AIR & WEATHER
INVESTIGATION # 1
Literature Resources:
Additional Resources
INVESTIGATION 1 — Exploring Air
WHAT CAN AIR DO?
Air is difficult to pin down in order to verify its existence. It is, first of all, invisible, so you can’t look around to see where it is. Air is not very dense, so it is difficult to feel. Added to this, it does not make any noise by itself and has no taste or odor. Air can easily be overlooked. But you can observe air interacting with objects. Air can move from place to place (blow through a straw or tube), it can make light objects move (a piece of paper, a cotton ball, a feather, a leaf), and you can feel it when it hits your skin. Moving air is wind.
The best way to find out about air is to capture some in an airtight container and conduct some investigations. If the container is flexible, like a plastic bag or rubber balloon, you can feel the air inside. If you try to press the sides of the bag together, the air inside will prevent you from doing so. If you persist and apply enough force, the air inside will pushout on the sides of the bag until the plastic ruptures, allowing the air inside to escape. Similarly, the rubber balloon, which is more flexible, will deform and stretch when you apply force, until again the membrane ruptures, allowing the air to escape. In both cases it is an interesting experience to feel the strong resistance offered by the air and to note that the air feels “harder” as the pressure increases.
Part 1: Air Is There
Part 1: Air Is There
Introduce the air bags
- Call students to the rug. Hold up one bag containing objects.
- Tell students Today we are going to investigate the objects in this bag. Let’s see what is inside Remove the items one at a time and let students identify them. When the last object is out of the bag, make an issue of the “empty” bag.
- Ask, Is there anything else in the bag?
- Some students should report that there is some air in the bag. Have students compare a completely flat bag (with no air in it) to one that is puffy (with air).
- Ask, How can you tell when air is in a bag or another container?
- At the end of the discussion, tell students that everyone will get a bag of objects to use to see what they can find out about air.
FOCUS QUESTION: What can air do?
AIR BAGS
Review the safety guidelines for this part with students. Tell students,
- It is OK to blow through the straw, but don’t use the straw to blow on your neighbor. Straws should not be shared.
- Use a balloon pump to inflate a balloon. Don’t put a balloon in your mouth. The only thing you can put in your mouth is your own straw.
- Don’t release balloons in the classroom.
- Organize students into groups of four to six students. Assign one student from each group to be the Getter.
Have a Getter from each table get an air bag for each student. Make the balloon pumps available. Let the air exploration begin.
- As students explore the objects, encourage them to make observations and to describe how air interacts with each object. Provide a sentence frame such as
- “When _____, then ______ .”
- There will be many demonstrations of blowing things around with the straw—feather, ball, paper. Some objects may be launched into the air to float slowly to the ground. All activities that do not bother other students should be acknowledged and encouraged.
When students have exhausted their ideas, collect the plastic-foam balls and feathers. Have students put all the other materials in their bags. Ask them to write their name on the piece of paper so they will know which bag to take home. Students should store the bags in their desks. Keep one bag intact for the class discussion.
Discuss what air can do
Have them share some of their experiences with the objects and air. They might say that air filled the balloon or the bag; air pushed the cotton ball, paper, or feather around; air went through the straw; they could feel the air when it came out of the straw and the bag; and so on. After students have had time to express what air can do, provide more information.
Tell them,
- Air is a form of matter. There are three kinds of matter: solids, liquids, and gases. Air is an invisible mixture of gases. Help students identify some of their discoveries as evidence for the idea that air is matter.
- Air can move things from place to place.
- Air can fill up a plastic bag which cannot be smashed flat without letting the air out first.
- You can feel it when you blow through a straw onto the back of your hand.
Write these ideas on the board, and add any new words to the word wall.
Science Notebooks
Tell students that scientists keep a notebook to write about their science discoveries. Explain that every student will have his or her own notebook.
Distribute science notebooks to students. Give students a minute to confirm that the pages are all blank. Have students write the numbers 1–10 in the outside corner of the first ten pages, using the front and back of each page.
When the pages are numbered, call for attention. Restate the focus question that is written on the board.
What can air do?
Tell students that you have a sheet of paper with the question written on it. Describe and model how to glue notebook sheet 1 into the notebook.
a.Open your notebook to page 4.
b.Write the date on the top of the page.
c.Use a glue stick to put glue on the back of the sheet.
d.Stick the sheet below the date.
When students have their notebook sheets glued in place, read the focus question aloud together.
