeds are scattered…do they fall direct to the ground or do they have ways to make them mobile?

Winter Over
Save seeds for planting next spring. Remember that some seeds need to freeze over the winter in order to germinate properly in the spring. What happens if seeds are planted now? Can they be frozen in a freezer for a few weeks, then forced to grow in the classroom? If so, will they grow all winter? What conditions: light, moisture, head, type of soil, etc. must be met for seeds to sprout?

Seed Math
Estimate how many seeds are produced by an average plant. If they all grew, how many plants or how much area would be covered by plants in five years?

Seed Stories
Write stories about seeds, from the seed’s perspective. In a paragraph or two, cover the entire life process of the seed.

Extra Credit
Have students do some brief research on “seed savers.” Many gardeners save and share seeds in an effort to revive certain types of “vintage” plants. As the years go by and commercial seeds proliferate, many of the original plant types get lost. Have students write about the virtues of saving seeds and what it means for future generations of gardeners or farmers.
The Seed Savers Exchange has a beautiful and informative website. They also offer school fundraising programs!

## Terrariums: The Water Cycle

Terrariums are wonderful projects: they’re easy to plant, easy to care for and they look wonderful. They also recycle their moisture, so they rarely need to be watered, requiring almost no attention. Often, a closed terrarium can be left for a month or more between watering.

Discussing the water cycle is a great introduction for this project. What are clouds? What are they made of? What is rain? What does the sky look like when it rains? Why does it rain? Where does the rain go after it falls? What happens to puddles after it rains? These questions will start a discussion about evaporation, condensation, and precipitation. Discuss each of these things as you put your terrarium together. (You may want to check out the animated diagram of the water cycle from the US Environmental Protection Agency.)

Any clear container can be made into a terrarium; just make sure that your container is watertight. Choose something large enough to accommodate the plants, and has a cover, lid, or door to keep the moisture from escaping. Jars, bottles, and aquariums are commonly used and each works great. Whatever the container, you can now easily bring nature into the classroom.

Many plants do well in terrariums, and it is best to choose the ones that will fit the size of the container. Slower growing plants require less trimming, and are less likely to take over. If you are willing to pay more attention to them, you can experiment with more aggressive plants. They require more frequent trimming, but will allow you to have more variety in your terrarium.

Some plants suitable for terrariums are:
Pilea (Aluminum Plant )
Fittonia ( Nerve Plant )
Ardisia
Podocarpus ( Buddhist Pine )
Aeschynanthus ( Lipstick Plant )
Baby Tears ( Very aggressive grower! )
Very small ferns
Miniature African Violets
Coffee Plant
Creeping Charlie
Boxus (Boxwood)
Wandering Jew (Aggressive Grower)
Creeping Fig (Aggressive Grower)
Moss

Planting Instructions:

1. Place a 1/2 inch layer of small gravel in bottom.
2. You may choose to sprinkle activated charcoal on top of the gravel, but this is optional. It will help to filter the water as it drains through the layers.
3. Test your potting soil before using it by squeezing a handful. If it clumps easily, add some Perlite or Vermiculite to help with drainage. These can usually be found in garden shops. Add a 2-inch layer of potting soil, or possibly a little more depending on the size of your container and the size of the plants you intend to use.
4. Add your plants, again taking into account the size of the space you have to work with inside the terrarium. Be careful not to overplant – you need to leave plenty of room for your plants to grow. Push the soil aside, place a plant in the depression, and gently replace the soil around the roots of each plant. Water lightly.

Care:
Neglect It! Water lightly only when the soil is dry. You should only need to water, at the most, every couple of weeks, depending on conditions. Be very careful not to overwater! Place in a bright area, but not in direct sunlight. You should have enough light to read by. When plant gets as big as you want, pinch off the newest growth to encourage bushier growth.

Do not fertilize. As the nutrients found in the potting soil get used up, the plant’s growth will slow, helping to keep the plant from overgrowing the terrarium. Over time the soil can be “refreshed” by scraping off the top layer of soil, and adding some fresh potting soil. This will add a small amount of nutrient, and will spruce up the look of your terrarium as well.

Small rocks, moss and dried twigs make good decorations and add to the look of a micro-world of plant life. A terrarium can also be an ideal place to observe insects, but you will want to return them to the outside world after a few hours so they can survive in their natural habitat.

When your terrariums are finished, discuss the following: We only watered the soil in our terrariums once; how did the water get on the lid? Take your lid off the terrarium and feel the soil. Why is the soil still wet? Do you think that any water has evaporated from the soil? Why? If water evaporated, where did the evaporated water go? Did it ever rain in your terrarium? How do you know? Where did the rain come from? Is there anything in your terrarium that reminds you of a cloud or cloud drops?”

You may want to make a connection between the water cycle in the terrarium and in the real world with a discussion using the following: “If the terrarium is a model of the real world, what do you see outside that reminds you of the plant in our terrarium? reminds you of the soil in our terrarium? reminds you of the small water droplets on the lid? The soil in our terrarium stays moist, the ground outside never dries out completely. Why? What keeps it moist? Water collects on the lid of the terrarium, water also collects in the sky as clouds, where does the water in the clouds come from?

Keep your terrarium after the lesson is over and enjoy it for many months to come!