# Fields and Interactions

### Fields and Interactions 15: Evaluating Transport Designs

In this culminating activity of the Fields and Interactions Unit, students revisit the scenario they encountered at the beginning of the unit. "In 2050, an international effort has designed a base station on the Moon. There is a landing site (LAN) in a shallow crater and a habitat building (HAB) outside the crate at a slightly higher elevation. The distance between HAB and the LAN is 1 km and the height difference is 50 m There is a need to move supplies and people back and forth between the LAN and the HAB, so the aerospace engineers decided to make a transport system composed of a track and transporter between the two locations. The transporter will have to work in an environment that has no air, no water, and reduced gravity. Gravity on the Moon is 1/6 of that on the Earth. Designing the transport system depends on how the transporter will be moved back and forth on the track. Since there is no oxygen on the Moon, a traditional combustion engine is not a possibility Also, there is limited availability of electricity. "

Students analyze four very different lunar transporter design proposals. Based on their understanding of gravitational, electric, magnetic, and electromagnetic fields, they evaluate how well each design meets the given criteria and constraints.

### Fields and Interactions 14: Electric and Electromagnetic Fields

In this activity, students use a literacy strategy called, "Listen, Stop and Write" to read about similarities and differences between electric and electromagnetic fields. Students also learn about how these fields are used in new technology development including maglev transportation systems.

### Fields and Interactions 13: Gyrosphere Rescue

In this engineering design challenge, students use what they have learned about the variables that affect an electromagnet's strength to model methods to rescue a trapped gyrosphere that cannot roll. Students apply what they have learned about electromagnetic induction to design a transporter that moves steel bearings from one location to the other, within a set of criteria and constraints. By controlling the variables of wire length, the number of turns in a coil, and the strength of the current, students optimize their designs to transport the bearings for the lowest possible cost.

### Fields and Interactions 12: Electric and Magnetic Fields

In this activity, students carry out investigations to further explore the relationship between electric and magnetic fields. In Part A, students quickly ran a powerful neodymium magnet through a wire coil attached to an ammeter, which measured electric current in milliamps. In part B, students built a circuit to charge a 3v capacitor, which they then inserted into another circuit containing a wire coil and a switch. They placed a compass next to the coil and observed the compass as they turned to switch on, to complete the circuit. Finally, in Part C, after defining electromagnetic induction, they tested which variables affect the strength of a magnetic field around an electromagnet including the voltage of the capacitor, the number of coils of the wire and the length of the wire coil. They use an app from Google called Science Journal to access the built-in magnetometers of their smartphones to measure magnetic field intensity. Students will use the information they learned about electromagnets in an upcoming engineering challenge.

### Fields and Interactions 11: Electric Field Transport System

Students apply what they have learned about electric and gravitational fields to design a hovering transporter cart that depends on electrostatic force to move. Students learn that an electric field can be used to make the transport hover. Similarly, an electric field can be used to push or pull the transport along the tracks. By balancing the force of electrostatic repulsion with the force of gravity, students model how the transporter can hover over the track, similar to the magnetic cart in a previous activity. Since the gravitational field on the moon is weaker than Earth’s, not as much electric charge is needed on the moon in order to make a same-massed transport hover. They use a computer simulation that allows them to manipulate the arrangement of charges as they create and test different system designs. By testing, analyzing data, and redesigning, students combine the best characteristics of each design to make a new solution that better meets the criteria of the transporter.

### Fields and Interactions 10: Visualizing Electric Fields

In this activity, students use a computer simulation to visualize an electric field and to further explore and refine the relationships between force, charge, and distance that they discovered in the previous activity. Visualizing the electric field lines allows students to see why like charges repel and opposite charges attract. Students learn that any electric charge will create an electric field surrounding it that decreases in strength as the distance from the charge increases. The larger the charge, the stronger the field. Equal sized positive and negative charges create fields having equal strength, but are opposite in directionality. If there is a group of opposite charges that exactly balance (or cancel), an electrically neutral space is created.

### Fields and Interactions 9: Electrostatic Force

Students are introduced to a tool—an electroscope—that can show the relative strengths of forces resulting from static electricity. Students plan and conduct their own investigations using the electroscope to see if there is a relationship between the amount of electric charge, the distance between charged objects, and the amount of force. Students then use the results of their investigations and evidence from previous activities to verify that fields exist between objects exerting forces on each other, even though the objects are not in contact.

### Fields and Interactions 8: Static Electricity

Students ask questions about and then investigate how static charge can sometimes cause objects to be attracted to, and at other times repelled by, each other. By rubbing certain materials together to generate static electricity, students are able to observe that these interactions provide evidence for forces that act at a distance, which means that they can be explained by fields that extend through space. Students use a simulation to further investigate the crosscutting concept of cause and effect in regard to phenomena related to static, since charged particles occur at scales too small to observe.