Vocabulary
air
blow
gas
matter
move
Notebook Entry
Students write and/or draw something that provides evidence that air is matter. For example, air can move things; air can fill a balloon or a bag (the balloon or the bag goes flat when the air goes out); when air moves, you can feel it.
Part 2: Parachutes
How Does a Parachute Interact with Air?
Discuss parachutes
Gather students
If you needed to drop a box of food and water from an airplane for some firefighters, what do you think might happen? [The box would crash to the ground and everything would probably break and spill.]
What could you do to solve the problem and deliver the box to the ground gently? [Maybe use a helicopter or drop the box with a parachute.]
What is a parachute? Where have you seen one? [A parachute is like a big sheet that carries things to the ground slowly. Skydivers use parachutes when they jump out of airplanes.]
Show the parachutes video
How does a parachute work?
Listen to students’ answers, encouraging any answers that include something about air pushing or holding the parachute up.
Introduce an engineering challenge
Tell students:
As soon as people began flying in small airplanes, they were faced with a problem. How could a person escape from an airplane that was in trouble? How could a person return safely to the ground without the plane? Or how could anything else that you wanted to send from a plane get back to the ground and land safely?
Explain that students will be engineers and come up with a solution to this problem. Ask students what they think engineers do. Some will say engineers drive trains. Confirm that this is true, but point out that most engineers are people who design things to solve problems for people. Provide a few examples. You can use the design of a pencil—someone engineered a machine that places the metal band on the wooden pencil to hold the eraser on the wooden shaft. Another type of engineer created and tested the rubber to make an eraser.
Introduce parachute design with a think-aloud
- Tell students that they are each going to make a parachute. As a class they will come up with a design. Hold up and name the materials. Open and display a paper napkin and say, We might be able to use this napkin as a canopy for a model parachute.
- This paper clip might serve as a model person to ride down through the air on the parachute.
- What do we have that might serve as the cords to connect the canopy to the person? [The string.]
- Now we need to have a way to attach the string to the canopy. Any suggestions? [Adhesive dots.] Let’s attach one string to each of the four corners of the canopy. Show students how to attach the string to the napkins using an adhesive dot.
- Now that we have string on the four corners of my canopy, what should I do next? [Attach the person with the strings.] I will gather the ends of all four strings and tie them together. I’m not so good with tying knots, so I could use one of the adhesive dots to hold the four strings together.
- Now I can take the bundle of four strings in the dot and run it through a jumbo paper clip. I’ll fold up the bundle of string to form a loop. I can tie the string around the paper clip using an overhand knot, or use a dot to secure the clip to the strings.
- Hold up the finished parachute by the top center of the canopy. Tell students the parachute is a system, made up of different parts that work together. Ask,
Do you think this is a good parachute design? How can we find out?
When student’s suggest it, hold the parachute high and release it to glide slowly to the floor.
Review the process of engineering.
- We defined the problem.
- We came up with a plan for a solution.
- We built the solution.
- We tested the solution to see if it worked.
You just watched and helped me engineer a solution to the problem of how to drop a load or passenger safely through the air. Now it is your turn to build your own parachute.
List the materials that each student can use and the procedure for getting materials. Have students get the materials, return to their tables, and begin building parachutes. Circulate around the room, offering encouragement and guidance as needed.
Fly parachutes
When the parachutes are ready, let students begin releasing them. If students are having problems releasing the parachutes, show them how to hold the paper napkins so the strings and paper clip hang down. Then lift the paper napkin as high as you can and gently release it. As students release the parachutes, you will need to troubleshoot problems, such as tangled or loose strings, torn paper napkins, and so on.
If students finish testing their parachutes early, suggest they try using two “passengers” and talk with a friend about the effect of doubling the load.
Introduce air resistance
- After a period of parachute flying, have students leave their parachutes at their tables and return to the rug.
- Ask,What happened when you flew your parachute? [It fell or floated to the floor.]
What made the parachute float down so slowly? [Air.]
Where is the air? [All around the parachute.]
Did you notice a difference between flying one and two passengers?
What was different?
Tell student:
- When you drop a paper clip by itself, it does not have to push very much air out of its way as it falls. When the same paper clip is attached to a parachute, the system is large so it has to push a lot of air out of the way to fall and so it falls much more slowly.
- Add parachute, air resistance, system, and push to the word wall. Ask students to share other examples of air resistance, such as a balloon or feather floating slowly to the ground or a person trying to walk against a strong breeze.
