Elements, Mixtures and Compounds

We are currently doing a unit about mixtures, elements and compounds. I love the practical side of this unit, but the students often find it challenging. I have made a concerted effort to keep this unit "real" this year. Two effective contexts have been food science and disasters. I hit a bit of a stumbling block when it came time to teach about the Periodic Table of Elements, but I will talk about that shortly.

DISASTERS

Most of my students lived through the earthquakes of 2010-2012 in Christchurch. They remember the need to purify water, liquefaction, and all of those sorts of things. This gave me some authentic contexts to talk about what mixtures are, and ways we might separate them.

My favourite one was the challenge to clean up muddy water, with the intent that we would want to cook with it, or drink it. I loved that the students remembered that boiling and/or chlorine/bleach tablets would be needed to make it safe to drink, even if it looked clean. They were provided everyday items from home - coffee machine filters, sieves, dishcloths etc. 

Sadly, I forgot to take some photos of the contraptions the students set up to clean the water. Please trust me when I say there were a lot of FAIL moments (First Attempt In Learning). Ultimately though, they all got some water that I would happily drink after it had been boiled.

FOOD SCIENCE

This has been great!! Today, we learned about the difference between physical changes and chemical reactions. There are great experiments around for this, but I wanted to use the same reactant, and make it real. So, I decided on sugar. Some recipes ask for you to melt sugar, some ask you to caramelise it. What is the difference? How do we actually achieve this?

Success!!!

I also used food to help demonstrate the difference between a mixture and a compound. While our actual experiment was using iron and sulfur, the students were challenged to relate this to making biscuits or a cake. We have recorded the instructions in our CLASS BLOG.

IN THE NEIGHBOURHOOD

As a Science teacher, I love the Periodic Table of Elements. It is a road map, a bible, a multi-tool...I have so many analogies. I was thinking about a fun way to teach about the elements and the Periodic Table, in particular. This idea came to me:

The Periodic Table of Elements is a city. Every city has its suburbs. In Periodi City (do you like that??), these suburbs are called: Transition, Alkali, Earth, Halogen, Noble, etc.

Choose a "house" in Periodi City. Which neighbourhood is it in? What is that house made up of (protons, electrons and neutrons)? Who are your neighbours? Who are your closest "relatives"? Who are your best "friends", or are you found on your own? What happens when you spend time with your "friends"? Is there anyone you don't like? Why?

The students then report their findings as a short (three-slide maximum) PowerPoint, a creative story, or an A3 (maximum) poster. This has been so much fun so far!!! I am going to write and narrate my own creative story for an element this week, to model how much fun they are "allowed" to have with this. I will put it on YouTube, if you care to look for it...