Reflections of a chemical dad

I have to admit that the colour change was not a pronounced as I was hoping for with carbon dioxide dissolving to form carbonic acid. In the past I have used other pH indicators which give a much bigger colour change. This is due to the relative high pKa of carbonic acid ~ 6 in contrast to acetic acid in vinegar (pKa ~ 4). I’m keen to repeat this using a different indicator and possibly just blowing into a solution using exhaled carbon dioxide to change the pH. This is a very important demonstration as it simply shows the effect that our carbon dioxide emissions have on the pH of the ocean. Acidification of the oceans is a topic that has not really been raised in the climate change debate but a very serious problem that is looming...

We now tested what happens when you mix acids and bases. What I really like about this video is that you can see that some of the concepts have been sinking in. In particular Matthew has learnt how to use the colour chart and is testing his own ideas like what happens if we add more.

The first time we tried to make this video I did not have the colour standards in the backgroud. Matthew really didn't get the concept. After discussion with a more experienced science educator (my wife) I change the way we ran the experiment and used the colour standards. They definately helped get the point across. Testing soda water really was a spur of the moment idea and definately got us thinking about where it fitted into our colour scale - make sure you watch to the end to see this. If you would like to see our first attempt - here it is. Sorry about the lower quality. It is really interesting to see how much more Matthew was able to understand through using the colour standards. In our first take when I asked him why things were happening he kept coming back to “they are made of chemicals”.

We started a series of video looking at acids and bases. Fittingly we used purple cabbage as our pH indicator. What I love about the first video is that Matthew eats the cabbage during it - this really highlights the important point that everything is made up of chemicals (currently a very 'dirty' word).

Here is our second video and the first under the title of "Khemistry kid" It was really interesting to Matthew start to think about why we can't fill the glass up and how that relates to how much oxygen is in the air. I have also noticed that he still remembers what combustion is a few months later....

This was the first video we made. It really was inspired by #RealTimeChem week and was very spontaneous. I was washing up the dishes watching the oil moving around and changing when I added the dishwashing liquid. I thought - hey I could make a video of this with my son.... Interestingly at first I wasn't going to use the dialogue between me and my son. My wife told me I should and that gave birth to the khemistry kid :-)