Daily Warm-Up Exercises Day 5 You fill a syringe with 30 cc of air. You seal the end and push the plunger. The plunger moves. What does this show about air? It is compressible (it can be squeezed into a smaller space). You push the plunger as hard as you can. It goes to 10 cc but not any farther. What does this show about air? Why is air compressible? because it’s a gas, and gases contain a lot of empty space What will happen when you let go of the plunger? it will move back out Why? The air pressure inside the syringe is greater than the outside air pressure. The air molecules inside the syringe hit the plunger and push it out. What is pressure? a force or set of forces that is spread out over a surface It takes up space. Daily Warm-Up Exercises Daily Warm-Up Exercises 1

Visualization Exercise 2.1 Zoom Visualization Exercise 2.1 >>>next slide<<<

Zoom Exercise 2.1 Image comprehension focus: Zoom Rationale: Diagrams often show magnified images of objects that are normally too small to see. Sometimes the degree of magnification is explicitly indicated, but often the change in scale is vague. Students may understand that the image is not drawn to scale, but not fully realize just how drastic the difference really is. This image shows air particles as visible dots, but does not directly address the fact that gas molecules are extremely small. This kind of image is fairly common with images that show particles of matter, but is also frequently used to display other kinds of objects that would otherwise be invisible. Though this can be very useful, it can also create confusion as to the actual size of what is being diagrammed. One added problem that students often have with understanding matter as particles has to do with what those particles are moving through. Students often mistakenly believe that particles are floating around in a substrate, when in fact they are moving through empty space. Diagrams like this one can feed this inaccuracy, since it looks like the particles are floating around in the air - when in fact the particles are the air. Type of Activity: Teacher Comment Objective: To introduce the use of Zoom in diagrams, especially with regard to the particle model of matter Module Images: CD-Rom Procedure: Explain: “Here we are shown two images of the same syringe. On the left, it is shown before the plunger is depressed, and on the right it is shown after the plunger is depressed. Note the small blue circles in each of the pictures: they are meant to represent particles of air trapped within the syringe. We probably know that particles of air are much, much smaller than they are shown in this diagram, but because they are so small that they’d be invisible to us, the artist who created this diagram chose to enlarge them so that we can see what is happening. It is very important to carefully think about the true size of the objects in diagrams, and to recognize when the author is changing that true size in the diagram. If we do not do this, we can easily get confused about what the diagram means. The purpose of this diagram is to explain that, even when the air is compressed, the number of particles in the syringe stays the same. This is accomplished visually by making the ‘air particles’ so large that we can actually count them. The blue circles, as shown in this diagram, are meant to stand for air particles so that we may understand that there is a specific amount of air in the syringe regardless of whether the plunger is up or down. The number of particles of air in the syringe remains the same even when placed under pressure by depressing the plunger of the syringe. The blue circles that stand for air particles do a good job of visually explaining that when the air is pressurized, the particles move closer together, because they can not leave the space within syringe.” Explain: “This image does a good job of showing what happens to the particles in some compressed air – BUT a reader might get the wrong idea about the true size of air particles. Sometimes, if an author wants to avoid this kind of confusion, they will use a convention called a “zoom.” >>>next slide<<<

Zoom Procedure: Explain: “This is what the diagram would look like if the author used a zoom instead of simply drawing the particles as large blue circles. In this case, you can imagine that the circle shows what we would see if we were able to view the air in the syringe with an extremely strong microscope.” Ask: “Why does it look like there are more air particles in the right-hand zoom?” Explain (If needed): “The air particles in the syringe on the right would be more-closely arranged than those in the left—so when we view these through a microscope, there will be more particles packed into the small area that we are looking at. Remember though - there are the same total number of particles in both syringes.” Explain: “There is one more very important thing to think about when we look at a diagram like this. The ‘particles’ that are shown in the image appear to be floating in some ‘stuff’, but they are not. It is not like specks of dust floating through the air. When we are talking about particles, we are talking about things that are much smaller than specks of dust. If you think about it, it does not make sense to think about air particles floating through the air – since the air particles are the air. It is hard to imagine this, but there is nothing in between these particles – they are moving through empty space. >>>next slide<<<

Zoom and Use of Color Procedure: Explain: “As a way of reminding the reader that particles are surrounded by empty space, we could draw the zooms like this. In reality, empty space does not really have a color, we are just choosing black because we often think of empty space as being black. In other words, we could choose any color we want to stand for empty space, but are choosing black because it might make it easier for the reader. During this unit, you will sometimes see zooms with a black background – when you see this, you should remember that it stands for empty space, and is there to remind you that particles are surrounded by empty space.” >>>end of exercise<<<

Air Has Mass Investigation 2, Part 1b Where's the Air?

Mass Mass is the amount of matter in an object. We can compare the mass of two objects by placing them on a balance. We will learn more about mass in Investigation 5. Daily Warm-Up Exercises 7

Does Air Have Mass? Do you think air has mass? (answers will vary) Can you think of an experiment you could do to find out if air has mass? (answers will vary) Your teacher will do an experiment that will show whether or not air has mass. Daily Warm-Up Exercises 8

Analyze the Results When we blow up a balloon, how does the air inside the balloon compare with the air outside the balloon? The air inside the balloon is compressed. There are more air molecules inside the balloon than in an equal volume of air outside the balloon. Daily Warm-Up Exercises 9

Analyze the Results What happens when both balloons are full? They balance. What does that show? They have the same mass. What happens when one balloon is empty? The side with the full balloon goes down. What does that show? The full balloon has more mass than the empty balloon, so air has mass. Daily Warm-Up Exercises 10

Reading Turn to page 6 in your Resources book. Read What's in the Air. Daily Warm-Up Exercises 11

Visualization Exercise 2.2 Reading a Table Visualization Exercise 2.2 >>>next slide<<<

Resources, P. 6 Exercise 2.2 Image comprehension focus: Reading a Table Rationale: Tables are an effective and often-used method of organizing and representing data. It is important that students are able to recognize the structure and function of data tables in order to effectively utilize the data content of the table. Type of Activity: Teacher Comment Objective: To introduce the use of data tables as information organizers. Module Images: Resources, P. 6 Procedure: This exercise is designed to reinforce some basic table-reading skills. Explain: “This is a table. Using a table is an effective way to organize data. This is a pretty basic table, so it’s a great place to start learning how to read information shown in this way.” Explain: “Many tables have titles that tell you what the table is about. In this case, we are told in the table title that the data contained in the table will describe permanent gases of the atmosphere.” Explain: “Beneath the table title we find the column headings. In this case, they explain that there are two columns: one will contain the names of gases, one will contain the percentages in the atmosphere of those gases.” Explain: “The lines of boxes that run horizontally left to right are called rows. To get the information that the table is trying to give us, we read across these rows. So, if we want to see the percentage of argon, we read down the column labeled ‘gas’ to find argon. From there we read across the row to find that argon composes .93% of the atmosphere. Ask: “What percentage of the atmosphere does oxygen compose?” [20.95%] Explain: “I’m sure you have figured out that you can do this in reverse as well.” Ask: “By reading down the ‘percentage by volume’ column, tell me which gas composes 78.08% of our atmosphere? [nitrogen] Ask: “According to this table, which permanent gas composes the smallest percentage of our atmosphere?” [xenon] >>>end of exercise<<<