Journal

August 24th, 2010

         The rat trap car we have designed is long and thin.  Because it is a larger car, the shape must curve in order to glide through the air.  Measurments must also be exact; any flaw could prevent the car from running smoothly and efficienly.   It will be about two feet long and nine inches at the widest.  The car must have enough room to hold a rat trap and a seat for Stuart.  We plan on either using a helium filled balloon to make the car zoom through or a solar powered fan as a backup, which would run slowly but keep the car going.  To ensure that our car will go, we will follow Newton's three laws.

Newton's First Law:  An object in motion tends to remain in motion, and an object at rest tends to stay at rest.

Newton's Second Law: Force equals mass times accelleration.

Newton's Third Law: For every action there is an equal and opposite reaction.

August 25th, 2010

    Today, our group has made really good progress.  We have used all our materials and started to build our rat trap car.  Although we had trouble putting the wheels on, we figured it out.  Our car is turning out to be a lot smaller than we planned.  The scale is now between six and twelve inches (one foot).  We are making the axils out of wooden dowels and the base for the car out of balsa board.  Like all our other materials, the wheels are also wood.  To hold it all together, we are using wood glue and rubber cement.  Although the car is almost built, we are experiancing difficulty trying to shape the car and the wheels.  We also have changed our plan a little by using Co2 rather than helium. 

    August 26, 2010

            We are becoming frustrated with our rat trap car.  We tried using balloons to make our car go forward.  Following Newton's first law, for every action their is an opposite reaction, we assumed that the air blowing one way from the balloon would force the car and push the car another.  We tried using multiple balloons however we believe that the car is too heavy.  The friction caused by the car itself, such as the wheels being heavy (made out of wood) and the body of the car not being heavy enough to cut through the air, is a problem.  If the car cannot move and the resistance is there even before the car begins to move, we are not sure how we are going to deal with the friction if it moves.  Unfortunately, we do not have the proper materials to use our back up plan, with solar power.  We may have to rethink our plan.

August 27, 2010

        As we continue to build our car, we have more and more ideas.  Either using a rubber band or some sort of elastic band, we want to fling the car.  Another idea we have is using a mouse trap tied to a string that when set off, will make the car zoom forward.  Friction is the main problem.  Well the wheels of the car are way too heavy, the body of the car is too light.  The car does not have the right constistancy.  THe measurments of the car are now 12 inches by 4 inches.  Now that more laws have been made, we must make sure that our car qualifies.

August 30th, 2010

    Our car has begun to break.  Although it is a pain to rebuild the car, it might be for the better.  The car we originally made was not running efficiently.  We decided to come through with the mouse trap ideas.  We were able to put the rat trap to the front of the car and all we will need is string and a pencil.  In order to make the car glide through the air we are going to cut semi circles out of the sides.  The dementions are pretty much the same since we are mostly only going to work on the wheel and axils and making the car more sturdy.  So far, the progress we've made is good and our car is very slowly comming together. 

August 31st, 2010

   Although we hoped to use a mouse trap to get the car to move, the idea wasn't working to well.  We have figured out another way for the car to be self propelled.  It consists of a rubberband that we attatch on the edge of the wheels.  The rubber band holds on to the wheels so when it is wound backwards, it can have the opposite reaction and fling forward.  Unfortunatly, the car will only go the lenth of the rubberband.  The longer rubberband gets tangled easily and still does not go the distance nesassary.  Maybe we can try using string or some other material.  So far the car has gone a record of three meters in five seconds.  The car now weighs 133 grams.

September 1,2010

Today we have decorated our car.  Our car is slowing when when it should be accelerating in speed.  We believe that this is caused by the rubber band's inability to glide through the air.  The car is too light at the top to be able to fight the friction from the air and the rubberband dosn't help to much with that.  An idea that we had to get rid of the rubber band was surgical tubbing.  Surgical tubbing is used for IVs and other medical uses, however we hope it can help us in this situation.  String does not contain anything elastic so it cannot stretch or work in this situation.

