Friday, May 1, 2015 – written by STEM Facilitator Bori Kim
Another beautiful day in Chicago! The first day of May, spring is here (we still had a load of snow around this time last year). The girls may be distracted if it is too beautiful outside like this, so there must be something fun that wins over this spring breeze. Luckily, Ms. Angelina Jaimes, a Project Exploration STEM Facilitator brought so much fun and even practical science into our Funston Sisters4Science session!
Ms. Angelina set up the materials on a table and the girls and I sat around. White Vinegar, Lemon Concentrate, Salt, and Water. The girls were so excited to see these simple materials or ingredients that made us think we were about to “cook” something. Then, Ms. Angelina showed us a bag of pennies. Old, dirty pennies. A-ha, we are not cooking! “We are cleaning these pennies only with these materials here. I will demonstrate first then you are all going to make them clean,” said Ms. Angelina. She put one tea-spoon of each in a clear plastic cup and let pennies sink into lemony water. “Ok, now it is your turn girls,” said Ms. Angelina handing them out the clear cups.
“Since we have a small group of girls, what about experimenting with four different variables?” I added an idea. “Yes, that’s good idea,” agreed Ms. Angelina. I gave them a direction, “So, you have four options girls. You create those options for yourself and see which one makes your pennies cleanest.” “Ms. Angelina and I want to see the cleanest, purest pennies.”
“Can I taste these before we do?” “Can I too?” the girls so wanted to taste them so we let them do. They wanted to figure out which ingredient would play a major role to clean the pennies by tasting. Very creative and cute idea!
“Oh my, I love vinegar,” said Victoria. “Really?” Julie asked and tried it with her baby finger then “Yikes!” she screamed.
“Okay girls, let set up your four variables.” “Oh, one more question for you. What is penny made of? If you know this, it might be easier to come up with variables.” I explained a bit more to help the girls think critically. “Oh, it’s copper,” said the girls in unison. “Good. So try it.” I encouraged them.
The girls were very engaged in figuring out which mixture would work best forpennies. One cup without water, but the rest of ingredients. One cup with less vinegar than others. One cup with more lemon than vinegar. All different variables the girls have set up.
“I think salt,” said Emely, “because I put one cup of salt with a spoon of others. This one is cleanest,” pointing her cleanest pennies. “Wow, one cup of salt! That’s a nice try.” I complemented her. “What about others?” asked Ms. Angelina. “I think lemon, the acid does something,” responded Julie. “That’s a good guess too” Ms. Angelina said.
Looking at their cleanest pennies, we all agreed that the salt plays a more important role than other ingredients. Without all ingredients, however, the pennies would’ve never had a chance to take a bath.