Air Pressure and Aeronautics Lesson
This is part 3 of a 5 part hands-on unit study on Floating & Flying. Discover the properties and power of air as you watch as air pressure blows up a balloon, sucks an egg into a bottle, collapses a can, holds water in an upside-down glass, and more! My lessons are geared toward 4th-5th grade level children and their siblings. These are lessons I created to do with a weekly homeschool co-op. We meet each week for 2 1/2 hours and have 33 children between the ages of 1-13. Use these fun lessons with your classroom, family, after school program, camp, or co-op!
The Holy Spirit and Air Are Both Real
1. Pray. Read & discuss John 3:8. How do you know if something is real? [Pull out one of the chairs.] How do you know that this chair is real? [Children will probably say that they can see it and touch it.] Is that the case with everything? Can anything think of something that is real that we can’t see or feel? [Allow children to share ideas.] If we can’t see or feel something, how do we know it really does exist? [Allow children to share ideas.] In this passage, a priest named Nicodemus meets with Jesus and asks Jesus how he can be saved. Jesus tells Nicodemus that he must be born again. Nicodemus doesn’t understand what that means, so Jesus tells him that his dead, sinful soul needs to be brought to life by being born in the Spirit of God. Sin in the world caused all of us to be born spiritually dead. The only way to be reconciled to God is to be born again, by receiving Jesus and His work on the cross for our sins. Our spirit is brought to life when we ask Jesus to come into our lives and forgive us our sins. At that time the Holy Spirit comes into our lives and gives us spiritual life; we are born again spiritually. The Holy Spirit comes in and gives new life! The Holy Spirit helps us to obey God. He transforms us into new creatures and we are born again. This transformation happens in us by simple faith when we accept Jesus as our Savior. We may not see this new birth or watch it as it happens but we will be able to see the effects of the Spirit in our lives. We'll know we are born again by the changes the Holy Spirit makes in us. Can you see air or the wind? [No.] Can you hold it in your hand? [No.] Can you taste it? [No.] How do you know wind exists, that wind is real? You see the effects of it. You can see branches or leaves moving when it blows. You can see a balloon get bigger when you blow air into it. We don't see air or the wind visibly, but we do see their effects. When we believe in Jesus, we are saved by the work of salvation He did on the cross for us. We are no longer condemned; the death sentence our sin requires is pardoned because of the blood of Jesus Christ.
2. Review what we learned last week about ships and boats by asking, “What was something you learned about boats last week?” [Allow a few children to answer]
3. A couple weeks ago we learned about water and water pressure. Today we are going to learn about air and air pressure. Read “Air Is All Around You” by Franklyn M. Branley.
YOU WILL NEED: “Air Is All Around You” by Franklyn M. Branley
This gives a good overview of air and air pressure and has nice illustrations.
This would be another good option for a read aloud book to introduce the concept of air and air pressure.
Air Is a Real Substance: Hot Air Blows Up a Balloon
4. (Prep: Bring water to a boil in a pan.) Ask children to give you evidence that air is real. Let a few children share their ideas.
-Show the children 2 bottles. Place a pencil in one of the bottles. Ask the children, “Which bottle is empty?”
-Place a balloon over the top of the “empty” bottle and then set it in the pan of very hot boiling water. Ask the children to describe what they observe. (The balloon should slowly inflate.)
-Ask, “How did this happen? If the bottle was empty, then how can this balloon get filled?” (As the air is heated, the air molecules spread apart/expand.)
-Tell the children that this shows that air exists. It is a real substance.
YOU WILL NEED: two 2L bottles, pencil, balloon, pot of boiling/very hot water
Air Is a Real Substance: Pouring Air
5. (Prep: Fill the plastic containers about 3/4 full of water.) Anyone can pour water from one cup to the next, but can you pour air?
-Divide children into 8 groups of 3 children each. Give each group 2 glasses and a container of water and tell them to pour air from one glass to the other. Tell them that this is not only possible, but if they do it right they will be sure that air is being poured.
-If children need assistance, suggest they use their containers of water. Let them first experiment a minute or two to try to figure out how to do this.
-If no one can figure it out, instruct them that they must pour the air underwater. Invert the first glass and push it underwater. It is filled with air. Lower another glass underwater in an upright position. After it fills with water, invert it above the first glass. By lifting it carefully, upside down, until its mouth is just under the surface, you will have a full glass of water with its bottom up above the water line. Slowly tip the first glass (filled with air) so that the bubbles stream upward into the second glass and push the water out. They are “pouring” air.
