Air Pressure Demonstration

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SWBAT to understand the effects of air pressure changing from high to low.

Big Idea

By observing a teacher-led demonstration, students will visualize high and low air pressure.


5 minutes

Teacher Tip: This lesson is intended for students to understand how air pressure can go from high to low.  Students will observe a demonstration for which you will need the following materials- small balloon filled 3/4 full with water, glass bottle, matches, small strips of paper. To see how the demo works, watch the video in the EXPLORE section of the lesson. Students will make predictions, write observations about the demo, and support it with evidence, thus addressing NGSS SP1, 6 and 7.

To start the lesson, students will independently work to answer the following prompt in their student notes sheet:

ENGAGE: What happens to air pressure as you go higher in altitude? (it decreases)

This question serves as a review from the previous lesson, Air Pressure. After 3-4 minutes, I will ask a student or two to share their responses with the class. 


5 minutes

Students will now make a prediction about what is going to happen with the balloon demonstration.  I show them the materials I will be using and explain to them that I will light the strip of paper and toss it into the bottle, covering the opening with the water balloon.  Students will be guided through their prediction with the following prompt in their notes sheets: 

EXPLORE: Write a prediction about the balloon demo based on your prior knowledge.

I think the balloon will…


Students often predict the balloon will pop because they generally don't know what else could happen. Some suggest the balloon will get "sucked" into the bottle.  After 3-4 minutes, ask 3-4 students to share their predictions and record them on the board for others to see. 


10 minutes

Now, I perform the demonstration.  Students get very excited during the demo as there is fire and they are expecting a loud popping sound because they think the balloon will pop.  Remind them they are responsible for recording observations during this time and they should be acting like mature scientists.

Preview the questions in the notes sheet for recording observations prior to performing the demonstration so that students have a chance to realize what they are looking for: 

EXPLAIN: Write down what you observed during the demo.

I saw...

Remind them to be thorough in their observation. What happened exactly, step-by-step.  

Air Pressure Demonstration


10 minutes

Next, students take what they've observed in the demo and apply it to what they already know about air pressure. They make an inference about what happened by answering the following prompt in their notes sheets: 

ELABORATE: Make an inference about what you observed using your knowledge of air pressure.

I observed…

I think this happened because…

Students will say the balloon got "sucked" in. Remind them that their is more air pressure on top of the balloon than underneath.  This generally allows them to see that the balloon must have gotten pushed in, instead. 


5 minutes

Next, students will independently work to reflect on the task for the day by responding to the following: 

EVALUATE: Finish the sentences below.

When air pressure is high… (air particles are closer together and have less space to move)

When air pressure is low…(air particles are further apart and have more space to move) 

For a sample student response, check out EVALUATE student sample.