### Fields and Interactions 7: Gravitational and Magnetic Fields

After several hands-on activities, students used Pear Deck to navigate a reading activity to learn more about gravitational and magnetic fields. Students synthesize their knowledge of gravitational and magnetic fields in a through the text that compares and contrasts these two kinds of fields and helps students summarize what influences the magnitude and direction of forces resulting from field interactions. Students also reflect on how energy stored within a system of interacting objects relates to the relative positions of the objects interacting. These relationships are examined through the lens of the crosscutting concept of cause and effect. Students extend what they know about fields to incorporate more complex ideas about magnetic and gravitational fields. Through a Reading and follow-up discussion, students better understand phenomena relating to these fields. Students also learn about how these fields are used in new technology development such as MRI (Magnetic Resonance Imaging).

### Fields and Interactions 6: Magnetic Transport System

Students investigate the properties of different types of magnets and design a new transport system that is driven by a magnetic field. Students build and test a series of prototypes of magnetic hover carts where they can change the size of the cart and the number and types of magnets. Students then attempt to optimize their hover carts to carry the maximum possible mass all the way across the magnetic track using only magnetic fields to propel the carts.

### Fields and Interactions 5: Mapping Magnetic Fields

Students use magnets and a compass to identify properties of a magnetic field. They discover that placing a compass near a magnet allows them to map magnetic field lines. By carefully examining their magnetic field line maps, the students can see evidence of locations where the magnetic fields are stronger and where they are weaker. They also gather evidence that magnetic fields are an example of force at a distance.

### Fields and Interactions 4: Gravitational Force

Using the Google Sheets App, they graph the gravitational force between the moon and a imaginary future lunar satellites. Students compare the gravitational force of smaller and larger mass satellites orbiting at the same distance, and of satellites of equal mass orbiting at different distances. Graphing the data allows students to begin to understand the relationships between gravitational force and mass, as well as gravitational force and distance. Through analyzing and interpreting data, students learn about the relationship between the gravitational force between two objects, the mass of those objects, and the distance between them. Students create and analyze graphs demonstrating that gravitational force is directly proportional to the mass of the objects and inversely proportional to the distance between them. Students connect their analyses with their previous investigations and experiences to further understand how a system of gravitationally interacting objects has both forces acting on the objects and potential energy stored between the objects.

### Fields and Interactions 3: Gravity Transport System

Students encounter another future lunar scenario, and begin modeling parts of the engineering challenge. "In 2050, an international effort has designed a base station on the Moon. There is a landing site (LAN) in a shallow crater and a habitat building (HAB) outside the crate at a slightly higher elevation. The distance between HAB and the LAN is 1 km and the height difference is 50 m There is a need to move supplies and people back and forth between the LAN and the HAB, so the aerospace engineers decided to make a transport system composed of a track and transporter between the two locations. The transporter will have to work in an environment that has no air, no water, and reduced gravity. Gravity on the Moon is 1/6 of that on the Earth. Designing the transport system depends on how the transporter will be moved back and forth on the track. Since there is no oxygen on the Moon, a traditional combustion engine is not a possibility Also, there is limited availability of electricity. The engineers consider that, at least in the direction of the HAB to the LAN, the transporter could be driven by gravity."

Students used ramps, tracks, carts, blocks and cylinders to model how varying heights and masses affect the amount of force imparted to objects. This hands-on modeling helps students to develop a working understanding of Gravitational Potential Energy (GPE), and how GPE could be harnessed for a lunar transport system. Students use a system model to investigate how the release height and/or mass of a cart affects the amount of kinetic energy transfer in a collision. Through a process of testing, evaluating, and redesigning, students optimize their solutions by controlling the initial amount of gravitational potential energy of the transporter. They use this model to make conceptual connections between their evidence and explanations of gravitational potential energy.

### Fields and Interactions 2: The Apollo Missions

Students learn about the extraordinary history of NASA's Apollo Lunar missions in this text based activity. From launching the first US astronaut in space in 1961, NASA managed to land humans on the moon just eight short years later in 1969. The students learned about the engineering design process scientists, engineers and mathematicians used to design, test and build rockets powerful enough to send astronauts to the moon, as well as the many failures the engineers had to overcome. The text also features the contributions of two female NASA pioneers, mathematician Katherine Johnson (featured in the film Hidden Figures), and computer scientist Margaret Hamilton.

We have also started learning about NASA's plans to return to the moon in 2025 with the Artemis mission. One thing students noticed is who crewed the Apollo mission versus who will be crewing the Artemis missions. Coincidentally, one of the Artemis crew, former Caltech Post Doc Jessica Watkins, visited the Beckman Auditorium at Caltech on Friday, April 7 at 5:30pm to give a lecture on Her Journey to the International Space Station and More. Dr. Watkins could be the first woman to walk on the moon! Several Waverly Middle School families attended the talk to learn more from this incredible planetary geologist and astronaut.

### Fields and Interactions 1: Save the Astronaut

Students are introduced to the process of engineering with a scenario that engages them in solving a simple problem. "It is the year 2050. There is an international project to create a moon base on the Moon. During one of the exploration missions, an astronaut on the surface of the Moon is stranded when her personal vehicle called a “gyrosphere” stops working. The gyrosphere is out of power, but it is still able to roll."

The process of solving the problem is compared with and contrasted to the work of scientists and engineers. Students then generate questions and define problems in their everyday lives. The activity elicits and builds on students’ ideas about how to define a problem and develop a successful solution. Students consider the role of forces at a distance due to gravity and magnetism in their solutions.