Can We Prove That Air Has Mass?

Student: I love this class.

Teacher: All right last class we learned that density is a measurement of how heavy something is in comparison to how big it is. Now then, what do we need in order to figure out density?

Student: We need to know how heavy it is also how much space it takes up… Volume?

Teacher: Correct! Now is air heavy? Does it have mass?

Student: It doesn't feel any heavier to me.

Teacher: Now class, as you can see I have two different balloons here one filter is breaking point and the other with just a little bit of air. I am going to place each one on either side of the ruler. Who can guess what will happen? Yes, Jimmy.

Student: Nothing will happen, both are filled with air.

Teacher: Let's find out, shall we? Interesting now what just happened? Jill?

Student: The bigger balloon has more air squeezed inside, so it's heavier.

Teacher: Yes, so if it is heavier that means air has mass. Let's think what are some other gases

Student: Helium. Helium must be lighter than air because helium balloons always float away.

Teacher: Perfect example. Now, let's look at the fish tank and the boat. Can you predict what will happen when I place the boat in the tank?

Student: It will fall to the bottom.

Students: Ah!

Student: That is s so cool but how?

Teacher: Chris?

Student: Yes, Mr. Lumpart?

Teacher: Maybe you can tell us why this is?

Student: Because the tank isn’t empty.

Teacher: So if the tank isn't empty, what is in the tank?

Student: I don't know.

Teacher Hmm. Even though it appears to be empty the tank is filled with a gas five times more dense than air and because of its mass it pools in the tank just like water would.

Student: So the boat floats just like it would in water.

Teacher: Exactly! Now class, what did the chemist say about the book he was reading on helium? He couldn't put it down