PREDICT-OBSERVE-EXPLAIN: AIR AND AERODYNAMICS
"Students explore the characteristics of air and the interaction between moving air and solids. They learn that air is a compressible fluid, that it is composed of many gases, and that moving air can support solid materials in sustained flight. By studying birds and airplanes, they learn a variety of adaptations and designs that make flight possible and that provide for propulsion and control" (Alberta Education, 1996).
GENERAL OUTCOME:
6–5 Describe properties of air and the interactions of air with objects in flight.
SPECIFIC OUTCOME:
- Students can provide evidence that air takes up space and exerts pressure, and identify examples of these properties in everyday applications (Alberta Education, 1996).
- Students can describe and demonstrate instances in which air movement across a surface results in lift— Bernoulli’s principle (Alberta Education, 1996)
TASK:
Students will apply Bernoulli's principle from the experimental setup to a new situation (how airplanes fly).
GENERAL OUTCOME:
6–5 Describe properties of air and the interactions of air with objects in flight.
SPECIFIC OUTCOME:
- Students can provide evidence that air takes up space and exerts pressure, and identify examples of these properties in everyday applications (Alberta Education, 1996).
- Students can describe and demonstrate instances in which air movement across a surface results in lift— Bernoulli’s principle (Alberta Education, 1996)
TASK:
Students will apply Bernoulli's principle from the experimental setup to a new situation (how airplanes fly).
MATERIALS:
- 2 pieces of string of equal length - 2 balloons - 2 chairs - Rod - Hairdryer - Electric outlet |
- Whiteboard or Smartboard
- Dry Erase markers - Masking tape - Pens and pencils - Worksheets (See below)
|
LESSON PLAN
INITIAL SET UP:
With masking tape and markers, mark out three squares on the floor. Each square represents a different state of solid, liquid and gas. The first square should be large enough to fit all your students in a very cramped fashion with no space to move. The second square should be large enough to allow for minimal shuffling around. The last square should be large enough for students to dance around. Blow up both balloons prior to the lesson. Tie a string to the end of each balloon. *After the students have guessed what the experiment will be, have them watch you set up the rest. Place the rod between the two chairs near an electrical outlet, with the rod sitting on top of the backrest of each chair so that there will be room for the balloons to hang freely between the chairs. Tie each balloon to opposite ends of the rod using the string (they should be at least a foot apart, unlike the image below). Plug in the hairdryer.
STRATEGIES:
PROCEDURE:
Kids are sitting down at the desk with the worksheet in front of them so they can look at the questions. This is important so that they are not distracted by the setup of the experiment (balloons) while each student takes turn talking during discussion. Cue students to be respectful when others are speaking.
1. Connect:
- Explore what students know about the properties of air by asking about their experiences:
With masking tape and markers, mark out three squares on the floor. Each square represents a different state of solid, liquid and gas. The first square should be large enough to fit all your students in a very cramped fashion with no space to move. The second square should be large enough to allow for minimal shuffling around. The last square should be large enough for students to dance around. Blow up both balloons prior to the lesson. Tie a string to the end of each balloon. *After the students have guessed what the experiment will be, have them watch you set up the rest. Place the rod between the two chairs near an electrical outlet, with the rod sitting on top of the backrest of each chair so that there will be room for the balloons to hang freely between the chairs. Tie each balloon to opposite ends of the rod using the string (they should be at least a foot apart, unlike the image below). Plug in the hairdryer.
STRATEGIES:
- Formulate questions that will allow students to critically reflect on the lesson. Students should be doing most of the talking, while the teacher acts as a facilitator and guide.
- Tap into prior knowledge of students at the onset of the lesson to gauge the direction of the lesson.
- At the end of the lesson, provide opportunities for students to apply the knowledge to a new situation.
- Differentiate the instruction by providing many different ways to access the information; auditory (teacher talking), visually (white board drawings), tactile (experiment), kinesthetic (physical demo), and oral (discussion).
PROCEDURE:
Kids are sitting down at the desk with the worksheet in front of them so they can look at the questions. This is important so that they are not distracted by the setup of the experiment (balloons) while each student takes turn talking during discussion. Cue students to be respectful when others are speaking.
1. Connect:
- Explore what students know about the properties of air by asking about their experiences:
- Can you remember a time when you played with a balloon? (At a birthday party?)
- Why does it float? (*Helium: It floats because it is lighter than air. It is the second lightest element. The lightest element is hydrogen.)
- What is air made of? (Different elements like oxygen and methane?)
- When you blow up a balloon, why doesn’t it deflate after you tie it off? (Why is the pressure greater inside the balloon than outside it?)
- Have they ever done experiments with balloons before? (If so, what was the topic at hand? What did you learn?)
