Where’s the Air?Where’s the Air?

ObjectivesObjectives

• I can explain if air has mass.

• I can provide evidence to support my claim of if air has mass or not.

Quick WriteQuick Write

•Where does weather happen?

–ATMOSPHERE

AIRAIR• In our first investigation we

used a variety of weather tools to measure weather conditions. Air plays a very important role in the weather. In the next few days we are going to look more closely at air to learn some of its properties.

SYRINGESYRINGE• This is a syringe. You can

use it to investigate air. You can work with your syringe alone or with other students, but you should not use the syringe to annoy another student!

SYRINGESYRINGE• Things that annoy other

students:–Blowing the syringe in their face

–Taking someone elses syringe without asking

MATERIALSMATERIALS• You have the following materials–Syringe–Tubing–Binder clip

SYRINGESYRINGE• See if you can answer these questions:–What happens to the air in the syringe when you push and pull on the plunger?

–What can air do?

33 33

Example: When you push the

plunger down, the air in the

syringe is pushed out the tube.

Example:

Does air have weight?

AIR INVESTIGATION

Observations Questions

Air Observations Discussion Air Observations Discussion QuestionsQuestions

• When you clamp the tube closed and push the plunger down, what happens to the air?–The air is pushed into a smaller

space.• Is there more air, less air, or the

same amount of air in the syringe when the air is pushed into a smaller space?–Same amount

Air Observations Discussion Air Observations Discussion QuestionsQuestions

• What happens when you let go of the plunger after pushing down?–The air pushes the plunger back

up.• What do you think happens to the

air when it is pushed into a smaller space?

• What happens to push the plunger back out when you release the pressure on the plunger?

COMPRESSIONCOMPRESSION• When you push on the

plunger, the air is forced into a smaller space. We say the air is compressed. The same amount of air is still in the syringe when it is compressed.

PRESSUREPRESSURE• Compressed air pushes back

with a force equal to the force compressing it. If the force on the plunger is released, the pressure in the compressed air will push the plunger out. The compressed air pushes back, and the push is called pressure!

What to you think will happen if we put this blue cube into the syringe with the tubing clamped?

What do you think will happen to this pink packing bubble?

GAS IN A SYRINGE

AIRAIR• Everything is made out of atoms and molecules, including air. The molecules in gases are free to move around throughout the volume of gas. There is a lot of space between the molecules in gases.

AIRAIR• When a volume of gas is compressed into a smaller space, the molecules are pushed closer together. The number of molecules is the same; they are just closer together.

AIRAIR• Molecules compressed into a

smaller space bump into one another more often, and this creates pressure. Pressure pushes in all directions, and if the force keeping the gas compressed is reduced, the gas will expand into a larger space and the molecules will get farther apart.

WORD BANK• Compression- When air is forced into

a smaller space.• Pressure- compressed molecules

pushing back with a force equal to the force that compressed it.

QuestionsQuestions• Does air have weight (mass)?• Where does air pressure come

from?• How does air push the syringe

plunger out?• Why is air pressure so strong?

33 33

Example: When you push the

plunger down, the air in the

syringe is pushed out the tube.

Example:

Does air have weight?

AIR INVESTIGATION

Observations Questions

Let’s review our questionsLet’s review our questions

• Review from Friday-

• What happens to air when is it compressed?

• Objectives:

I will design an experiment to prove that air does, or does not, have

mass.

I will provide evidence to support my claim.

QuestionsQuestions• Does air have weight (mass)?

Does air have mass?Does air have mass?• Every object and substance in

the world is made of matter. Matter is the stuff that everything is made of. The amount of matter in an object is its mass. Mass is the measurement of the amount of matter in an object or a substance such as air. Mass is measured in grams.

Does air have mass?Does air have mass?• One way to confirm that

something has mass is to weigh it. Weight is pull or force between Earth and the matter in an object or substance. Weight can vary slightly at different places on Earth and can vary greatly on different planets.

Does air have mass?Does air have mass?• In outer space, away from

planets, objects become weightless, but their mass does not change.

• So let’s restate our question: –Does air have mass?–Is there any matter in a volume of air?

• True or False: The syringe on the left has more air than the syringe on the right. Explain.

EXPERIMENTEXPERIMENT• What experiment can we conduct

to find out if air has mass?

• Materials available:–Round balloons

–Clear straws

–String

–Paper clips

–Tape

You Tube Video about mass/weight, grams/kilograms.

Where’s the Air?Where’s the Air?

Discussion CircleDiscussion Circle• Use the data you collected to

write a few claims (what you believe to be true) based on this experiment.

• DON’T FORGET TO BACK UP YOUR CLAIMS WITH EVIDENCE FROM THE EXPERIMENT!

PURPOSE Does Air have mass?

RESEARCH

What do you know about air and mass already? _______________________________________________________ _______________________________________________________ ______________________________________________________

HYPOTHESI S

______________________________________________________ ______________________________________________________ _______________________________________________________

EXPERI MENT

Materials: Round Balloons, clear straws, string, paper clips, tape, _________________________________________ What is your plan, step-by-step? 1._____________________________________________________ 2._____________________________________________________ 3._____________________________________________________ 4._____________________________________________________ 5._____________________________________________________ 6._____________________________________________________

ANALYSI S

Write down your observations (what happened during the experiment):

CONCLUSI ON

What did you learn? _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________ _______________________________________________________

SHARE RESULTSSHARE RESULTSWhat experiment did you perform?

What were your conclusions, what did you learn?

EXAMPLE EXAMPLE EXPERIMENTEXPERIMENT

ANALYZE RESULTSANALYZE RESULTS• Blowing up a balloon requires forcing air against a resistive force of rubber. The elasticity of the rubber puts pressure on the air in the balloon. The air in the balloon is compressed.

ANALYZE RESULTSANALYZE RESULTS• Compression pushes the molecules closer together. There is more air in the volume defined by the balloon than there is in an equal volume of uncompressed air outside the balloon.

ANALYZE RESULTSANALYZE RESULTS• Two balloons full of compressed air are balanced.

• When air is let out of one of the balloons, the air is no longer compressed.

ANALYZE RESULTSANALYZE RESULTS• The balance tips down, and the balloon full of compressed air sinks because it has more mass than the deflated balloon with very little air.

• Air has mass, thus air is Air has mass, thus air is matter!matter!

READING:READING:“What’s in the Air”“What’s in the Air”

page 6page 6

What’s in the Air ****ANSWER ALL QUESTIONS IN COMPLETE SENTENCES. USE THE QUESTI ON TO ANSWER THE QUESTI ON. 1. What is the diff erence between permanent gases and variable gases in the atmosphere? __________________________________ __________________________________________________________________________________________________________________________________________ ______________________________________________________________________________________________________________________________________________ ________________________________________________________________________________________________________________ 2. During the daylight hours, plants and algae take in carbon dioxide and release oxygen. I f humans continue to destroy rain f orests, what might happen to the balance between these gases? _________________________________________________________________________________________________________________________________________________________________________________________________________________ _________________________________________________________________________________________________________________________________________________________________________________________________________________________ 3. What was the most interesting thing you learned f rom this reading? ___________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ 4. What was the author’s purpose in this selection? A) to entertain B) to persuade C) to inf orm

WORD BANK

• Matter- the stuff everything is made of.

• Mass- the amount of matter in an object measured in grams.