Subject: What is the most correct representation of bond in diatomic oxygen?

I am working on developing a molecule-building kit for jr. high to early 
high school students.  While obtaining feedback from various educators we 
had one comment that the double bond between oxygen atoms (in diatomic 
oxygen) is actually a single bond according to new studies. I've been 
searching for documentation of this and the closest I've come is an answer 
on your website stating that the bond is weak and more like a 1.5 bond.  
What would be the correct way to represent this?  I am thinking that using 
a double bond will suffice, along with an explanation that the bond is 
actually weaker than double. Thank you!

Re: What is the most correct representation of bond in diatomic oxygen?