Each student will lead their own artifact. However, you may work with others if desired. That is, if people want to pair up, they may do so, but each needs to be primarily responsible for one artifact. The idea is to allow people to give and receive help, but not to create a relationship in which someone is dependent on a partner.
Grading will consist of a combination of appropriateness to the audience (what is the audience, and are the learning objectives appropriate), quality / level of polish of the materials, and final write-up presenting the artifact
So first you need to decide who your learner is. What age / age range? Child? A non-technical adult? What are you assuming about their knowledge of physics, math, and computer science (You are not allowed to design for a highly technical college student or adult)? What are their interests? What is important in their life? Make profiles about three very different versions of the same kind of learner. For example, if you choose a 7th grade student, make profiles about three very different 7th grade students. If it is parents, make profiles about three parents. Each profile will be about half a page and will describe the individual, answering the questions I posed above. Label this section Defining the User.
Next, you need to think about the setting of the learning activity. Is this in school? An after-school program? A museum? Home? Will there be a facilitator? Take a few paragraphs to describe the setting(s). Make sure you aren't too narrow in your definition of educational settings. For example, one might think zines have no educational setting, but they can be passed out at museums, science fairs, and used as companions to other learning activities. Label this section Educational Setting.
A parent, volunteer, or teacher? Make a profile of this individual. What is their knowledge of physics, math, and computer science? What are their knowledge strengths, and what might they be nervous about? Label this section Facilitator Profile. If you are assuming that there is no facilitator, make sure you meet with me because it may be that you need to expand the target educational settings.