Math Night Tonight!

Reminders:
Please join us between 6:00 and 7:30pm for the annual TBS Math Night. Fifth graders will meet in the Cerrito classroom with their families, and fourth graders in Strawberry Creek classroom. Feel free to drop in any time. Details are in Zaq Roberts recent letter.

No Homework tonight: just come to Math Night!

Chemistry Mystery:
Today students tested a mystery mixture of 2 white powders, and did 5 different tests to compare this mystery substance with the 8 substances they tested last week. Recording their observations was very important in being able to correctly identify the substances.

The 8 mystery powders were:

1. salt
2. sugar
3. flour
4. baking soda
5. powdered lime
6. plaster of Paris
7. cornstarch
8. baking powder

Groups were asked to identify the mystery mixture and give their evidence for their hypothesis. The mystery substance turned out to be a mixture of #5 (powdered lime) and #3 (flour). Some groups predicted that #5 was in the mix, based on its pH and behavior with water, vinegar, and iodine, but no one realized that #3 (flour) was there. In general, it was a great example of the messiness and pitfalls of doing real science!

We also watched a short video about mixtures, both heterogeneous mixtures (where you can see the components, like trail mix or concrete) and homogeneous mixtures (also called solutions, where the components are blended together, like lemonade or salt water). Mixtures can be separated into their constituent parts much more easily than compounds, since they are due to physical, not chemical changes. You can watch the video here.