A hypothesis that we came up with and tested: If hand washing is the most effective method for not spreading germs, then washing hands for 10 seconds will show fewer germs than rubbing had sanitizer for 10 seconds. Variable to change: method of cleansing hands Variables to keep constant: amount of glo-gel used, time spent cleaning, amount of hand sanitizer used, water temperature, how hard we rub hands Materials: special glo-gel, black light, hand sanitizer, kitchen sink (soap and water) | Result: We were correct. But we also discovered that 10 seconds is not enough. Also we were surprised that the hand sanitizer didn't seem to get rid of the lotion much at all. Resulting question: what good is hand sanitizer? Speculation: the 70% ethyl alcohol kills germs Can we test this in class? Sadly, no. Other variables we could test, just with water: Washing with soap and without soap. Washing in different temperatures of water. How hard one scrubs. How long one washes. |
Playing with water—you observed that:
- boiling hot water dissolved 12 teaspoons of salt in less time than it took to dissolve 3 teaspoons in room temperature water
- adding salt to ice lowered the temperature from 0 degrees Celsius to -10 degrees Celsius, while at the same time appearing to melt the surface of the ice. How can both be true? Investigate further!
- adding salt to liquid water lowered the temperature from 70 degrees Celsius to about 50 degrees Celsius?
Other things we did today:
- Practiced some hypothesis worksheet questions
- Read through information about Matter
- Card sort activity about the science process skill definitions, sub-skills, and examples
- Brief explanation of chemical formulas, using H2O and CO2 as examples
HOMEWORK:
- complete the 2 hypothesis questions (one question per handout)
- create 2 quiz questions, with answers, based on the 3-page reading about Matter and Properties of Matter (chemical and physical)
VOCABULARY
Science Process Skill words:
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