-Tell the children that this shows that air exists. It is a real substance.
YOU WILL NEED: drinking glasses and containers of water
Air Takes Up Space: Air Keeps a Paper Towel Dry
6. Give each group a couple paper towels and tell them to push the paper towel under the water without getting it wet. Let them first experiment a minute or two to try to figure out how to do this. This is similar to the above activity.
-If no one figures it out, encourage them to use the glass. They should wad up the paper towel, place it inside the glass making sure to have pushed it securely against the bottom so that it will not fall down, and then invert and submerge the glass. The air keeps the water out.
-Tell the children that this shows that air does take up space.
YOU WILL NEED: paper towels & items used in above activity
Air Exerts Pressure: Collapsing Cans
7. (Prep: Place a small amount of water in each can. Heat the aluminum soda cans over the stove until they are very hot. Have them continue to heat up until you do the demo. Place a bowl of ice water on the island in the kitchen.)
-Have children come into the kitchen and stand around the island in the kitchen so they can see.
-Use tongs to quickly plunge the first can upside down into the cold ice water. Ask, “What happened to the can?” (It should collapse. Try with a back-up one if the first one didn’t collapse.)
-Ask, “Why do you think that happened?”
-Repeat with the second and/or third can (simply because the kids love watching this.)
-Explain what just happened by saying something like the following: Air exerts pressure. Where does the pressure come from? It comes from the weight of air. Ask the children if they think air is heavy. If you have enough of it, air can be a powerful force. The pressure comes from the weight of hundreds of kilometers of air pushing down from the earth. At sea level the pressure of air is so great that it pushes with a force of 1 kilogram per square centimeter. The total force on the can may have reached more than 1800 kilograms per square centimeter. If air pressure is so great, then why aren’t we crushed by it? Not only does it leave us uncrushed, we can’t even feel it! The reason is because the air pressure that is pushing down on us is equaled by the pressure within our bodies pushing outward. Only in rare cases when pressures are not equal do we notice it. Ask if anyone has ever felt their ears “pop” when going up or down a mountain or in an airplane. Air pressure varies with elevation, so those changes can sometimes be noticed. If you can create a situation where normal air pressure is removed, then the existing air pressure can exert itself. That is how the air crushed the can. A little bit of water had been placed in the can. As the water was brought to a boil, the can quickly filled with steam which pushed out all the air. When the steam is cooled off by the cold water, it condenses into a few drops of water, leaving a vacuum in its place. The air crushes the can as it tries to get inside.
-Tell the children that this shows that air exerts pressure.
YOU WILL NEED: mixing bowl of cold ice water, 3 empty aluminum soda cans, tongs
Air Pressure & Straws
8. (Prep: Pour water into the 24 cups. Place a straw in each cup. 12 cups should have regular straws and 12 cups should have straws with holes in them. Leave the cups on the pick-up counter in the kitchen.)
-Have each of the children grab a cup of water from the counter and take it back to their seats. Tell them to not drink it yet because we’re going to have a drinking race. (Half the straws should have been pin-pricked a few times so that they have holes in them, but do not mention this.)
-At the signal, have everyone begin. After a minute, ask if anyone had difficulty with their straws.
-Explain what just happened by saying something like the following: Ask, “Have you ever wondered how a straw works?” It is not your great sucking power that causes liquids to come up through your straw to your mouth. Some of you were sucking really hard, but it wasn’t doing you much good, was it? When you sip on a straw, you lower the air pressure inside the straw. As a result, the outside air pressure, which is greater, pushes down on the surface of the liquid, forcing it to move up the straw. When some of you sipped on the straw with the holes, however, the air pressure was pulled directly inside via the holes. The pressure did not exert itself on the water, so the water did not rise up your straw.
YOU WILL NEED: 25 cups full of water, 12 straws, & 13 straws that have holes poked in them (Use a straight pin to poke about 10 holes in each of those straws. Make sure the holes are toward the top, middle, and bottom. Don’t let your children know you are doing this!)
Air Exerts Pressure: Turning Over a Glass of Water
9. Fill a glass with water and cover it with an index card. Ask the children to hypothesize what they think will happen if you flip over the glass. (Flip it over a plastic container just in case this does not work.)
-Explain that the water does not spill out because the air pressure is pushing against the index card.
-Pass out an index card to each child. Allow for the children to take turns trying this. They can scoop up water from their water container, dry off the rim of the glass, place the index card over the top of the glass, and then flip the glass over, making sure it is over the container of water.
