muscle, bone, skin, and all--made up of? How do these
cells use the air? Why do you need to breathe so often? 5. In the
candle experiment, is all the air under the glass used up? What is
used up? How can we compare a person in a closed room to the burning
candle under the glass? 6. What is the gas that we breathe out? 7. In
what three ways does the body "clean house"?

IV. FRESH AIR--HOW WE BREATHE IT. 1. Where are your lungs? 2. Draw a
picture of the ribs. 3. In what position are they when the lungs are
filled with air? In what position is the diaphragm then? 4. What are
the lungs giving off in the breath besides carbon dioxid? How can you
prove this? 5. How can you prove that the gas in your breath is not
like the gas in the fresh air around you? 6. Why does a room with
people in it grow very warm if the doors and windows are kept closed?
7. How does Nature keep the outdoor air clean? What makes the winds?
8. Are you careful to keep your breath as clean as possible? How? How
do you help keep the air in your house clean?

IN SCHOOL

I. BRINGING THE FRESH AIR IN. 1. What do we mean by fresh air? Why
must the air we breathe have oxygen in it? 2. Is the air in the room
now the best you can have in it? How is the air moving? 3. Is there
always the same amount of air in the room? Then, if there is more
fresh air, there must be--bad air? If there is less fresh air, there
must be--bad air? What is the quickest way to let the bad air out and
the fresh air in? Why are you given recess? 4. What is a draft? Are
drafts dangerous? 5. Will night air hurt you? What air can you have in
the house at night except night air?

II. HEARING AND LISTENING. 1. Have you ever slept in a house close to
a railway? What did you notice whenever a heavy train went by? What
made the bed tremble? 2. If you have stood very near a moving train,
how did your ears feel? Why? 3. How far do sound waves travel after
they enter the ear? Could a person be deaf who had two perfect ears?
Where would the trouble be? 4. Draw a picture to show the parts of
your _left_ ear, and name each part. 5. How do you take care of your
ears? 6. Comment on doing each of these things:--firing a bean shooter
at anyone; throwing gravel or sand; firing off a cap or torpedo close
to some one's head; boxing a person on the ear; running a nail cleaner
or pencil point into your ear; putting on the baby's cap so that the
ears are folded forward; asking your teacher to repeat her q