Factors of Weather- Under Pressure!
Lesson 2 of 8
Objective: Students will conduct an experiment to demonstrate how air pressure and humidity work.
I rang my chime to get the class’s attention. I announced that we were about to begin the next Science lesson in our unit about weather. I asked them to return to the carpet squares and ‘Show Five’.
Once seated, I started a short, yet significant, activity so the students could experience this concept first hand. “Put you hand in front of your face. Put your lip together and blow. What do you notice?” “I felt the air on my hand.” “Now open your mouth. Blow again. It’s a little harder when your mouth is open so pull your stomach in fast to force out some air. What did you feel now? Was this different?” “I felt wet air on my hand.” “Take a short time to talk to the person next to you and share your ideas.” I give them 5-10 seconds to explore this idea with a partner before I get their attention with the ring of our chime.
Whole Group Instruction
“How many of you have heard about ‘weather’?” As many students raise their hand, I added “The cool thing is weather doesn’t exist as a whole. It’s a sum of its parts.” For explanation, I added, “That means it’s made up of many pieces. Who can think of something that is a part of weather?” “Air..wind..sun…” I was happy to see the students access the vocabulary from prior lessons. As each contribution is made, I add it to a list that will become the basis of subsequent lessons, including some color coding to help retention. "The thing all these things have in common- something that connects them all like a puzzle- is that they are all affected by the atmosphere. Remember, atmosphere is made up of the air that surrounds the Earth. This air is made up of gasses- not the kind of gas you put into a car though. We can’t see this kind of gas. It exists to makes sure living things can survive in ways that are right to them.”
As with most lessons (I'm a very physical teacher and move all the time!), I use a globe and my hands to demonstrate my words, “Air is heaviest the closer it gets to the earth’s surface. The heavy air presses other air down, and that pressure is what causes the warm and cold air to either stay in one place or move around. Warm air comes from the south and cold air comes form the north so depending on where the air comes from, it makes the area either warm or cold. This combines with moisture in the air to create conditions unique to that area called climate. This climate determines what plants and animals can survive in that place. You’re all going to take a minute to go to your tables to practice an example of how air pressure works to keep things in one place, which creates different climates.”
• Paper, 8 1/2 x 11"
• Ruler, 1' (one per group)
• Spray bottle of water
After the whole class instruction finished, I used the chime to dismiss the students by groups back to the tables. I explained, “There’s a very simple demonstration that we’re going to conduct. Just like real scientists do, we’ll share our discoveries with others around us. This spreads our discoveries so more people learned what we learned.” I always want to bring ideas back to the ideal of a scientific community where ideas are shared and knowledge is spread. “The demonstration will show you how air pressure pushes down to make a piece of paper stay in one place. We’ll add some water to demonstrate how humidity makes the air even heavier so the paper doesn’t easily move. Demonstrations like this represent conditions that exist in our environment. It’s easier to understand something when we can see it, right? It not so much that paper moving is important, more the concept it demonstrates.” It’s important to me that I treat students as scientists so I use as scientifically accurate vocabulary as possible, ‘translating’ or rephrasing when appropriate.
I chose this particular demonstration because it provides a way to test the concept simply, with few materials. This makes it easy- both for us implement and others to replicate. “All we need for this demonstration is our table, a piece of paper, ruler, and water bottle. Any questions or comments?” “Noooo….” “The first thing that we’ll do is put the ruler on the table and leave about a hand’s distance hanging over the edge.” I show them how to measure this and continue. “Then, we carefully lay the paper over the ruler so it’s equal- same- distance from the sides. That means it’s centered.” While Math terms like this may be confusing, I like to use them to expose the students to the terms in actions, giving as many demonstrations and explanations of them as necessary. “Once you’ve done this, start to experiment with pressure as you press down on the end of the rule that is hanging over the table edge. Start with one finger, then two. Use your hand. Talk to each other as you take turns and describe what you feel. Share what happens to the paper. This is the process that scientists follow when they do experiments.”
I circulated among the students as they completed this assignment to spend adequate time listening to their comments (“The ruler feels like it’s really heavy.” “I’m gonna press down more.”) and ask for clarification (“Tell me more about that.”) when necessary. While I don't see any 'dramatic' demonstrations of air pressure, I do see a group of engaged students who never stop looking for them. That- to be honest- is a learning product that exceeds my expectations. After they complete the first step, I spray some water above their paper to show how humidity settles on paper to add weight. I give them a minute to finish their discussion about their observations before I signal an end to the lesson.
After the demonstration was completed, I use a chime to single the end of this lesson piece. I ask the Daily Helpers to collect the rulers and wet papers so they could be put or thrown away. I ask the remaining students to “blow” themselves back to their carpet squares. Any time a teacher can connect the lesson concept to a simple activity like returning to their seats, it makes the learning process much more fun, along with acting as a physical reminder of the material that was covered.
To act as a whole class recap, we gather again to share out the results of the demonstration, (“Our paper was hard to pull up.” “The air pressure made the paper stay on the table”. “Water made it way heavier.”). While this was a complex concept for Kindergarten, I feel the students got enough out of it to apply it to future lessons. The ultimate goal is to combine some recent design thinking lessons to this material and encourage the students to see a problem and find a way to solve it. It will be interesting to see if the students connect this demonstration to other, more common, experiences. I can’t wait to see!