Candy Chromatography

This week we learned about mixtures and color theory using food dye. Mixtures can be combinations of any two or more things, and one easy way to understand this is by looking at primary colors (red, blue, and yellow) and the secondary colors that are mixtures of those (orange, purple, and green). In this activity, we used water to dissolve the dye off the surface of an orange, purple, or green Skittle. By dipping a paper towel strip with a drop of dye into a solvent called isopropanol, we watched the dye separate into the primary colors in the mixture. This technique is called paper chromatography, and it makes for fun and colorful science!

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Blog post written by Julia Marrs

 

Marble Run

For this activity, we created “marble runs” out of recyclable materials. The girls split up into teams of 2-3, came up with their own design, and built it using tape, cardboard, paper and plastic bottles. I tried to film the marble going down the track in slow-motion video, but I couldn’t catch it! Here are some of the creative designs:

Elephant Toothpaste

This week, we spent most of girls science club trying diagnose the issue with our experiment. After many tests, we finally got it to work! Although this was not planned, problem solving is a huge part of being a scientist (and a graduate student…), so overall the hour was a success!

The experiment we attempted was called “Elephant Toothpaste“. As the name implies, the experiment entails creating a foam (from a chemical reaction) that looks similar to toothpaste you might expect an elephant to use. First, Sarabeth showed the girls a YouTube video of the experiment and we laid out a tarp to make cleaning efficient.

The reaction combined two solutions: (1) hydrogen peroxide + food coloring + dish soap with (2) warm water + yeast. Every girl got one mini water bottle to create their own reaction. We went around the room one at a time to test them. We were all very excited and then… nothing happened! The girls were very keen on figuring out why the reaction failed, so we tried different iterations of the experiment including adding more of each ingredient, warming up the water more, and speeding up the mixing. In the end we got it to work once, but I am still not sure why because we couldn’t replicate it.

Sometimes science experiments don’t go as planned and thats ok. We had a blast trying to figure out why the experiment failed and got to use our deductive reasoning skills.

Horizontal Windmills

Wow! This past week I left Girls Science Club smiling and thinking, “that is exactly how girls science club should be”. Jess planned an awesome activity designing horizontal windmills. The activity was pretty free form. We gave out supplies (a wooden stick, a styrofoam ball, thin popsicle sticks, index cards, and tape) and said, “design a windmill”.

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Here are some things that made this week so amazing:

  • Confidence: At the beginning of girls science club, I was working with a girl who spoke very little english. She was extremely hesitant to participate in the activity, so I  helped her make some blades. After some work, she was the first girl to get her windmill spinning. Everyone in the room clapped and cheered when she got it to work! She had the biggest smile on her face and spent the rest of the hour testing different blades and helping other girls get their windmills spinning.
  • Teamwork: Everyone was helping each other position the blades to get the windmills spinning. The blades needed to be able to catch the wind and spaced evenly enough so that the windmill didn’t get stuck.
  • Creativity: All of the windmill blades looked different. There was even a windmill with star shaped blades! And a “cat themed” windmill!

By the end of the activity, there was a consensus that larger blades spin faster and that the blades worked best if they were perpendicular to the wind. Overall, this was a great activity that kept everyone engaged for the entire hour.

 

Static Electricity

Every week at the end of girls science club, each girl “tells us what she has learned” and gets to pick a small token to take with her. We used to give out candy, but have switched to stickers and balloons (to be healthier!). Balloons are the current hot item, so I thought incorporating balloons into the actual activity would be fun! To incorporate balloons, I themed the activity around static electricity.

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The hour was divided into four activities:

  1. Stick a balloon to the wall. In this activity, we had the girls rub the balloons either on their heads or with wool socks/sweaters, and then stick them to the wall. It was also neat to see the balloons stick to the wool socks! IMG_7885.jpg
  2. Then, we tested out which materials can generate static. We rubbed different types of spoons (wood, plastic, metal) with the wool and tried to “pick up” salt and pepper. One girl spilled her salt on the table and used the balloon to pick it up! I thought that was a great idea!IMG_7890
  3. After determining that plastic was the best spoon material to generate static, we rolled aluminum cans with the balloons. To do this, you rub the balloon and put it near (but not touching) the can.
  4. Lastly, we made butterflies with tissue paper wings. To get the wings to “flap”, we rubbed the ballon and put the ballon near the tissue paper wings.

Thankfully, it was a cold day in Boston and the heat was on high, allowing us to generate a lot of static!

 

 

 

 

Lava Lamps

In this weeks meeting, we made our own lava lamps. This is an awesome activity because it visually demonstrates the concepts of density, solubility, and chemical reactions. I strongly recommend this activity!

To start, we gave out an assortment of objects including: rocks, styrofoam, different types of sports balls, wood, and coins. Then, we predicted which items would float in water and tested our hypotheses. After some discussion, it was concluded that, “things that are lighter than water float in water”, which is exactly right! Here, we introduced the word density.

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Testing out objects: Does it float or sink?

Next, we passed out the water bottles and filled them with 1/3 water and 2/3 oil using a funnel. This step demonstrated that oil floats on top of water because oil is less dense than water.

Then, we added food coloring. We explained to some of the older girls the word “solubility” and how the food coloring can be dissolved in water, but not oil.

Finally, we added the most exciting ingredient… Alka-seltzer! The chemical reaction between Alka-seltzer and water creates CO2 gas, which allows the water to bubble up through the oil. This creates the “lava lamp” look! If you leave the cap screwed on the bottle, the bottle pressurizes. Although a few girls did this by accident, it demonstrated that the chemical reaction was creating a gas.

For extra flair, we added glitter to our lava lamps. At the end, we also gave out the extra Alka-seltzer tablets, which led to many overflowing bottles! Whoops!

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Here is the activity sheet we used: Lava_Lamp_Activity_Sheet

Cleaning Pennies!

Last week, we had the first meeting of the semester! After a month off, it was great to get started with Girl’s Science Club again. And what better way than with some chemical reactions! 

First, Jane led a discussion on chemical reactions. One of the girls said, “a chemical reaction is when you mix two things and there is an explosion!”, which I think is great description of chemical reactions based on our previous meetings. We have done a lot of exploding reactions, so this activity was a nice way to introduce a new reaction that cleans rather than explodes.

For this activity, we had the girls make and label three different solutions: (1) water, (2) water + soap, and (3) vinegar + salt.

Then, we each made a hypothesis which solution would clean the dull pennies the best. On my side of the table, the popular choice was water! We put old, discolored pennies in each solution, stirred, and waited. After about 10 minutes, we examined the pennies and found that the vinegar and salt solution cleaned the pennies the best, making them look new! We explained that this was because the vinegar and salt were reacting with the “dirt” (aka copper oxide) on the pennies.

Then, after removing the pennies from the cup, we gave each girl a new nut to put in the already used vinegar and salt solution. After a few minutes, the nut became dull and looked like the old pennies! This was unexpected and exciting!

Overall, the hour was filled with experimentation. Many girls tried solutions we hadn’t suggested, including salt water, salty vinegar, soapy vinegar, etc. They were engaged and curious, which was an amazing way to start the semester!