-Tell the children that this shows how air exerts pressure.
YOU WILL NEED: 26 index cards, drinking glasses, containers of water, and towels
Egg in a Bottle
10. Explain that air expands and contracts. Most substances expand or spread out when heated and the contract or pull together when cooled. Air does this as well.
-Give each group a bottle and a peeled hard-boiled egg that has been sitting in a bowl of water. Ask them how they think they can get the egg in the bottle without touching or pushing the egg.
-Have one child hold the egg and tell them to set it on the bottle when you tell them to.
-Have parents assist you in setting a rolled piece of paper on fire and then dropping them in the bottles. Set it quickly upright inside the bottle. When the fire goes out and a small stream of smoke ascends out of the bottle, have the child quickly place the egg on the mouth of the bottle. Wait a minute. The egg should get sucked in. (If this doesn’t work the first time, drop a lit match inside the bottle and try again.)
-Go to the next group and repeat until all the groups have an egg in their bottle.
-Ask the children why they think this happened. Let children guess.
-When the fire goes in the bottle, it heats up the air inside the bottle. When the air is heated, it expands and goes out of the bottle. You will see the egg bounce for a moment or two as the heated air escapes around it.
-Ask, “When the fire goes out, what happens to the hot air?” It cools off and shrinks, or contracts. As it contracts, it leaves a partial vacuum inside. The outside air that was pushed out earlier then pushes the egg into the bottle as it tries to get back inside.
YOU WILL NEED: 10 peeled, hard-boiled eggs (Make sure they are completely smooth and have no nicks or that part will get caught on the edge of the bottle. Before doing the activity, place the peeled eggs in water so that they are slippery. Having the eggs be a bit damp allows them to slip into the bottle more easily.), 9 pieces of rolled up paper that is about the size of a post-it note square, at least 20 matches, & bottles (Starbucks frappuccino glass bottles work the best but hard plastic bottles like Oceanspray cranberry juice will also work)
Getting the Egg Out
11. (Prep: Boil a big pot of water. Pour the hot water into 4 bowls.)
-Ask the children how they think they can get the egg out of the bottle. Wait for suggestions. Let them first experiment a minute or two to try to figure out how to do this.
-If no one can figure it out, tell them to just reverse the situation. Instead of creating a vacuum inside the bottle (which brought the egg inside), place pressure inside the bottle to force the egg out.
-Some books suggest that all you have to do is blow into the bottle, hold it upside down, and the egg will come out. Try it. (We’ve never gotten that to work.)
- Bring over the bowls of hot water. Tell the children the water is very hot, so they should not touch it. Let each group share with the group next to them.
-Remind them of what happened to the balloon that was over the 2 Liter bottle when it was placed in hot water. Hold the bottle upside down so that the egg gets lodged in the neck of the bottle. Then place the bottle right side up in a bowl of very hot water (just like we did with the 2L bottle that had a balloon on top). The egg will slowly rise up as the air in the bottle heated up.
YOU WILL NEED: pot to boil water, 4 bowls or containers that can hold hot water that would be large enough to hold the bottom of a 2L bottle, & 4 hot pads
Air Pressure & Water Rising
12. Give each group 1 egg carton or Styrofoam tray, a ball of clay (or 4 candle holders), 4 candles, and 1 drinking glass. Have them place the ball of clay/play-doh on the tray (or the candle holder in the tray) and then place a candle in the clay/candle holder.
-Have them use the drinking glass to get water from the plastic water tub and fill the tray with about 2 inches of water.
-Have the parents help you to light the candle for each group and then have one of the children place an inverted glass over it. Ask, “What happens?” (Probably not much.)
-Repeat the activity, but this time use 4 candles. Ask, “What happens?” (The water should rise when the 4 candles are placed under the jar.)
-Ask the children why they think this happened. Let some children share their ideas.
-Explain: Air expands when heated and contracts when cooled. The candle flame heats the air inside the glass, forcing it to bubble out. If you listened carefully, you could have heard it bubble out during the first few seconds after the glass is inverted. It happens so fast, however, that many people aren’t aware that it’s happening. Later, after the fire goes out, the air inside the bottle contracts and creates a partial vacuum. The air from the outside tries to get back inside. Since it cannot get in directly, the air pushes the water into the bottle to replace the air that was originally pushed out. Basically, the greater the heat, the greater the expansion of air, and the greater the amount of air pushed out of the glass. Then, when the fire goes out, you will have a greater influx of water into the glass.
