# Plastic Baggie and Balloon Piercing

• Overview
• Science content focus
• Science practice focus
• Cross-cutting concepts
• Activity sequence
• Resources and materials
• Pedagogical ideas
• Definitions
• Lessons and activities detail

### Overview

Explores the expansion of textual literacy to include all other forms of media.

Properties of matter - Attractive forces in matter - Adhesion and Cohesion

### Physical science content focus

Attractive forces in matter - Adhesive force, acts to hold two separate bodies together (or to stick one body to another). Cohesive force, acts to hold together like or unlike atoms, ions, or molecules in a single body. However, both forces result from the same basic properties of matter. Properties such as surface tension in liquids (cohesion), and capillary action (combination of adhesion and cohesion). Hardness of a diamond results from a strong cohesive forces between the carbon atoms of which it is made. Friction between two solid bodies depends in part upon adhesion.

Supporting ideas from unpacking the big idea

• cohesion;
• attraction.

### Science practices

Use of evidence and reasoning to understand interactions in our world.

Supporting ideas from unpacking the big idea

• observations of pencil and plastic bag with water;
• feeling finger as it pushes through the plastic bag;
• point of pencil is sharp and would start a very small hole.
• Connection of these ideas into cause and effect sequence.
• Evidence can be collected and used with logical explanations to understand and predict changes in the world.

### Crosss cutting concepts - Systems & system models, structure & functions, stability and change

• Cause and effect - poking a pencil into a plastic bag and having it act as a plug with the plastic bag as a gasket to hold the water in the bag
• Stability and change - when objects exert equal forces on each other they are at equilibrium. When objects are not in equilibrium one will displace the other.
• Systems & system models - Drawings can be created to represent and explain scientific ideas.
• Structure and function - the structure of the plastic is elastic to expand and contract to form a tight fit. The structure of the pencil is hard and sharp to create a small hole and expand it for a snug fit.

### Resources and materials

Plastic bag, water, pencil, balloon, pin, oil

### Pedagogical ideas

Demonstration and questioning.

• attraction
• cohesion