Building a model lung is a great way to participate in a science fair, complete an assignment for class, or learn more about how the human body works.The materials you probably already have in your home can be used to make a model lung.You need a plastic bottle, some straws, a few balloons, hot glue, and a pair of scissors to make a model lung.It is easy to cut through a bottle cap with a utility knife.
Step 1: Use scissors to punch a hole in the bottle.
Use a utility knife to make a small incision in the side of your bottle, 4–5 inches above the bottom.The bottle should be parallel to the horizontal incision.A 20 fluid ounces bottle works best, but you can use a slightly larger plastic bottle as well.
Step 2: With your scissors, cut the bottle into two pieces.
Half of your scissors are inside the bottle if you insert one of the scissor blades into the incision that you made.Hold the bottle firmly in your non-dominant hand, and cut all the way around the side of it with your scissors, so that you end up with a bottle cap and base.You should discard the bottom half of the bottle.
Step 3: You can cut an opening in the bottle cap with a utility knife.
Hold the bottle cap in place with your nondominant hand and then use your utility knife to puncture the top of the cap.Once the tip of the blade is in the plastic, you can carve a small circle by rotating the cap with your nondominant hand and holding the knife at an 80 degree angle.If the bottle cap is too thick for a utility knife, you may need to use a drill bit to puncture the hole.The bottle cap should be secured with a clamps.If you don't like using a drill, ask an adult for help.Don't make the hole too big because you'll be using a straw through it.
Step 4: Try to fit a plastic straw into your bottle cap.
Try to squeeze the plastic straw through the bottle cap.The bottle is ready to go if the straw doesn't fall out of the opening.It is okay if the straw is snug in the hole.A tighter fit will be easier to work with than a looser fit.
Step 5: Attach your scissors to the plastic straw.
Cut the straw in thirds by holding it in your nondominant hand.The places where you cut are even and flat if you use an angle that is parallel to the straw.The sections of the straw should be cut at a 45 degree angle with your scissors.
Step 6: Two pieces of straw should be placed in the bottom of a larger straw.
Put the tip of each straw in the opening at the bottom of the uncut straw.The tension inside the opening will keep the smaller sections in place.The sections of straw should be resting at a 45 degree angle away from the larger straw.
Step 7: Use a hot glue gun to glue the junction.
Before using hot glue to cover the junction where your three straws meet, put a piece of paper down.No air escapes when you use your lung.Let the hot glue dry after a few minutes.If you don't have hot glue, you can use electrical tape.Wrap it in a way that doesn't affect the movement of air in the straw.
Step 8: Put the two balloons on the straws with hot glue.
The hot glue should be near the top of the balloon.The longer length of the straws is still open if you slide them over.You can seal the opening of each straw with hot glue by squeezing the section where you put it.To test it, blow into the open end of your straw.You are prepared to continue if the balloons expand.If you hear air coming out, cover the leak with hot glue.The seal on the straw may end up being too tight if you use rubber bands or tape.
Step 9: You can put the open end of the straw through the bottle cap.
You might have to pinch the opening of your straw to fit through the hole.The case of your bottle has balloons inside.If the bottle cap isn't already screwed on, seal the area with hot glue and screw it tight.The straw will stick out through the top of your bottle cap.You only need 2–3 inches of straw sticking out to make your lung work, so feel free to trim the rest with your scissors.
Step 10: You can cut another balloon with your scissors.
You can pinch the top of the balloon on your nondominant hand.Pull on the balloon with your thumb and ring finger.The balloon should be cut from the top near the section where the balloon's neck begins to fan out.
Step 11: Cut a balloon and put it over the bottle.
Put the balloon out with both hands and stretch it over the bottle.The plastic and balloon are flexible, so it may take a few tries.Wrap the balloon around the area where they meet by using a rubber band or tape.
Step 12: To use your lung, pull on the skin of the balloon.
There are two balloons inside the balloon that cover the opening on the opposite side of the bottle cap.The pressure inside the bottle allows the balloons to take in air, just like your lungs.