The Solids and Liquids Module provides experiences that heighten students' awareness of the physical world. Matter with which we interact exists in three fundamental states: solid, liquid, and gas. In this module second graders have introductory experiences with two of these states of matter, solid and liquid.
While brushing my teeth this morning, I put toothpaste on the brush. It squeezed out of the tube, and was easy to shape, but it sticks to the toothbrush.
Is toothpaste a solid or a liquid? How do we describe toothpaste?
Toothpaste is a mixture of powdered solids and various liquids, so it is neither a liquid nor a solid. Chemists would argue that toothpaste is a colloid (like milk or ink): a mixture where tiny particles of one substance are dispersed evenly into another without separating out. Toothpaste is a mixture of some solids and some liquids. When the toothpaste dries out you can see what the solid part alone looks like.
Answering the question, however, involves the ability to describe matter by observing its properties, and using those properties to describe and classify it. Early investigations help students develop words to describe the materials. (1.1, 1.2, 2.1, and 2.2). Activity 1.3 – The Tower Challenge – it a quick side tour that flows off describing properties of solids. By discussing properties of different solids, students explore engineering by building a tower.
In 3.2 or 3.4 (only one is really needed – your choice.), students explore how solids of different sizes mix, and how they can be separated by sifting. The see that particles of solids will have some properties of liquids – they pour – but they also maintain their shape. This working towards the idea that objects can be made of a small set of pieces can be disassembled and made into a new object – a building block for the idea of atoms and molecules, though these concepts are not expected to be discussed.
In 4.1, students explore what happens when adding various solids to water. Some don’t change, some absorb some water and some dissolve. It is easy to separate the first two by draining the liquid, but how about when it dissolves? Evaporation is when the water “dries up” and the solid material is left behind.
The documents below have been created to help consider the FOSS materials in the context of the Next Generation Science Standards. We recommend you review, at the very least, the following documents:
Unit Guide - A summary of materials, sequencing and content for the module.
Storyline - An overview of the sequencing and reasons for the various activities
Assessment - A collection of assessment tools including what to look for as students work on the activities.