{"id":191,"date":"2015-09-16T20:15:15","date_gmt":"2015-09-16T20:15:15","guid":{"rendered":"http:\/\/horizon-research.com\/wp-test\/?page_id=191"},"modified":"2025-10-29T16:50:18","modified_gmt":"2025-10-29T20:50:18","slug":"salt-stirred-into-water","status":"publish","type":"page","link":"https:\/\/www.horizon-research.com\/ASSET\/matter\/driving-questions\/salt-stirred-into-water\/","title":{"rendered":"What happens when you stir salt into water?"},"content":{"rendered":"

\"salt<\/a>Print<\/a><\/a><\/p>\n

Navigating this Pathway<\/h3>\n

This pathway poses a question to students: What happens to salt when it is stirred into a glass of water? (Abraham, Grzybowski, Renner, & Marek, 1992; Abraham, Williamson, & Westbrook, 1994; \u00c7alik & Ayas, 2005; Johnson, 1998; Liu & Lesniak, 2006; Nakhleh & Samarapungavan, 1999; Papageorgiou & Johnson, 2005)<\/a> We recommend having students write the driving question, \u201cWhat happens when you stir salt into water?\u201d in their science notebook and\/or displaying this question prominently in the classroom throughout the pathway. Students begin by making predictions about the weight of salt and water when mixed together (more, less, or the same as when separate). Next they draw pictures of the saltwater using \u201csuper strong glasses<\/a>,\u201d more powerful than the strongest microscope. They then consider whether it is possible to separate the salt from the water, and observe what happens when some of the saltwater is left in the sun. The students then engage with computer simulations representing salt dissolving in water, in order to gain a better understanding of dissolving in relation to the particle model. Finally, the students revisit their super strong glasses drawings and revise them using their emerging understanding of the particle nature of matter.<\/p>\n

Connections to Other Pathways<\/h3>\n

Part of this pathway relies on students\u2019 understanding of evaporation, so it would be helpful to engage students with the \u201cWhat happens to the water in a puddle? \u201d pathway before engaging with this one.<\/p>\n

Teacher Content Background<\/h3>\n

All matter is made of particles that are too small to see, that are in constant random motion, and that have empty space between them. \u201cEmpty space\u201d is literally empty; that is, nothing at all is between the particles that make up matter. All particles in one state are still present even after matter has changed states; no particles are added or destroyed. In addition, the size and shape of the particles does not change. Therefore matter (and mass, or weight) is conserved (stays the same) during phase change because all of the particles present in one state are present in the other (and no more or less).<\/p>\n

When dissolving salt in water, the movement of and collision between the salt and water particles causes the particles to break apart. Neither salt nor water particles are destroyed. When the water evaporates from a mixture of salt and water, all of the original salt particles will remain.<\/p>\n

Student Thinking<\/h3>\n

Students have many misconceptions when it comes to dissolving. For example, common student explanations for the phenomenon of dissolving salt in water include:<\/p>\n