YOU WILL NEED: 24 birthday candles, 24 pea-sized balls of clay or play-doh and/or 24 plastic birthday candle holders, & items brought by families: lid of egg cartons or Styrofoam trays, glass, lighter/matches, and containers of water
Bernoulli & a Straw Atomizer
13. (Prep: Fill 24 cups about 3/4 of the way up with water.)
-Tell the children that a man named Bernoulli (have them repeat the name “Bernoulli”) discovered that the faster that air moves, the less pressure it exerts, and he discovered that air moves from greater pressure to lesser pressure. We will now demonstrate this.
-Give each child a 2.5″ and a 4″ piece of straw and a cup that is ¾ full of water. Have them hold the 4″ piece of straw in the water with one hand. Have them hold the 2.5″ piece in their mouths. Tell them to blow across the open end of the other straw that is in the water. It works best if one straw is touching the other straw. They should hear a whistle and start a spray of water. If they blow short strong puffs, it will keep it spraying. They should be able to spray water on the person sitting across from them.
-Ask the children, “Can you blow away the liquid or does a good blow bring liquid into your puffs? Why do you think this is happening?” Allow them to share their ideas.
-Explain that this shows how static room pressure pushes into a moving column of air. The column of air is located at the top of the upright straw, so static room air pressure pushes the water up into the moving air column. When it reaches the air stream, the water is “atomized,” which means it is broken up into tiny droplets.
-This is kind of the way sprayers and atomizers work. [Demonstrate your atomizer or pump spray bottle spraying out a liquid, and then open the bottle to show the straw.] Thin straws will often give better results than larger straws because you can get higher air speeds with them.
YOU WILL NEED: 25 pieces of straw cut to about 2.5″, 25 pieces of straw cut to about 4″, 25 small, disposable cups filled ¾ of the way with water, and an atomizer or any container that has a pump spray
Bernoulli & the Beach Ball
14. Use a reverse-flow vacuum cleaner (like a shop vac) to further demonstrate Bernoulli’s Principle. Let the children take turns keeping the beach ball in the air as they hold the hose of a vacuum cleaner hose while it is in the reverse-flow mode.
-Explain that the air column is so strong that a beach ball will be held in the air above the outlet of air. The ball is trapped inside the moving air column. The direct pressure of the air pushes the ball up, which is expected.
-Ask, “Why doesn’t the ball go off to the side and fall down?”
-Explain that the column of air, having low internal pressure, is surrounded by the higher pressure of the static air in the room. The static air forms a “wall” around the moving column, keeping the ball from escaping.
YOU WILL NEED: reverse-flow vacuum cleaner (like a shop vac) and beach ball
Streamlined for Speed
15. Divide children into pairs. They should sit facing each other. Sanitize children’s hands. Give each pair a candle that is set in a candle holder that is set in play-dough or clay. Have other parents help to light the candles.
-Have child #1 hold the flat side of an apple a few inches in front of the flame and then blow directly into the apple. Have child #2 tell them what happened to the flame.
-Relight the candle if needed. Have child # 1 then turn the apple so that the flat, cut side is facing them. Make sure they line up the apple so that the curved side is between them and the candle. Have them try to blow out the candle. Have child #2 tell them what now happens to the flame. Relight the flame if needed.
-Reverse rolls and let child #2 try to blow out the flame and child #1 make the observations. (They can eat their apples as you discuss what happened.)
-Why do they think this is happening? Allow children to share their ideas. Since it is important for an airplane to travel fast, it is clear that planes need powerful engines that develop great thrust. What is not quite clear is the need to reduce drag on a plane, or the force that tends to hold it back. At the high speeds attained by aircraft, drag is a far more serious problem that it is at lower speeds involved in car travel. As a result, aircraft engineers are constantly testing surfaces, shapes, and designs to reduce drag. When you blew on the flat side of the apple, air goes around it and actually turns back, moving toward the person who is blowing. With some practice the candle flame can actually be blown out that way. When using the curved side of the apple, however, the air goes around it and continues on its way. The candle flame moves in the same direction as the original air. Blunt shapes cause drag in 2 ways: by resistance to air as the object moves and by the suction and turbulence of the air behind it.
