A Mysterious White Powder

Help - A mysterious white powder has arrived in a letter.  It could be dangerous.  We need a forensic scientist to find out what it is.

This was the challenge that the science club kids had today.  They were given 6 different powders and had to do 3 tests to find out what they were.

 
The tests were:

• Iodine Test  - This tests to see if the substance has starch in it.  If there is starch it will go black.
• Vinegar Test  - This tests to see if the substance is a base.  If it is a base it will fizz.
• Indicator Paper Test  - This tests to see if the substance is an acid, base or neutral.  If it was an acid the paper goes red.  If it was a base the paper goes green/blue.  If it was neutral there was no colour change.

It's fizzing up with the vinegar!

The substance has changed colour when I added the iodine.  It must be starch.

We used a flowchart to determine what the substance was and recorded our results carefully.

We had to record our evidence very carefully.

 Luckily the forensic scientists identified all the powders correctly (and none of them were dangerous)!