Focus question: How does a parachute interact with air?
Outdoor test
Suggest that the class go outdoors to fly the parachutes. Review the procedures and behaviors for outdoor learning. Refer to the Outdoor Safety poster provided in the kit. In addition, highlight these guidelines.
- Remember who your outdoor discovery buddy is.
- Walk quickly and quietly to the outdoor starting place.
- Start by forming a sharing circle—hands on hips, elbows touching.
- Wait for further instructions.
- When you hear the signal (whistle, bell, etc.), quickly return to the sharing circle.
Have students line up in buddy pairs. Pick up your bag of extra parachute supplies. March outside, using your outdoor learning door. Form a sharing circle. If sunshine is bright, take a position in the sharing circle where you are facing into the sunshine. Describe the boundaries of the launch area and review any flight rules for using parachutes outdoors.
Give students several minutes to fly their parachutes in the designated location.
Visit the pairs and offer some challenges, such as
Can you keep your parachute in the air for more than 5 seconds?
Can your parachute travel more than five large steps away from you?
Can your parachute go higher than your hands above your head?
If a parachute is doing something interesting, draw attention to it.
What is different about flying a parachute outdoors compared to indoors?
Vocabulary
air resistance
engineer
parachute
push
system
wind
Science Notebook
Distribute a copy of notebook sheet 2, Parachutes, to each student. Call attention to the picture of the parachute on the sheet. Restate the focus question that is written on the board, and have students refer to the question on the notebook sheet.
How does a parachute interact with air?
Describe and model how to glue the sheet into the notebook.
a.Open your notebook to the next blank page.
b.Write the date on the top of the page.
c.Use a glue stick to glue the sheet into the notebook below the date.
Part 3: Pushing on Air
What Happens When Air Is Pushed into a Smaller Space?
In a rigid cylinder fitted with an airtight piston, like a syringe or a bicycle pump, air can be explored in other ways. If there is no outlet for the air, the descending piston will push the air into a smaller space. Each additional increment of distance that the piston moves will be harder to achieve than the previous one. This is because the air is being compressed. If the air is subjected to enough pressure, it will liquefy.
Two syringes connected with a short piece of tube form a system that can be used to investigate the effects of air pressure. When assembled with the plunger pushed in all the way on one syringe barrel and pulled out all the way on the other syringe barrel, air can be pushed back and forth between the two syringes. This investigation provides visual and tactile evidence that air is real stuff and that it can be used to move things around.
Introduce the syringes
- Call students to the rug. Tell them that today they will use a new tool to find out more about air. Bring out a syringe and show them how the plunger can travel up and down in the barrel. Show them a flexible tube, but don’t show them how to connect it to the syringe. Tell them that each student will get a syringe and a tube. Establish safety rules for using syringes.
- Tell students that they should use the new tools to find out what they can about air. Do not provide any additional guidance—just let them explore the new materials.
- Assign Getters and let them get one syringe and one tube for each student at their table. Let the exploration begin.
- Allow about 10 minutes for exploration. Visit students as they work. Encourage them to show you what they have discovered.
- The tube fits on the tip of the syringe.
- The plunger can be pulled out of the barrel.
- Air can be pushed out of the tube with the plunger; you can feel it.
Focus question: What happens when air is pushed into a smaller space?
Observe students working with two syringes
Visit students as they work. Encourage the pairs of students to show you what they discover.
- Two syringes can be fitted to one tube.
- Pushing and pulling one plunger can make the other plunger go in and out. The air moves from one syringe to another.
- Air wrestling—a game when two people both push at the same time. The air goes into a smaller space but pushes back.
- The pop off—launching one plunger with air pressure. The air doesn’t stay in the smaller space but pushes the plunger out.
- When students discover the pop off, call for attention and issue a convincing safety warning. Model how to aim the syringes away from other students.
As you visit the groups, introduce pressure and compress into the conversations.
- Air wrestling sure puts a lot of pressure on the air in the syringes.
- Can you compress all the air into one of the syringes?
- What might happen if you put too much pressure on the plunger?
Discuss the two-syringe system
Call students to the rug. Have one two-syringe system to use during the discussion. Attach two syringes, one with the plunger all the way in, and the other all the way out. Introduce this as a system—parts that work together. Push the extended plunger in to see the other syringe’s plunger push out. Ask,
What is happening to the air inside the syringe system? [The plunger pushes the air into the other syringe.]