- Show students all the materials of the set up. What do they think the task will be? (Looking at all the materials, what do you think we will do today?)
- Introduce the question: *With only a hairdryer, how would you make the two balloons touch each others consistently for more than three counts?
(How would you aim the air current?) - Students make predictions and share them orally in turn. Then they write them down on the worksheet.
- Students then draw the set up in one box on the handout and draw their prediction in the other box
- They take turns leaving their seat and testing their predictions according to who finished drawing first,
- When they finish, they return to their seats
- Students then record their observations of what actually happened and share their explanations in turn.
- Teachers introduce a new question:
*What do you think will happen if we blow air between the two balloons?
- Have students record their oral responses on the worksheet provided
- Have students record their oral responses on the worksheet provided
2. Predict:
Teachers explain the experiment and get the students to predict what will happen both verbally and in written form. We envision, like ourselves, students will hold the misconception that the balloon will move in the direction it is being blown. Students are already curious from their previous mini-POE.
3. Observe: Teachers demonstrate the experiment before allowing students to repeat/do it themselves.
Discrepant Event: The two balloons will pull together when air is blown between them. Why is that???
4. Explanation:
Teachers will encourage the students to try and tentatively explain what happened in the experiment they just observed and tried for themselves. After the discussion, present and introduce Bernoulli’s principle:
The teacher can also show how just one balloon will be attracted to the lower pressure area created by the high speed of the hairdryer. Have one student hold one of the balloons on a string and the teacher will turn on the hair dryer a foot away. The balloon should move toward the air current, and would fly along it if the student let go of the string.
Teachers explain the experiment and get the students to predict what will happen both verbally and in written form. We envision, like ourselves, students will hold the misconception that the balloon will move in the direction it is being blown. Students are already curious from their previous mini-POE.
3. Observe: Teachers demonstrate the experiment before allowing students to repeat/do it themselves.
Discrepant Event: The two balloons will pull together when air is blown between them. Why is that???
4. Explanation:
Teachers will encourage the students to try and tentatively explain what happened in the experiment they just observed and tried for themselves. After the discussion, present and introduce Bernoulli’s principle:
- Explain: Everything in the universe is made up of particles. These particles exist in three types of states: solid, liquid and gas.
The teacher can also show how just one balloon will be attracted to the lower pressure area created by the high speed of the hairdryer. Have one student hold one of the balloons on a string and the teacher will turn on the hair dryer a foot away. The balloon should move toward the air current, and would fly along it if the student let go of the string.
BERNOULLI’S PRINCIPLE → High Speed = Low Pressure, (HOW AIRPLANES FLY)
In any fluid (air and liquid), an increase in velocity results in a decrease in pressure. There is an opposite effect on speed and pressure, when one goes up the other comes down. The wing of an airplane is shaped so that the top of the wing is curved and the bottom of the wing is straight. The difference in shape at the top of the wing and the bottom of the wing causes the air to travel at different speed. Where do you think the air is traveling faster? (Answer: at the top). The object or wing will be drawn to go to the lower pressure area, hence lifting the wing. How do you think this principle applies to the experience we just saw? When we blow between the cans we create a low pressure area between the cans and the objects or the cans are drawn to the low pressure area and are pulled together.
Teachers promote and facilitate discussion to explore what students understand about this topic.
In case a student requires visuals to understand, there will be a whiteboard or Smartboard available to provide space to draw diagrams, as well as a laptop or iPad or image at hand to aid the audio description: http://library.thinkquest.org/2819/bernoull.htm
ASSESSMENT:
Teachers will check for understanding by using the following formative assessment tools: self-assessment, observations, and summative assessment. The students will have an opportunity to reflect on their own learning by completing a handout throughout the lesson. We will observe the student’s learning by gathering evidence from what the students are saying and doing during the lesson. Finally, students will hold up their answer on a whiteboard after being asked questions about the topic as a summative assessment.
EXTENSIONS:
-How does air conditioning (fans) work?
-How does the hairdryer work?
-Have you ever played with a Chinese dragonfly toy? Why does it fly?
http://almostunschoolers.blogspot.ca/2011/05/folk-toy-fridays-hand-propeller.html
-What do you think will happen to birds that are flying too close to an airplane engine?
Chicken Cannon: http://www.apnewsarchive.com/1994/To-Make-A-Jet-Engine-Bird-Carcasses-Get-Rough-Ride/id-4dc509720ebf666cc971783ab8ec5779
In any fluid (air and liquid), an increase in velocity results in a decrease in pressure. There is an opposite effect on speed and pressure, when one goes up the other comes down. The wing of an airplane is shaped so that the top of the wing is curved and the bottom of the wing is straight. The difference in shape at the top of the wing and the bottom of the wing causes the air to travel at different speed. Where do you think the air is traveling faster? (Answer: at the top). The object or wing will be drawn to go to the lower pressure area, hence lifting the wing. How do you think this principle applies to the experience we just saw? When we blow between the cans we create a low pressure area between the cans and the objects or the cans are drawn to the low pressure area and are pulled together.
