Hello Steemians! This post is an entry to the first SteemStem Science Fair! You don't have to be an expert (like me and my trolls) to take part. As long as your methods are scientifically accepted, all you have to do is present us with a question answered by an observation-based theory.
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Since I recently prepared a lesson plan with experiments on the air properties, I thought I should use the same topic for my Science Fair entry, only this time I'd look on a different aspect.
First, let me introduce you to my assistants, the troll team...
...and my friend 
Thank you my dear
What is the question we're dealing with?
Isaac Newton is the father of classical mechanics with his three laws of movement:
First law: An object at rest will remain at rest unless acted on by an unbalanced force. An object in motion continues in motion with the same speed and in the same direction unless acted upon by an unbalanced force. This law is often called "the law of inertia".
Second law: Acceleration is produced when a force acts on a mass. The greater the mass (of the object being accelerated) the greater the amount of force needed (to accelerate the object).
Third law: For every action there is an equal and opposite re-action.
Thanks teachertech for the lovely definitions.
In this experimental process we are studying the Third Law of Mechanics.
Well, my trolls wanted to travel in space, but NASA wouldn't let them in one of their missions, so they decided to build their own spacecraft and make their dream come true. Since they're just trolls and don't have millions to spend on fancy equipment, they could afford simple materials we can get with very little money.
- a balloon
- a straw
- thread
- tape
We fixed the one end of the thread on a chair, put the other end through the straw and then fixed it on our window handle (a higher level than the chair, because we wanted to make our balloon fly). We inflated the balloon and fixed it on the straw with lots of tape. X54 boarded the ship and our first flight was ready to begin.
For those of you who are worried about X54, I should inform you that he is completely healthy and he experienced no injuries during the experiments.
We took several shots, every time the balloon had a little less air because we wanted to check if the distance it would cover would be related to the amount of air in the balloon. Guess what... the less the air, the shorter the distance.
- So why is this happening? my trolls asked.
- Well, according to Mr Newton, there is always a balance in the forces applied to a body. For each force (action) there is always another equal force but of the opposite direction (reaction). The air coming out of the balloon's end pushes out and moves the balloon upwards.
- That's how rockets fly to space? said X42.
- Yes, according to this principle when the rocket ignites the exhaust gas, the gas pushes against the thruster and the thruster pushes against the exhaust gas. This leads to the gas and rocket moving in opposite directions, just like it happened with our balloon.
- But our balloon never got into space! X31 complained.
- Because it did not have enough air to get that far. Spacecrafts use different kind of fuels, more powerful than air. I'm afraid you won't get to the stars in a balloon my lovely curious trolls. But you know what? I have an idea! We can build you an air-fueled car to travel the Earth! come on! I'll show you how.
Materials
- four bottle caps
- 2 wooden sticks
- 3 straws
- a piece of carton
- tape
- a rubber band
First, we're making holes in the bottle caps...
...and we're putting two of them through the sticks.
Then, we're making five holes in the piece of carton (we will use a cereal box because it's already folded).
Now that the holes are ready, we cut the drinking edges of the two straws and put them through the holes like this...
The sticks are going through the straws...
...and then we're taking the balloon, taping it on the drinking edge of the third straw and wrapping the rubber band around (not too tightly, we want to be able to blow it).
Our next move is to get the straw with the balloon through the fifth hole and fix it over the other two straws like that...
We are allowed a little treat for our work now!
- Yeah 
- Sure trolls!!
- Woohooo!! It's working!! But how? X54 asked.
- Just like
- Exactly, said X42. We filled the balloon with air through the straw. Then, we let the straw's end loose and the air coming out of it started pushing our car forward.
- Now we can travel anywhere!! cheered X31.
- As long as we have strong lungs I guess, said X54.
* All photos by
In this point I'd like to thank again my friend
See? I even got your name on my car! You're welcome for a ride with my trolls anytime!
For those of you who are interested in science, Mr STEMonster would like you to consider supporting the 
To the ones that stopped by and read my entry I want to say a big thank you! I do appreciate the support you've been showing me!
Until my next post,
Steem on and keep smiling, people!
