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Friday, December 7, 2012

Oatmeal Raisin vs. Sugar Cookies, A Case of Mixtures


Appropriate Age Level
3 +

Science Concepts Learned

Mixture - variable composition; meaning it consists of different things
Homogeneous - visibly indistinguishable parts; everything blends together
Heterogeneous - visibly distinguishable parts; you can pick out different pieces of the mixture

Chemical change - a given substance becomes a new substance or substances with different properties and composition; the components went through a change and can no longer return to its original state.

Activity/Experiment

1. Find two recipes or cookie mixes, one for oatmeal raisin and the other for sugar cookies.

2. First get out all the ingredients for the sugar cookies and talk about all the different items being put together to form what is known as mixture.

3. Mix all components of the mixture together, adding according to the recipe directions.  While mixing and adding items, have the child look at the mixture to see if they can see the different parts of the mixture.

4. When the mixture gets to be smoothly mixed so that you can no longer make out individual components, declare it homogeneous and explain why.

5. Repeat steps 2-4 with the oatmeal raisin cookies.  However, this mixture will never be homogeneous and instead will be heterogeneous.  Explain to the child why its different and ask them what they can still see in the cookie batter that makes it heterogeneous.

6. Bake cookies according to directions.

7. I threw this one in for a bonus, but once baked you can explain to the child that the cookies went through a chemical change, they no longer can be batter anymore, but are cooked and changed chemically. (You honestly can leave this experiment with just the mixtures part, but I thought since it was there why not add it in)

Time Allotted 
15-30 minutes for mixing, follow baking instructions per mix.


References: Zumdahl Chemistry 5th Edition, 2000. 

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