Why do some things attract each other and other don’t? Students observe phenomena in which: A balloon sticks to the wall after being rubbed on hair; (A plastic bottle picks up small pieces of paper after being rubbed on cloths; Etc …) Students collect various data from demonstrations, experiments, and an interactive simulation. Students use the data to note patterns in how charged objects interact. This simple activity highlight the idea of bulk scale phenomena being explained by atomic scale structures.

The formatting and presentation for this sticky tape experiment is from the NGSS Rollout 3 Lesson written by Maria Simani and Laura Henriques

Why do some things attract each other and other don’t? Scotch tape investigations: Observe how objects become charged; Identify patterns of how charged objects interact with each other; Begin to develop a model to explain these observations.

Getting a Charge Out of Tape Each person in your group will use two 1-2” pieces of tape to become electrically charged by following the steps below. 1. Fold over one end of the tape to make a non-stick handle. 2. Stick this piece of tape to the table (or back of the tray). Label the handle “B,” for bottom. 3. Get the second strip of tape, and fold it in the same way. Place it on top of the first piece of tape, and label the handle “T,” for top.

Getting a Charge Out of Tape 6. Both pieces of tape are now charged. Experiment with your partner to see how the pieces of tape interact with each other when you bring them close together in different combinations. 4. Using the non-stick handles, lift both pieces of tape off the desk at the same time. Then touch the entire length of the strip on both sides with your fingers several times. 5. Pull the pieces of tape apart, making sure to not touch the tape anywhere except on the non-sticky handles you made.

Talk and write your observations What happens when you bring the pieces of tape close together in each combination (T-T, B-B, and B-T)? Based on your observations, what patterns can you identify when two pieces of electrically charged tape are attracted to each other and when they are repelled? What causes the T and B pieces of tape to move toward or away from each other? Discussion Review students’ results. After students share their data, help them identify patterns. Discuss why those patterns occur and how those patterns might be used to make predictions about interactions between other charged materials. Students should recognize the following patterns: Two of the same type of tape (T-T or B-B) repel each other, and two different types of tape (B-T) attract each other.

Students’ models Develop a model to explain the observations of how the scotch tape strips interact with each other.

Developing a Scientific Model The model is a simplified representation of a system or phenomenon Central features of the model are made explicit and visible (including those that are not visible with eyes only) – components of the model The model allows to say something (explain) about what is happening – relationships among the components of the model Appropriate labels are included to clarify the model’s components Makes thinking VISIBLE Teacher hat

What you may know from prior experience as a science teacher All objects are made of particles/atoms. Particles/atoms are made of positive and negative charges. Same charges repel; opposite charges attract. This behavior is similar to magnetism. At this point, we may not be able to explain how neutral objects become charged, or why neutral and charged objects are attracted to each other. In order to answer these questions and explain the observed phenomena, students need to understand atomic structure. (This is NOT an elementary topic but it is something we can try to understand as adults) In preparation for developing a model of atomic structure, this investigation provides evidence that materials are made of particles and thus provides a review of 5-PS1-1. (Develop a model to describe that matter is made of particles too small to be seen.) The review is necessary because students often do not have a conceptual model of the particle structure of substances. This model prepares students for an introduction to atomic structure that includes protons and electrons, which can be used to explain electric forces that occur between objects. The atomic model prepares students for using the concept of electric forces between particles to

Examples of students’ models What are some limitations to our model? (Potential answer: We still don’t know the charge on each tape strip.) ● How might we eliminate some of these limitations? ● What else do we need to figure out?

Summary of students’ ideas from prior knowledge and scotch tape investigations Objects can be positively charged (+), negatively charged (-), or uncharged (neutral). Objects with the same charge repel each other; oppositely charged objects attract each other. Students may also say… The distance between charged objects affects the interactions between them. The closer they are, the stronger the interaction. The amount of charge on charged objects affects the interactions between them. The greater the charge, the stronger the interaction. Charged objects generate an electric field in the region around them. It is through the electric field that charged objects interact with each other. This is what students may say at this point.