When Chemistry Becomes Math Class

At a convention I was at the presenter told the following anecdote:

A group of science educators wanted to see what students' impressions were of Chemistry class. Immediately before the first day of class, the evaluators asked the students to describe what they thought Chemistry was in three words of less. As they expected, words like fire, explosions, reactions, chemicals, dangerous were among those at the top of the list. At the end of the first quarter, the evaluators returned and asked the same question and were surprised at how the students' idea of chemistry had changed. Now words like math class, boring, work were at the top and nowhere could be found words about science.

One of my biggest complaints about typical Chemistry curricula and textbooks are that they start with significant figures, scientific notation and conversions, very little of which has no impact on Chemical principles or the understanding of Chemistry in general, but rather only how students report their answers. I decided to start with actual Chemistry and teach naming and forming ionic compounds. We then worked backward through the curriculum, through the Periodic Table, basic Atomic Structure, and now we are in the dreaded sig figs and scientific notation.

Since I am very activity driven in class I wanted this to be more than notes and worksheets. I trolled Googled looking for "innovative significant figures activity." It is amazing what some people call innovative. Some things I found were webquests, an "interactive" website that was a just a digital worksheet, and an activity that required students to count popcorn kernels. I decided to just make my own.

I went through my sons' toys and grabbed random objects as seen below.

Each student received either a 6 in ruler, 12 in ruler or a meter stick as they walked in the classroom. I then asked them to measure the length of the object in both centimeter and inches and compared the accuracy of both. This part was fun because I made sure the kids with large objects received small rulers and the ones with small objects got the meter stick.

We then calculated the volume of their object. This led to a lot of questions because we needed to figure out what was the better measurement to use for the calculation. After this, we answered the Essential Question for the day which was "How many of your object will fit into this room?" My room is an odd shape so the class needed to figure out how to find its volume as well as make the measurements of length, width and height with meter sticks.

Once each student calculated the number of their objects that fit in the room (the answer really surprised them as many of them had in the millions or even billions) we needed to discuss accuracy of their answers which is where significant figures came in.

As we just finished the Quarterly where they needed to use significant figures and scientific notation I saw a definite improvement in the scores involving those questions. There were still students who got those questions wrong, but I noticed during the exam students who were clearly recalling the rules we used and, hopefully, the activity.

Was this a fool proof method? Absolutely not. Did we have a lot more fun learning about something so dry as sig figs? Definitely!

Girls (and boys) just want to have fun!

Sometimes you need to stop what you are doing and just have some fun in class.  We are working in solutions so what better time to play with a non-Newtonian fluid!  Basically, you need a kiddie pool, 100lbs of cornstarch, 10 gallons of warm water, a bunch of really enthusiastic students, and you have one helluva day.

"It's fricking blowing my mind"

My Honors Chemistry class is just starting to learn about the mole.  For HW (the first one I have given since September) they had to watch the following TED video:

While it doesn't teach them how to use the mole, it got them really excited to learn about how to use it in chemistry.  I started the class with a DO NOW

What, in your every day lives, could be expressed in terms of moles?

I gave them a chance to consider it and then discuss with their groups.  We got some really good answers like sand on the Jersey shore, Doritos, and hair on a human head.  I let them figure out how to calculate hairs on someone's head (someone used their iPhone to Google how many hairs are on a human head.  FYI 90,000-150,000) and we figure it is somewhere in the range of 9x10^-24; they decided that it was not at all useful for every day things.

Then the questions started.

"What if we added up all the hairs on every human head on the planet?"

"What if we added body hair?"

"Eyelashes?"

Someone grabbed a computer and started Googling and found that if you added up all of the cells in every human on the planet, you would only have about half a mole.

The mole is still not useful because the numbers are still unbelievably small.  So then I pull out 1 mole of water (18mL) which is about the amount that fits in the palm of your hand.  

One girl says, "Wait. That's 1 mole? You mean that small amount of water is the same as if we covered the Earth in 5 miles of donuts?! This is fricking blowing my mind!!"

I love it when it clicks.

What I've been up to

I have been terrible about blogging this school year.  One of the reasons I started this blog is to showcase the  fantastic things that happen in my classroom so I want to share some of that with you.  This year I decided to balance the boring aspects of my curriculum with some exciting (an over the top) activities to get my students excited about science again.

At the end of October, my supervisor asked me to perform a science demo for a group of 8th graders to keep them from choosing to go to a magnet school in the area.  Originally I was going to go with the typical Hydrogen balloon explosion or even shooting a T-shirt across the auditorium.  But then I came across this video on YouTube.  I looked at this and immediately said "I NEED TO DO THIS!!"

So here is the video of my demo.

I used about 1L of Liquid Nitrogen and covered it with 1500 ping pong balls.  I found them on Amazon and it cost about $100 with free shipping.  I apologize for the shakiness of the video; it was taken by a student on  my phone.

Doing this experiment inspired me to raise the bar a little on my demos.  A few friends of mine took the cornstarch and water demo to the next level by filling a small swimming pool with the stuff.  The video does not contain my friends.  I figured if they could do it, so could I.  I went to a Restaurant Depot near me and bought 300lbs of cornstarch (yes, 300 POUNDS!).

It turned out my pool was too small and I only used 150lbs, but now I have some for next year!!  We added about 10 gallons of water to the pool and, voila!, I turned seniors into Kindergartners.

And let me sophomores truly express themselves

And just let them explore science.