Teachers promote and facilitate discussion to explore what students understand about this topic.
In case a student requires visuals to understand, there will be a whiteboard or Smartboard available to provide space to draw diagrams, as well as a laptop or iPad or image at hand to aid the audio description: http://library.thinkquest.org/2819/bernoull.htm
ASSESSMENT:
Teachers will check for understanding by using the following formative assessment tools: self-assessment, observations, and summative assessment. The students will have an opportunity to reflect on their own learning by completing a handout throughout the lesson. We will observe the student’s learning by gathering evidence from what the students are saying and doing during the lesson. Finally, students will hold up their answer on a whiteboard after being asked questions about the topic as a summative assessment.
- Various forms of formative and summative assessments were utilized.
- Formative assessments that were used included; discussions, self assessment, fill in the blank with prompt sentences, predicting, explaining, and drawing on the white board.
- Summative assessments that were used included; handout, and applying the principle to a new situation.
- Strategies were effective because they were embedded into the lesson.
EXTENSIONS:
-How does air conditioning (fans) work?
-How does the hairdryer work?
-Have you ever played with a Chinese dragonfly toy? Why does it fly?
http://almostunschoolers.blogspot.ca/2011/05/folk-toy-fridays-hand-propeller.html
-What do you think will happen to birds that are flying too close to an airplane engine?
Chicken Cannon: http://www.apnewsarchive.com/1994/To-Make-A-Jet-Engine-Bird-Carcasses-Get-Rough-Ride/id-4dc509720ebf666cc971783ab8ec5779
REFLECTION:
We were originally going to use two pop cans for the experiment, however we found that not every student (or teacher) has the lung capacity to blow air at the velocity necessary for the experiment to work. Replacing a person blowing through a straw with a hairdryer, we found that the cans looked like they flew away from the blow dryer before coming together. However, the same discrepant event will also work with balloons on a string.
Preparation is key, both having tested the experiment yourself more than once (so that when you demonstrate, you know exactly how close and how to aim the hairdryer to get the discrepant event) and mentally anticipating student responses. Students may have a rough idea from outside sources about the existence of things such as "static/electricity," "magnetism/magnetic currents," "atoms," "molecules," "oxygen," and "photosynthesis," that they cannot see with the naked eye but can see the effects of or with the right equipment. Refrain from correcting students during the initial discussion phase to understand what they already know. Always redirect what they share back to the topic or their explanations back toward explaining the discrepant event and ask clarifying questions. If necessary, go back to the beginning and paraphrase what they say to model how to give a logical explanation step by step so that it can be understood by others.
REFERENCES:
Alberta Education. (1996). Science Elementary. Retrieved from: http://education.alberta.ca/media/654825/elemsci.pdf
Grade 6 Flight Webquest. Retrieved from: http://flightwebquest.blogspot.ca/p/four-forces-bernoullis-principles.html
Shaffer, D., Wood, E., & Willoughby, T. (2002). Developmental Psychology Childhood and Adolescence First Canadian Edition. Ontario: Thomson Nelson
We were originally going to use two pop cans for the experiment, however we found that not every student (or teacher) has the lung capacity to blow air at the velocity necessary for the experiment to work. Replacing a person blowing through a straw with a hairdryer, we found that the cans looked like they flew away from the blow dryer before coming together. However, the same discrepant event will also work with balloons on a string.
Preparation is key, both having tested the experiment yourself more than once (so that when you demonstrate, you know exactly how close and how to aim the hairdryer to get the discrepant event) and mentally anticipating student responses. Students may have a rough idea from outside sources about the existence of things such as "static/electricity," "magnetism/magnetic currents," "atoms," "molecules," "oxygen," and "photosynthesis," that they cannot see with the naked eye but can see the effects of or with the right equipment. Refrain from correcting students during the initial discussion phase to understand what they already know. Always redirect what they share back to the topic or their explanations back toward explaining the discrepant event and ask clarifying questions. If necessary, go back to the beginning and paraphrase what they say to model how to give a logical explanation step by step so that it can be understood by others.
REFERENCES:
Alberta Education. (1996). Science Elementary. Retrieved from: http://education.alberta.ca/media/654825/elemsci.pdf
Grade 6 Flight Webquest. Retrieved from: http://flightwebquest.blogspot.ca/p/four-forces-bernoullis-principles.html
Shaffer, D., Wood, E., & Willoughby, T. (2002). Developmental Psychology Childhood and Adolescence First Canadian Edition. Ontario: Thomson Nelson