Lighter than air flight and more properties of air - Lesson 2

Review of Notes and vocabulary = Fun

We reviewed our vocabulary words by playing Four Corners.  The students had 5 seconds to pick a corner.  I would pick the corner with the most students and ask them to tell me the vocabulary word to the definition I called out.

Manna moment-Air

Romans 1:20- "For His invisible attributes, namely, His eternal power and divine nature, have been clearly perceived, ever since the creation of the world, in the things that have been made.  So they are without excuse."

There are some people in the world who struggle with the idea of an invisible, omnipresent God.  They think that since they cannot see God with their physical eyes, He must not exist.  Whether they understand it or not, they believe that only what they can physically see must be real.  

Do you struggle with believing in a God you cannot see with your physical eyes?  This week we are continuing to learn new things about air- something that is invisible and yet all around us.  Jesus, our Emmanuel, is invisible to us now yet all around us too.  Often Jesus would use parables rooted in our physical world to help us understand a spiritual truth.  
Romans 1:20 reminds us that God made sure that man would have no excuse not to believe in Him because He has demonstrated His eternal power and divine nature through creation.

Properties of Air

1.  Air Takes Up Space AND Exerts a Force

Using a grocery bag, wide-mouthed jar, and a rubber band, we wanted to see air pressure exert a force on the grocery bag and see how air takes up space in this demonstration.

We pushed the empty grocery bag into a wide mouth jar leaving the edges hangin over the sides.  Using a rubber band, we tied the sides of the grocery bag hanging off the side to secure the bag.  Carefully, we attempted to pull the bag out of the jar.
We could not easily pull the bag out of the jar because of the pull force from air pressure.  A vacuum was created between the jar and the bag where no air could fill the space and allow the bag to be removed from the jar.  However, once the air, which takes up space, was allowed between the bag and the jar, the bag was released and easily removed from the jar.

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2.  Air Has Mass and Exerts a Force

For this demonstration, we used a ruler, table and newspaper.  We set the ruler on the edge of a table or desk with a part of the ruler hanging off the table.  We placed a large piece of newspaper across the ruler resting on the table.  Then applying some pressure to the ruler hanging off the table, attempted to move the ruler up.  

Air has mass and therefore exerts a push force.  The air on top of the paper is resisting moving which pushes it down and prevents the ruler from flipping off the table.

3.  Air Pressure Can Be Put to Work

Using straws, you can demonstrate how air pressure can exert a pull force when the top of the straw is covered.  Placing a straw in a cup of water, covering the top of the straw with your finger, you created a vacuum.  The air, by covering the top of the straw, was cut off allowing the air pressure to pull the water up the straw.  Once you release your finger, the vacuum was broken and gravity pulled the water down and out of the straw and back into the cup.

I changed things in class by having the students use pipettes.  This did not create the system as you would with a straw on account of the pipette not being open on the top.  What is the difference between using a pipette versus a straw?

Hot air balloon investigation

Guiding Question:  Which plastic bag will climb the highest when you fill it with hot air?

We used regular grocery plastic bag and then a bigger kitchen trash bag.  I wrapped the plastic bag around the mouth of the blow dryer, secured a rubber band, then taped above the rubber band.  Removed this from the blow dryer and cut off the excess handles.
Placing it back on the blow dryer, turn on the blow dryer and fill the bag with hot air.  When full release the bag quickly and document how high it went up.  There is room on this investigation sheet to have three trials and then calculate the average.  This isn't the easiest thing to do but much of what the Wright brothers did to try and accomplish flight was hard.  This is a good practice activity.
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Flying High Work

To learn about Air pressure and Wind, here is a great Study Jams video accompanied by our Video Guide

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