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!


Air Pressure

This week, Jane ran a very succesful new activity about air pressure. To start the activity, Jane lead a discussion about air and did a demonstration using a notecard to seal an inverted cup of water. This demonstration really surprised the girls and lead to an interesting discussion about how air molecules are pushing on the bottom of the notecard (although there are other forces involved, we kept it elementary school level).

After the demonstration, the girls split into two stations to learn about air pressure:

  1. Build a Hovercraft
  2. Balloon Race

At the hovercraft station, the girls constructed their own hovercrafts using a balloon, a CD, a bottle cap (with a small hole already through the top), and a glue gun. One at a time, the girls used the glue gun to connect the cap to the center of the CD. This was actually really fun because many of the girls had never used a glue gun, so as some side science, we learned how the glue gun works and how to use it safely. Then, we blew up the balloons, twisted the balloon so no air leaked, and connected the balloon to the bottle cap. When the balloon untwists, this creates a hovercraft that feels very similar to a hockey puck on an air hockey table. Then, we placed pennies on the hovercrafts too measure the strength of the air pressure. 

At the balloon race station, the girls blew up balloons and attached them to the “racing track”, which was a cylinder paper around a string. When the full balloon was released, the balloon flew along the string, demonstrating how the air leaving the balloon generates enough force to move the balloon along the track. This was really fun, and lead to some exciting balloon races! We also tried the races with different shaped balloons, which were a big hit.

Overall, this was an awesome activity!

EGGcellent Fun

This week we had an egg-cellent time learning about the properties of eggs! We had the girls rotate between three stations:

  1. Determine if an egg is hard boiled without cracking it. At this station, Radost taught the girls that if they spin or roll the egg, the raw egg wobbles more because it has a yolk bouncing around inside! I thought this was very clever.
  2. Learn how to make an egg float in water. I helped run this station and had a blast teaching the girls how to make an egg float. First, we hypothesized whether the egg would sink or float in tap water. Answers were about split: half thought it would sink and half thought it would float. I love having the girls hypothesize what is going to happen before these types of activities. It gives them an opportunity to use their previous knowledge and intuition AND makes the activities more suspenseful! After watching the egg sink in water, we passed around a container of salt and each girl added some salt. I let them know that, with enough salt the egg will float– and it did! We had to add a lot of salt though! This led to a nice discussion about density.
  3. Test the strength of an egg shell. At this station, the girls had to crack 2 eggs, clean them, and balance books on the four half-egg shells. The girls were very impressed at how strong an egg shell is, considering we are so used to cracking them. This was definitely the messiest of stations!

    I think its wonderful to “do science” with a common item, like an egg. What a great activity!


For this activity, we used our recent knowledge of light and optics to make kaleidoscopes. The kaleidoscopes turned out awesome! First, we reviewed some facts about light we learned two weeks ago:

  1. White light is a mixture of many colors.
  2. Light travels in a straight line.
  3. Light can pass through an object, be blocked by an object, or be reflected off an object.

For this activity, we focused on #2 & #3 and the word “reflection“. As a warm-up activity, we challenged the girls to bounce a beam of light off of three mirrors. This took some precision and help from the mentors, but eventually was a success!


After bouncing light of of multiple mirrors, we began the construction of our kaleidoscopes. This involved designing a pattern to look at through the scope, as well as building the triangular mirror structure (made out of mylar) to put inside the tube.

Once the kaleidoscopes were complete, the girls had a blast looking through their kaleidoscopes. They even took pictures and videos through the kaleidoscope, which was awesome!

For more info on how to make the kaleidoscope, check out the activity worksheet: GSC_Kaleidoscope

Creepy Density

Because it was the week before Halloween, we planned an activity that explored density, but put with a creepy Halloween twist! We started by talking about what density is, and showed the girls pictures of a box with lots of colored dots and a box with few colored dots. They quickly realized that the box with fewer dots represented a lower density. Then, we explained that a lower density liquid would float on liquid with higher density.

Next, it was time to start the activity! We started by pouring the highest density liquid (honey) into the bottom of the cups. We then proceeded to pour the other liquids into each girls’ cup in order of density. We added maple syrup, water (colored with food coloring), and vegetable oil.

We handed out paper clips, small legos, and candy corn (which they were extremely excited about) for the girls to drop into their layered liquids and see which level they floated on. We talked about how you can compare the density of the solids objects to the density of the liquids by seeing where they stayed in the cup. The cups ended up looking really cool, with the separated layers of different colors, and the girls seemed to get really into it!

Optics and Light

This week we were lucky to be able to explore the science of light using donated photonics kits from the IEEE Photonics Society. The IEEE Photonics Society distributed kits to groups around the world “to show young women and pre-university students how photonics impacts the world around them” through their “Introduce a Girl to Photonics Week” Initiative. The kits were awesome! Thanks!

Radost led the activity and organized it into three rotation stations. Each station was designed to teach the girls different facts about light:

  1. Light travels in straight lines; light spreads out as it gets further away from source. 
    At this station, the girls lined up three index cards. They shined light through the holes in the index cards, moving the middle card. This activity demonstrated that light travels in a straight line!
  2. You can make new colors with light; white light is made up of many colors. 

    I ran the color mixing station and had the girls write down their hypotheses of what color we would see when we mixed the different colored lights. Most of the girls correctly predicted that red and blue light would make purple, but not one girl predicted we would see white light when we mixed all three. This was a very exciting finding! We then looked at the ceiling lights in the room through a film that separates the white light into separate colors.  This provided two different lines of evidence that white light is a combination of many colors.

  3. Light does different things when it hits different materials- it can be blocked or passed through.
     At this station, Radost taught the girls the meaning of the words: opaque, transparent, and translucent. The girls tested the ability of light to go through different materials and categorized the materialized into three categories based on these new vocabulary words. At the end, the girls were given a mirror to test, which demonstrated that light can also be reflected!

At the end of the three rotations, the girls had the choice to (1) read about light in the books provided, (2) experiment with the colored lights, or (3) make a color wheel.

Overall, we had a blast learning about light!



Measuring & Play dough

Note: From now on, I will be posting a link to the “Activity Sheet” at the bottom of each post. This week our theme was measurements. I planned the activity to convey the importance measuring in science. Before making the play dough, we started with two fun warm-up activities:

(1) Which is more accurate: a graduated cylinder or a beaker? Almost every girl guessed the cylinder, which is correct! Their reasoning was correct as well, “the cylinder has more measuring lines!”– I was impressed!


(2) Next, we gave out syringes and had the girls test their measuring skills with water. Playing with the syringes kept their attention for longer than I expected, probably around 5-10 minutes!


Finally, we made the play dough, which requires 4 ingredients (flour, salt, warm water, and kool-aid). We had the girls line up and measure their own ingredients into their bowl:


Once the salt and the flour were mixed, we had everyone sit down. Before we passed out the water, we had the girls agree that they would stay seated, which I think made the rest of the activity a success. Once the water is added, you are left with this goop:


Because the proportions of flour/water/salt are not perfect, you have to add more flour if it sticky and more water if it is flaky. This demonstrates how important it is to have the correct amount of “stuff” when doing science– it’s the difference between sticky goop and perfect play dough! The girls has a blast trying to get the play dough a nice consistency. By the end of the activity, everyone had a ball of red play-dough (that smells amazing because of the kool-aid!). Unfortunately, we didn’t get any pictures of the finished project– all of the mentors were very busy (and messy) during this last step! The final play dough looked like this:

Here is the activity sheet we used this week: GSC_Play_Dough