Friday, 28 August 2015

Elements and Atoms

After exploring the Periodic Table we decided to delve in a little deeper and explore what exactly makes up an atom and how does that relate to the periodic table?

First off we discussed how atoms were discovered.  After reading this very informative post from Our Worldwide classroom we talked about how around 400 BCE the Greek philosopher Democritius experimented with trying to cut gold in half as many times as he could.    He called this unit the atom which in Greek means "uncuttable".  
In 1910 this experiment was replicated with gold foil by Sir Rutherford.  L tried it out with a piece of paper and scissors.  I think she managed 17 cuts.  According to Google you would need to cut it in half 31 times to get it down to an atom.  L thought that was pretty impressive.

We then watched this excellent Youtube video on atomic structure which helped us to learn about protons, neutrons and electrons and how the number of protons in the nucleus is how the atomic number is determined.  We also learned how there are different atomic shells which hold a certain number of electrons.  

After watching the video L was able to figure out how to make models of different elements.  
This is where the fun really began.  We headed down to the beach and collected a bunch of black similar sized stones.  We then separated them into three piles for protons, neutrons and electrons and painted them each a different colour.  (Even little brother had his own pile to paint).  Once dry we put the electrical charges on them.
As you can see in the pictures L used her hula hoops for the outer shells and using her periodic table was able to create the atoms of different elements.

She also made a 3d model of an element as a mobile.  It turned out really cool but we had a bit of a time getting there.
L decided she wanted to make the element titanium.  It was all well.  She'd figured out how many protons by the atomic number and then the number of neutrons by subtracting that number from the atomic weight.
The number of electrons was also easy and we thought which shells they went in was straight forward according to the rules of the video we watched.  Well after much Googling by the parents we finally figured out that several transition elements actually don't fill up the third shell before adding another shell.  It gets very confusing so I won't get into it here.  My brain still hurts!

Anyhow the final product is stunning.  It was really simple to make.  L glued pompoms together for the protons and neutrons in the nucleus.  We cut out different sized pieces of cardboard for the outer shells and L painted them sliver then glued on the electrons to their appropriate shells.  We hung them all with invisible thread.  What a great way to visualize an atom!

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