September 2, 2010

                We tested the car today using surgical tubbing.  The elastic in the tubbing was not stretchy enough to get the car moving so we are back to the rubberband.  In the car we cut a hole for the rubberband to fall through and allow the car to keep moving even after the rubber band has stopped unwinding.  Though the mouse trap did not have any real function, we kept it to add to the car's mass and fight the friction in the air better.  The results from the rubberband arn't as good as what we expected.  The car has not much changed but its record is six meters in 8 seconds.  The car is not ready for race day yet.  We will use a fresh rubber band, one that is not worn, on race day. We still have some more things to improve and ajust on the car.

September 3, 2010

Today we have tested the car, while it was running we noticed that the rubber band was following Newtons 3rd law. (for every action there is an equal and opposite reaction. When the rubber band is let go it unravels so the axil moves along with it causing the car to go into Newtons 1st law of motion (an object in motion tends to remain in motion, and an object at rest tends to remain at rest.) When the rubber band unravels it moves the axils which moves the back wheels the way the rubber band is unraveling so in our case forward, but if we were to set the rubber band backwards it would travel backwards, when the back axil makes the car start to move the front wheels which are round so all 4 wheels are moving the car.  

         September 7, 2010

Our rat trap car uses Newton's Laws by:  When we wind the rubberband one way, it goes in the oposite direction, or forward.  The car runs by Newton's 3rd law, For every action, there is an opposite reaction.  The car continues to go by Newton's 1st law.  An object in motion tends to remain in motion and an object at rest tends to remain at rest.  Our car only stops when friction slows it down.  The floor being uneven, the particles in the air, and other forces, cause the car to decrease in speed.  We used Newton's laws in the making of this car to ensure it would go. 

September 8th 2010

          We worked on the blue prints today and have found that it is exactly 12 inches long.  the back and front are both 4 inches.  Although it was originally a rectangle, we have changes the shape a little.  Its shape is somewhat like an hour glass.  Although we've had several ideas that we thought were perfect and thought to stick to, we finally have decided to keep the rubber band.  The car is not going much farther than three meters, and we cannot think of any other way to make the car go faster or farther.  One idea was cutting the tube holding the axil a little shorter to add more room, but we are afraid it might take the axil apart.  The other idea we had was to rap the rubber band over and over again, but it becomes tangled.  The biggest problem with our car is that it is unpredictable and is not reliable.

September 9th 2010

    Today, we were able to test the car several times and find the accerleration, velocity, and force.  As we continue to make improvements on the car, we found a way to make the rubber band turn the wheels faster.  The more it is stretched, the faster the wheels spin and the farther it goes.  So far the car is running really well, however, we have broken a number of rubber bands.  Right now, our main focus is to make sure the car continues to go and to complete our charts and blueprints.  Race day is almost here so we hope it will be ready by that time.

September 10th 2010

                  We were not able to test our car at all today.  We worked on the charts for velocity, acceleration, and force.  We also worked on our force diagrams.  After adding a few finishing touches and looking at the laws, we think our car might be ready.  The car does not break any rules so we are sure it will pass. Though there was a little bit of debate on how we were going to race our car, we are going to do the straight track.  The wheels are to on too stiff to try to turn and the car goes almost perfectly straight now.  We do not have a lot of time left as well.

September 12, 2010

                            Today we are going to work on our force diagrams.  We now understand, using the diagrams, what is slowing our car down and how we can fix it.  The surgical tubbing, which we do not yet have, is our last hope.  To allow our car to go faster, we have increased the length of the dowel which the rubberband winds on.  The car will only go as far as the lenth of the rubberband at the moment.  Although we have built the car in a certain way to ensure that it will keep going even after the rubberban has unwound, the car cannot build up enough momentum to continue going.  The surgical tubing, which will be longer and able to stretch farther, will hopefully help the car to build up momentum and at least make the car go 10 meters, or the length of the goal.  The car measurments have not changed, and the wheels unfortunatly have begun to wear down.  I hope we can fix up our car within the next few days.

September 14, 2010

    Today we completed the blueprints for the car. The car is also complete.  Since tommorow we are doing a walk around, we will not have anymore time to work on the car.  Today was officially our last day.  Our finished product is not perfect but it moves and isn't too slow.  The measurements and weight have not changed at all.  We are ready for race day as long as our project is approved tommorow.