Discuss air wrestling
Push one plunger all the way down and hold it there firmly. Push on the other plunger to show that air can be pressed into a smaller space. Ask,
Is there more air in the system now (with the air compressed) or now (with the pressure released so the plunger can return to its starting position)?
Add words that students use to the word wall. After students offer their ideas, tell them,
The amount of air in the system doesn’t change; it stays the same all the time. No air can get out of the system, and no new air can get in. What happens is that the air gets pushed into a smaller space.
What causes the plunger to move back out?
Listen to students’ ideas. Then offer this explanation.
When all the air is pushed into one of the syringes, we say it is compressed. Compressed air pushes back with pressure. It is the air pressure that can push the plunger back out when you release it.
Add compress, pressure, and system to the word wall along with tube, syringe, plunger, and barrel.
Pull both plungers out of the barrels and replace them only far enough to get the rubber tips into the barrels. Ask,
What will happen if I increase the pressure in the system by pushing one of the plungers in?
Do it to demonstrate that air pressure can push the other plunger out of its barrel. As a conclusion to the discussion, ask students to explain why the plunger pops and flies through the air. [Plunging one syringe compresses the air in the system, creating pressure, which forces the other plunger out of its barrel.]
Vocabulary
barrel
compress
plunger
pressure
syringe
tube
Science Notebook
Part 4: Air and Water
How Can Water Be Used to Show That Air Takes up Space?
Imagine a mayonnaise jar with a hole in the lid just the right size to fit a funnel. When the lid is screwed on tightly, the system is airtight except for the passage through the funnel. If you attempt to pour water into the jar through the funnel, the water will just sit in the funnel. The water cannot flow into the bottle because the bottle is already full of air. There is no place for the water. If you poke a second hole in the lid, the water will flow in as the air escapes through the hole. The denser water displaces the air in the bottle.
Gases by their very nature are less dense than liquids, so when gases and liquids are mixed, gases rise to the top and liquids settle to the bottom (except for small amounts of gas that may dissolve in the liquid). If the gas is introduced into the liquid below the surface, the gas rises to the surface in a characteristic form known as a bubble. Every toddler discovers this engaging phenomenon when he or she is learning to drink milk through a straw. Air blown in the milk forms bubbles that rise to the top and fill the glass, and if the source of air is persistent, the bubbles may flow over the rim and onto the table.
Vial Demonstrations
- Review what was learned about air with the syringes, the idea that air takes up space, and especially the ideas of pressure and compression.
- Hold up the vial with no cap (open) and ask what is in it. Confirm that the vial is filled with air. Show students the basin of water and make sure that everyone can see the demonstration clearly. Crumple a quarter piece of paper towel and push it into the bottom of the vial. Then turn the vial upside down so the open side is just above the water.
Ask, What do you think will happen if I push the vial into the water? I will submerge the vial in the water. What will happen to the air inside the vial?
What will happen to the paper towel in the vial?
- Listen to some ideas and the explanations students provide for their ideas. Then ask students to watch closely as you push the vial under the water. Keep the vial straight up and down when you put it under the water, then take it back out again. Dry off the outside of the vial and pass it around so students can view the paper towel inside. Repeat this process with several other vials with paper towels inside so that everyone has a chance to observe and feel the result.
- Ask students to discuss why they think the paper towel did not get wet. Ask for a few volunteers to draw a picture (or model) on the board to explain their thinking (or have them tell you what to draw).
- The plastic-foam ball can help students see the water level in the vial. Float the ball on the water, then place the vial upside down over the ball and push down into the water.
- Ask students to observe and describe the relative position of the ball in relation to the surface of the water and in relation to its position in the vial. Students should do this also when the vial is above the water and when it is below the water surface.
- Repeat this process several times and have some students do the demonstration for the class. Try letting out a few bubbles, and watch the water level in the vial rise.
Discuss observations about air
- Is there air in the vial? How do you know?
- If you push the vial straight down into the water, is the air still in the vial? How do you know?
- How did it feel when you pushed the vial upside down into the water? [Have those students who participated in the vial-and-ball demonstration respond to this question.]
- What caused the paper towel to stay dry?
- Where do the bubbles come from?
Introduce the vial-and-water center
Focus question: How can water be used to show that air takes up space?
How can water be used to show that air takes up space?
