For our fifth project as ninth graders in the STEM program at San Marin, we had to create various models of our solar system. These models had to eventually include in our final two results different calculations and predictions, and they had to be precise. Everyone was assigned to the same groups for this project as the ones for the Solve a World Problem project.

To start the project we were given a task as a group to create a quick 10 minute model of the solar system with only our previous knowledge. This was our model 1 and all groups had only included the planets in order next to the sun. The distances and sizes were not to scale on this first model. Then we were asked to do a little research online and change one factor of our poster to create model 2. We decided to change the distances between the planets to make them to scale. This change was indicated by the blue lines on our poster which pointed to the correct position of the planets. For our model 3 of the project we had to do more research and find certain facts about the planets in our solar system. For example, one of the facts we included was the orbital period for everyone of the planets, which we organized in a chart on our first poster.

For our model 4 we were asked now use all the information we had just learned from our first three models to create a poster that would include a prediction for Planet X, a diagram that must have at least three bodies, and a chart of information. Then we also had to state the phenomenon of our poster, the evidence used to prove this phenomenon, the limitations of our poster, modifications from our past models, and any unanswered questions created from our poster. We tried to predict the orbital period of Planet X by deriving an equation but our answer was about 10 times off of the correct answer. our prediction was most likely so far off because our equation was incorrect, but it could also be because we did the math wrong when calculating. For our last model, model 5, we needed to create to smaller posters. the first had to have four different predictions that would work for any planet in our solar system. For example one prediction we included was the orbital period. Then for the second smaller poster we had to include calculations for Planet X, Planet Y, and Earth. For each planet we had to calculate their orbital period and about how much a person would weigh on each planet.

Universal Law of Gravitation: the law that describes that every object attracts every other object with a force proportional to their masses and inversely proportional to the distance between them. The Universal Law of Gravitation explains what the force of gravity is and how it works.

Gravitational Force: the force of attraction between all masses in the universe. The equation that is used to solve for gravitational force is: F(force of gravity)= G(gravitational constant) times mass₁(mass of the first object) times mass₂(mass of the second object) all divided by d²(distance squared). We first used this equation when tried to derive an equation to find the orbital period for Planet X in model 4. Then we also used this equation when we were finding the weight of a person that would be standing on Planet X or Planet Y in model 5.

Gravitational Constant: the constant in Newton's law of gravitation relating gravity to the masses and separation of particles. The Gravitational Constant is equal to 6.67x10 to the power of -11 Nm²/kg² and is used in the equation for gravitational force.

Inverse Square Law: a law stating that the intensity of an effect such as illumination or gravitational force changes in inverse proportion to the square of the distance from the source. We used the inverse square law in our project to show how the gravitational force of objects is inversely proportional to the distance from the objects.

Orbital Period: the time it takes to complete one full orbit around a celestial body. The equation that is used to solve for orbital period is: T(orbital period)= 2 times π(pi) times r(distance between bodies) all divided by v(orbital velocity). We used the orbital period for planets various times throughout the project. For our poster for model 1-3 we included the orbital period for all planets in our solar system in our chart. Then in model 4 we tried deriving an equation from two different equation to find the orbital period of Planet X. Last of all we found the orbital period using the correct equation for Earth, Planet X, and Planet Y, in our model 5.

Orbital Velocity: the velocity at which a body revolves about another body. The equation that is used to solve for orbital velocity is: v(orbital velocity)= 2 times π(pi) times r(distance between bodies) all divided by T(orbital period). The equation used for orbital velocity is the same as the equation used for orbital period but by doing algebra we could solve for orbital velocity. We used the orbital velocity for planets multiple times during our project. For model 4 we used the orbital velocity of Planet X to try to find its orbital period in the derived equation. In model 5 we used the orbital velocity to find the orbital period of Earth, Planet X, and Planet Y.

Radius: the straight line from the center to the circumference of a circle or sphere. When finding the force of gravity between two masses the distance between the two masses is measured from their center of mass. So for a circular body, for example a planet, the radius is included for the distance between the masses.

Throughout the project we learned many interesting facts about our solar system and even how to calculate various physics problems. We had three main learning targets that we needed to know by the end of this project. These three targets were:

• Newton's Universal Law of Gravitation: I knew this law very well, because we used the law many times throughout the project when we were calculating the gravitational force of an object. An example of when we used this law of gravitation was when we had to calculate the weight of a person on Planet X, Planet Y, and Earth.
• Being able to predict the orbit of an object in our solar system: By the end of this project I knew how to calculate the orbital period extremely well, because my group focused on predicting the orbital period of planets throughout the project. I especially started to understand how to calculate the orbital period after our group had tried to do it by ourselves, but failed because we did not know the equation. This mistake helped me remember how to do it correctly in the future.
• Earth's interior and surface movement: Right after Mr. Williams had taught the class about how thermal convection cycles matter I understood it clearly. This target was very easy for me to comprehend even though we had only talked about it at the beginning of the project.

Even though we stayed in the same groups for this project as the ones for the Solve a World Problem project, we didn't have time to reflect and try to improve our group work. This means that we had the same aspects to work on as a team as the last project. The first improvement we could have made to our group work was to be better conscientious learners. To improve our skills as conscientious learners for this project our group could have managed our time better. For example, when we were creating our model 4 poster we were spending so much time focused on just finding an equation to solve for the orbital period, that we had to very little to write everything on the poster. If our group had divided the tasks for our project in a better manner we wouldn't have as much stress near the end of our project. The second improvement we could have made as a group was to be better communicators. As we were working through our project we didn't explain everything to one partner as well as we should have. For example, when creating model 4 one my teammates was confused because we did not explain the research we had done to derive an equation for orbital period.

As our group continued to work through both of these last two projects we did many things very well. First of all, we did a great job collaborating as group. For example, when working on our projects our group stayed very positive even when we were feeling stressed from having to think critically and work hard. Everyone in my group also made sure that they tried to contribute as much as they could to create the best end result for our project as we could. The second aspect of group work that we did well was our critical thinking. Throughout the entirety of the project we had great times of brainstorming for ideas and solutions, and we also worked our way through problems well. An example of this was when my group was working on model 4 for our project. At first we had no idea what we were going to do for the equation for orbital period. But after a lot of hard thinking and researching we were able to find an equation that semi worked.