FOCUS: The air we breathe is part of the Earth’s atmosphere, a layer of gases that surrounds the planet, protecting us from harmful radiation and keeping us warm. Although air is invisible, we’ll discover that it takes up space, exerts pressure and has weight, can be heated, cooled and compressed, and that it always seeks to equalize its pressure. It is important to understand our atmosphere because without air, animals and plants could not survive. Introduction: Ask the children, “What are some things you notice about air?” PUPPET SHOW “ Half Full or Half Empty?” Objective: To learn how air is important to living things. Perform the puppet show, or have a group of children perform it for the class. Afterward, ask questions to review the key details and vocabulary in the story. Why is air needed by animals? (for energy) By plants? (to make leaves, stems, etc.) Holding up each puppet, review how each one gets air. What is the part of air that people and animals especially need to breathe? (oxygen) Materials: puppets, script, stage, props. LUNG ACTION DEMO (grades 3-6) Objective: To use a model to understand how our lungs function. Use the Lung Diagram and Lung Diagram Explanation to explain how our lungs work. Now hold up a lung model* and explain that the inner balloon is like a lung, and the large balloon is like our diaphragm. Have a child try pulling the diaphragm downwards, and then pushing it upwards. What happens to the small (lung) balloon when the diaphragm is pulled down? (It fills with air.) What happens to it when the diaphragm is pushed upwards? (It deflates.) How might our lungs and diaphragm work? (When we move our diaphragm downward, air flows into our lungs; when we move the diaphragm up, air flows out again. We do this automatically, without thinking about it.) *Lung model: Cut off the bottom of a small plastic water bottle. Drill a hole in the bottle cap just big enough to fit a plastic drinking straw. Insert the straw through the hole and use clay to make an airtight seal. Securely attach a small (2”) balloon to the lower end of the straw with a rubber band or tape. The bottle is like our chest cavity, and the balloon on the end of the straw represents the lungs. Cut off a 5-9” balloon at the widest part and stretch this tightly over the bottom of the bottle. Secure with duct tape. This balloon acts as the diaphragm, the large muscle below our lungs. Materials: Lung Diagram and Lung Diagram Explanation, liter plastic water bottle with cap, plastic straw, drill and bit to make a hole for the straw, 2” balloon, modeling clay, rubber band, 5-9” balloon, duct tape. AIRY ACTS Objective: To model some additional ways that air is important to living things. Besides needing air to breathe, animals and plants make use of the air for different purposes. Divide the class into small groups and have each team practice a short skit to demonstrate a way that air is important to their animal or plant. Give each group one of the following scenarios: Airy Act 1: Rabbits and hares keep warm when the cold wind blows in winter because they have fur, which traps warm air close to their bodies. (keeping warm) Airy Act 2: Insects buzz their wings to fly through the air. Birds flap their wings, using air to fly and chase flying insects. (flying) Airy Act 3: Crickets rub their wings together to make sound waves that are carried by the air. Sounds help them to find each other. (carrying sound) Airy Act 4: Skunks lift their tails and give a puff of scent when frightened. Air carries the smell and scares off their enemies. (carrying odors) Airy Act 5: Trees make seeds with wings that spin. The air carries their seeds to places where they can grow. (carrying seeds) After each skit, ask the rest of the class to identify the function of air that was demonstrated. Materials: Airy Acts Skit Cards, props including furry clothing, craft feathers, combs, skunk tail cut-outs, helicopter seed cut-outs; optional: insect costume such as bug-eye glasses and antennae. MOLECULE DANCE Objective: To model the behavior of molecules in a solid, liquid and gas. Everything in the world is made of molecules, tiny particles too small to see even with a microscope. Explain that the group is going to act out what it’s like to be a molecule in a solid, like a rock; in a liquid, like water; and in a gas, like air. In a solid the molecules are touching and bonded together. Have the children form a close group, touching elbows and crowding together. They can’t detach from neighbors and move around, but they do vibrate (jiggle) in place. In a liquid the molecules don’t stick tightly to neighbors and can slide past each other. Have children move around in slow motion, no longer touching elbows. A liquid fills its container, and flows downhill if it tilts. In a gas, the molecules are widely spaced and they can move around in all directions, including upwards. They don’t touch unless they bump into each other or into something else. When they bump into an object or a wall, they turn and go a different way. Have everyone move around freely, reversing directions when they touch something. Continue until everyone has spread out to fill the room. When they are warm they move faster; when they cool off they have less energy and get closer together, though not as close as in a liquid. What would happen if a door was opened? (Some of the gas would go out.) STATIONS: The following activities are best done in small groups and could be set up in stations: Paper Flip, Air Trap, Pump Action, Rise and Fall, and Diving Dropper. PAPER FLIP Objective: To use a model to see that air has weight and exerts pressure on a surface. Spread out a section of newspaper on a table so that it is as flat as possible, and so that one edge is even with the edge of the table. Carefully slide a wooden paint stick under the paper so that about 1/3 of the handle sticks out. Ask the children if a lot of strength would be needed to flip the paper into the air with the paint stick. Now have a child give one quick rap with the side of the hand against the wooden paint stick. Does the paper fly up into the air? (usually not) Could the child feel a weight pressing against the stick? What happens when you press on the stick slowly so that air gets under the paper? (It is easier to flip.) Try lifting the paper with the stick to feel its weight. Is the paper heavy? Try folding it into quarters. Now you have made it smaller, but it is still the same weight. Have the children stand back and have an adult hit the stick gently to flip the paper. (Caution: the stick flies out more easily now.) When it’s folded, the paper is easy to flip, but when it is spread out, it is hard to move. What is holding it down? (air) Because air is a gas, air pushes in all directions. When you slowly press the stick, air gets under the paper and pushes against it from underneath, with a pressure equal to the air pressing from above – so you only feel the weight of the paper itself. For older students: Explain that a one inch column of air extending from sea level to the farthest edges of the atmosphere exerts a pressure of 14.7 pounds, or about a ton of pressure on every square foot of ground. Ask for ideas about how they could calculate the weight of air pressing on the newspaper. Have students measure the area of the paper (length x width in inches), then multiply the area by air pressure at sea level (14.7 lb/in²). This is how many pounds of pressure the air is exerting on the spread out newspaper. Materials: Several sections of newspaper, wooden paint sticks; optional for older children: rulers or yard sticks, calculators, pencils, paper. AIR TRAP Objective: To use a model to see that air takes up space and can be compressed. Working in small groups, hold up a plastic bag, preferably with a zip closing, from which you have squeezed out the air so that it is flat. Now open the bag, separating the sides, and then close it with the zipper. Pass the bag around and let the children feel the puffed- out sides of the bag. What is keeping them from squeezing the bag flat? (the air in it) Does air take up space? (yes) Ahead of time, fill a small aquarium or basin with water. Now hold up a clear glass or plastic drinking cup. Stuff a tissue into the glass so that it stays in the bottom, even when you hold the glass upside down. Carefully press the glass downwards into the aquarium until it is submerged. Ask the children to look carefully and notice whether the water goes up into the inverted cup. (a tiny bit) Lift the cup straight out of the water, keeping it inverted, and pull out the tissue. Is it wet or dry? (dry) Why doesn’t the water get inside? (air in the glass is blocking the way) Now have the children take turns pushing the cup of air into the water to feel the resistance, and watch to see if it fills with water.