Not-so-messy hands-on science: four fascinating and fun science activities that guarantee twice the science learning with only half the mess.

Newspapers are spread over tabletops and floor tiling to catch any stray dirt, sand, and gravel that might spill as students investigate "nature's underground washing machine"-that is, how rainwater that seeps into the ground is made drinkable again. All around the room there are exclamations of excitement. "Cool! Hey, pour some more dirt in here." "Shelly, will you pass the gravel?" "Wow! Look at how different the water looks now!" Over the din the teacher says, ''Five more minutes until clean-up."

Inquiry-based learning in science can lead to a classroom that, on the surface, is busier and noisier than usual. But with the following easy, step-by-step experiments, and the establishment of clear-cut rules, goals, and procedures, teachers can fully engage students' wonder and energy while maintaining a productive and manageable learning environment.

EXPERIMENT #1

Speaking of Beaks

Focus: Animal adaptations

Purpose: Students examine how birds' beaks are adapted to suit their habitats.

Each Group Will Need

* One small paper cup per child.

* Books, magazines, and newspapers showing a variety of birds.

* Bird "beaks" (e.g., spoons, clothespins, toothpicks, craft sticks, tongue depressors, tweezers, chopsticks, straws, and plastic forks, either whole or with a couple of tines broken off.)

* Bird "foods" (e.g., actual bird seed, jelly beans, raisins, dry macaroni, foam packing, peanuts, a cup of fruit juice or water, gummy worms, and so on.)

What to Do:

1. Discuss the "utensils" humans eat with. Would we eat soup with a fork? Steak with a spoon? Why or why not?

2. Make a chart showing specific bird beaks alongside a list of foods that each of these birds eats.

3. Organize students into small groups to act as nests of birds.

4. Have each group's getter (see "Management Tips," opposite) select a variety of beaks from the Materials Table. Leave the "foods" on the Materials Table, or elsewhere in the room.

5. Tell students that, one at a time, they will take turns acting as the "Mama" or "Papa" bird, selecting a "beak" and "flying" to the foods. The goal is to see how much chow they can carry in their beaks, using only one hand, to their babies' cups. Scatter newspapers for easy clean-up of any dropped food.

6. After everyone has had a turn as parent bird and has experimented with a variety of beaks, ask: Which type of food was easiest to carry? Did certain beaks work best with certain foods? Why?

7. Have students look back at the chart they made, and compare the pseudo beaks kids made with some actual bird beaks. How do the types of foods these birds eat compare?

EXPERIMENT #2

Nature's Underground Washing Machine

Focus: The water cycle

Purpose: To mimic the way nature cleans rainwater that seeps into the ground.

Each Group Will Need

* One paper coffee filter.

* A rubber band.

* A clear plastic two-liter soda bottle with the bottom cur off.

* An empty container.

* Materials to represent layers of earth (e.g., gravel, sand, pebbles, twigs, grass).

* A mixture of soil and water

What to Do:

1. Discuss with students the differences between groundwater and surface water. When it rains, some water falls directly into lakes, rivers, and streams. This is called surface water. Much of the rest of the water is absorbed into the soil, and seeps underground. This groundwater is stored in materials such as gravel and sand. In this activity, students will see how nature helps to make the water that is pumped from the ground clean.

2. Using a rubber band, have students attach a coffee filter to the neck of the soda bottle. Students should then place the bottle, with the attached filter down, in an empty container.

3. Direct students to fill their bottles with shallow layers of gravel, sand, twigs, and grass clippings.

4. Next, have students mix a concoction of dirt and water, and predict what will happen when they pour it through the layers of earth they've just made.

5. Have students slowly pour half of the dirty water into the bottle, recording how quickly it flows through the system of layers, and how the water in the container compares with the dirty water. (Caution students that the water they cleaned is still not safe to drink.)

EXPERIMENT #3

Ecosystem in a Bottle

Focus: Aquatic ecosystems

Purpose: To observe changes over time in an aquatic habitat.

Each Group Will Need

* Two 2-liter soda bottles.

* Dechlorinated water.

* A light source.

* One male and one female guppy.

* Elodea.

* Duckweed or a suitable substitute (available at pet supply stores).

* Water snails.

* Sand.

* Scissors.

* Graph paper.

What to Do:

1. Cut the top off one bottle at the shoulder (where it tapers). Cut the base off another bottle and score it with holes. This is the cover.

2. Fill the bottom of the bottle with sand, two-inches deep.

3. Slowly add water (to minimize sand displacement).

4. Root three elodea stalks in the sand, and sprinkle a small amount of duck-weed onto the water's surface.

5. Let the sand settle overnight.

6. Add two guppies and two snails.

7. Over a four-week period, have students record daily observations of what they see. Ask: Have there been any population changes? Plant growth? Color, or other changes, in the water?

8. At the end of the period, have student groups graph and compare any quantifiable data they've obtained.

EXPERIMENT #4

Habitats Out of Whack 

Focus: Animal habitats

Purpose: To demonstrate all living beings' need for food, water, shelter, and space to live in.

Each Group Will Need

* Index cards, in four different colors.

* Heavy tape.

What to Do:

1. Ask students to help you define the word habitat, and to give examples.

2. Organize groups of four, and tape a different-color index card to the students within each group. Each color card represents one of the four components of a habitat--food, water, shelter, and space.

3. Using the list of habitats they brainstormed, challenge students to name some places in each habitat where they might find the four components.

4. Have the kids form one large circle, making certain to alternate habitat components. Then have everyone take one step toward the center of the circle and take hold of the shoulders of the person in front of him or her.

5. On the count of three, have the students sit down on the knees of the person behind them, while the people in front of them sit on their knees. (This may take some Practice!) Point out that this works because each member of the circle is supporting everyone else.

6. Have kids stand up, then ask volunteers to suggest things that can go wrong in a habitat. For example, water can be polluted; people can tear down trees. Select one of these, and ask kids which aspect of the habitat this would ruin. Have one or more students holding that particular habitat index card leave the circle. Then repeat the "lap sit." Now ask students to explain, in their own words, why the habitat "circle" fell apart this rime.

RELATED ARTICLE: MANAGEMENT TIPS

Materials

Post a Materials Chart itemizing everything students will need.

Set out and organize these materials in advance on a Materials Table.

Designate a "getter"--a student who goes to the Materials Table for anything his or her group will need.

Provide lunch trays or other containers for your class getters to use to carry back a group's materials.

Appoint a "clean-up leader" for each team, to assign clean-up tasks.

Getting Started

Review the instructions with students, and allow time for questions.

Distribute written instructions before students start working.

Establish a signal for students to use if they want your assistance. For example, glue a life-sized cardboard hand, or a large question mark, to a craft stick and distribute one to each group for kids to raise.

Use a signal to inform students when you need their immediate attention. My personal preference is the magic word "Salame," which stands for "Stop and Look At Me."

Clean-Up Time

Warn students five minutes (or more) before it's time to stop.

Post a chart listing chores cleanup leaders need to assign.

Ask students to show that they have finished cleaning by quietly looking back over the notes they made during the experiment, and to clarify them as needed.

Denise Bryan and Amy Denty are the South Dakota (1928) and Georgia (2000) State Teachers of the Year, respectively. Scholastic is the proud corporate sponsor of the National Teacher of the Year Program (NTOY). Administered by the Council of Chief State School Officers, NTOY is the oldest and most prestigious program of its kind, honaring teaching excellence for more than 50 years.