YOU WILL NEED: 13 birthday candles (can be the same ones used in the earlier activity), 13 plastic birthday candle holders (optional), 13 small balls of clay or play-dough, 13 apples cut in half, lighter/matches, & hand sanitizer
Four Forces of Flight
16. Today we’ve learned some amazing things about air. One of the most remarkable things to consider is how air allows huge, heavy planes to fly through the skies. Bernoulli’s Principles give us some ideas on what allows an airplane to fly. In order to understand how airplanes fly, you need to understand the 4 forces that are acting on the plane at all times.
-An aircraft in straight and level flight is acted upon by four forces: lift, gravity, thrust, and drag. The opposing forces balance each other; lift equals gravity and thrust equals drag. Any inequality between thrust and drag, while maintaining straight and level flight, will result in acceleration or deceleration until the two forces again become balanced. \
-Verbally define the words below. Have the children repeat each term after you and then have the children act out each of the forces. Review them a few times:
Lift: The upward force that is created by the movement of air above and below a wing. Air flows faster above the wing and slower below the wing, creating a difference in pressure that tends to keep an airplane flying.[Have children raise up their arms and say, "lift."]
Gravity: The force that pulls all objects towards the earth. [Have children lower their arms and say, "gravity."]
Thrust: The force that moves a plane forward through the air. Thrust is created by a propeller or a jet engine. [Have children push their arms forward and say, "thrust."]
Drag: The air resistance that tends to slow the forward movement of an airplane. [Have children pull their arms back and say, "drag."]
-Tell the children that next week we will apply these four forces to flight.
17. Review what children learned about air pressure and aeronautics by asking questions such as: What is something you learned about air today? [Allow many children to answer this.] (Air is a real substance, takes up space, exerts pressure, etc.). Who discovered some principles about air and air pressure that relate to the way planes can fly? (Bernoulli) Can anyone name one of his principles/ideas about how air moves? (the faster that air moves, the less pressure it exerts & air moves from greater pressure to lesser pressure) Name one of the forces of flight. [Ask 4 children to each name one.] (Lift, gravity, thrust, & drag) What was your favorite activity from today?
Many of these experiments and explanations came from this book. It has great hands-on activities and explanations that can be understood by children.
Ready for the next lesson?
Build an aluminum foil barge that can hold the most pennies, experiment with what floats and sinks and why, create working models of various ships and a submarine, design and build a variety of airplane and parachute models, and more during this 5 part hands-on unit study on floating and flying.
- Buoyancy and Floating Lesson Plan - This is part 1 of a 5 part hands-on unit study on Floating & Flying (Fluid Mechanics). This week's focus is buoyancy (floating). Build an aluminum foil barge that can hold the most pennies, experiment with what floats and sinks and why, explore the relationship between density and buoyancy, and more!
- Floating Ships and Boats Lesson - This is part 2 of a 5 part hands-on unit study on Floating & Flying (Fluid Mechanics). This week's focus is ships and boats. Create working models of sailboats, submarines, and hovercrafts, test out jet power, examine the impact of density of liquids and surface tension on floating, and more!
- Air Pressure and Aeronautics Lesson - This is part 3 of a 5 part hands-on unit study on Floating & Flying. Discover the properties and power of air as you watch as air pressure blows up a balloon, sucks an egg into a bottle, collapses a can, holds water in an upside-down glass, and more!
- History and Forces of Flight Lesson - This is part 4 of a 5 part hands-on unit study on Floating & Flying. Learn about the history of flight from the time of the Greeks through present day. Design and redesign foam fliers, balloon jets, parachutes, drag-chutes, and more as you examine the four forces of flight!
- Paper Airplanes & The Four Forces of Flight Lesson - This is part 5 of a 5 part hands-on unit on Floating & Flying. Have fun while creating various types of paper airplanes in order to examine the relationship between plane design and the four forces of flight!
- Floating and Flying Unit Presentations and Field Trip Ideas – This is the culminating activity for the five part hands-on unit on Floating & Flying. The children made ship and plane-themed dishes (recipes are included) and presented on famous planes or ships. Also included is where we went for field trips during this unit.
Video clips on air and air pressure we enjoyed -- Also look for Bill Nye's video on flight!
Would you be able to explain how airplanes fly in the sky?
Would you like to teach this way every day?
I use Konos Curriculum as a springboard from which to plan my lessons. It's a wonderful Christian curriculum and was created by moms with active children!
If you're new to homeschooling or in need of some fresh guidance, I highly recommend Konos' HomeSchoolMentor.com program! Watch videos on-line of what to do each day and how to teach it in this great hands-on format!
© 2011 Shannon