Students should describe the demonstrations when the dry paper towel in the vial was pushed under the water and when the bubbles came from the upside-down vial when it was tipped under the water. The idea students should convey is that the air in the vial can be pushed into a smaller space, but it still takes up space in the vial.
Introduce the bottle system
- Tell students that they will continue their investigation of air by using some new materials. Show them a bottle and rubber stopper with one long pipe and one short pipe inserted in the stopper (no syringes attached).
- Ask,What is in this bottle? Can air get in and out?
- Now that students have observed the bottle with pipes, demonstrate as you describe how you assembled the bottle system.
I put the stopper into the bottle loosely.
I pushed the long pipe down to the bottom of the bottle, and I pushed the short pipe in so it matches the top of the long pipe
I pushed and twisted the stopper into the bottle to make it tight.
I put a tube on each pipe.
I put a syringe on each tube.
Tell students that this is one way to connect two syringes. Ask students how the bottle system compares to two syringes that are put together with just one tube. Students should see that the bottle can hold a lot more air than a tube. Ask,
- What will happen if I pull up on one of the plungers?
- What will happen to the air in the bottle?
- What will happen if I push the plunger down into the syringe?
- What will happen to the air in the bottle?
- What will happen to the other syringe?
Have two students participate in the class demonstration. Move the plungers in and out of the syringes, and each time have a volunteer describe what they observe and explain what is happening to the air. Because air can be compressed and because there is so much air in the system, students will not see the same kind of action they did with the simple system of two syringes and a tube.
Begin Investigation
- Hold up a vial half full of green water. Tell students you added food coloring to the water to make it easier to observe. Tell them that they can add water to the bottle system. Show them how to use the syringe barrel (plunger removed) connected to the short tube to act like a funnel to direct the green water into the bottle.
- Tell students that each pair will get a bottle system and that they should explore what happens when they add water. Remind them of the focus question.
- Send students to their seats. Assign Getters to get a bottle system for each pair of students.
- Visit each pair of students and provide a vial half filled with green water. Remind them to use the bottle system carefully.
- Visit the pairs of students as they get their bottle systems working. Share in the discoveries. Encourage students to explain each of the interesting actions they observe in terms of what is happening to the air in the system.
- water standing in the syringe barrel and not flowing down into the bottle;
- water flowing through the syringe barrel into the bottle;
- air bubbling through the water in the bottle;
- water drawn up into the syringe;
- water pushed up into a syringe or out of the tubing onto the table
Discussion
Have one bottle-syringe-water system to use during the discussion. Set up the system as illustrated, syringe with plunger pushed in on the long-pipe side; empty barrel attached to the short pipe. Pour water into the empty barrel. The water does not flow into the bottle. Ask students to explain why. Refer to the models on the board and ask them to think about how they might help them explain why the water won’t go into the bottle. Ask,
What is in the bottle?
Guide students to this understanding. The bottle is already full of air, so there is no place for the water to go. Air is matter and occupies space even though we can’t see it.
Discuss why water will flow into the bottle
Repeat the demonstration, but this time remove the plunger from both syringes before pouring water into the barrel attached to the long pipe. The water flows right into the bottle.
Ask students to turn to the person next to them and discuss their models that explain why the water will flow into the bottle.
Ask, What is different about the system now than before? Where is the air?
Explain, Air escapes out the open syringe as water flows in. The water flowing into the bottle pushes the air through the short tube and out the open syringe.
Use the syringe attached to the long pipe to draw water into the syringe. Explain, The water is sucked up into the syringe through the pipe that goes to the bottom of the bottle.
(Although not scientifically accurate, this explanation is just fine for primary students.)
Now change the system. This time, use a syringe to push air into the bottle (short pipe) and water out of the bottle (long pipe). Have students take turns telling a neighbor what caused the water to go out.
Explain,
When air is pushed into the bottle through the short pipe, the pressure in the bottle increases. The pressure on the water pushes the water up the long pipe and into (and out of) the open syringe.
Science Notebook
Call attention to the two pictures, one with a vial under water and the other with two syringes. Tell students that they can answer the focus question by describing what is happening in one or both of the pictures. Restate the focus question that is written on the board and have students refer to the question on the sheet.
How can water be used to show that air takes up space?
What to Look For
Students demonstrate that they understand that air takes up space. For example, they explain that the water couldn’t go in the vial until it was tipped and some of the air released; they describe how air pushed water around in the bottle system; they say that air and water cannot take up the same space at the same time.
Vocabulary
bubble
submerge