# 14 August Science 8 Matter–investigating water and more

Beginning routine and plan for the day:

1. Mindful moment.
2. Review entry from DSN from previous class.
3. Preview blogpost for today.
4. Set up entry for today’s DSN entry.
6. (Perhaps: Why study matter? Why use the example of water? (See this excerpt From Nobel Laureate Richard Feynman’s Lectures on Physics):

“If, in some cataclysm, all of scientific knowledge were to be destroyed, and only one sentence passed on to the next generations of creatures, what statement would contain the most information in the fewest words? I believe it is the atomic hypothesis (or the atomic fact, or whatever you wish to call it) that all things are made of atoms—little particles that move around in perpetual motion, attracting each other when they are a little distance apart, but repelling upon being squeezed into one another. In that one sentence, you will see, there is an enormous amount of information about the world, if just a little imagination and thinking are applied.” <http://www.feynmanlectures.caltech.edu/I_01.html>)

7. Share aloud with the class your reflections/questions from your previous DSN entry.
8. Lab procedures and techniques. NOTE: ALWAYS WRITE EXPECTATIONS BEFORE CONDUCTING A PROCEDURE.
9. Fair tests. Controlling variables.
10. Balance–importance of mass in observing matter:

11. Measuring cylinders.

12. Sinks, counters, class supplies, working neatly, thinking procedures through–flowcharts, clean-up, SAFETY.

13. Continue working on the questions from the last class and some new related questions. If you have questions of your own, please pose them for the class.:

A. What happens when a piece of floating ice melts in a container of water?(Many people expected that the water level would rise. Can you explain their reasoning?)(S0me people said that the water would not rise. Do you follow their thinking?)

B. What determines whether something floats or sinks?

C. Determine the density of water. How would you do that? (Hint: Density is the mass of a sample of a substance and volume is the space taken up by the same sample. Mass is measured on a balance and volume of a liquid can be measured in a measuring cylinder. Ask if you need clarification on the technique.) Discuss with your group. ALWAYS WRITE EXPECTATIONS BEFORE CONDUCTING A PROCEDURE.

E. What happens to the mass of a cube of ice when it melts? What is your explanation for what you expect? Discuss with your group. Make notes of your ideas. Test your ideas. Ask if you would like to discuss the technique. There are some aspects that can affect the results. ALWAYS WRITE EXPECTATIONS BEFORE CONDUCTING A PROCEDURE.

F. How could we relate the question about ice floating to icebergs? The icebergs that calve from glaciers are fresh water. If they fall into the ocean, they are floating in salt water. How salty is the sea? Are some ares of the oceans saltier than others? What can you find out. Discuss with your group. Will a piece of fresh water ice float differently in saltwater than in fresh water? What do you expect and can you explain your thinking? Can you test your ideas? Be sure to careful make note of what you do and what results you observe. ALWAYS WRITE EXPECTATIONS BEFORE CONDUCTING A PROCEDURE.

G. Here is an old puzzle? Which melts faster: An ice cube in salt water or an ice cube in fresh water. Of course, the ice cubes would need to be the same mass, volume, and shape, and the container of salt water would need to be the same temperature as the container of fresh water. Try to conduct a fair test of your ideas? ALWAYS WRITE EXPECTATIONS BEFORE CONDUCTING A PROCEDURE.

H. What about the density of salt water? How could you determine the value? Do you think the concentration of salt water would affect the density? How might you express how salty a sample of salt water is? ALWAYS WRITE EXPECTATIONS BEFORE CONDUCTING A PROCEDURE.

I. What other questions about water occur to you? Any thoughts about evaporation for example?

J. Here is a very nice essay about water by the science writer Natalie Angier. What do you think. Read it and write a response. Is there anything in the article that sheds light for you about the questions we have been investigating?

Small, Yes, but Mighty: The Molecule Called Water

https://www.nytimes.com/2007/07/10/science/10angi.html