# How to Make 100+100=192?

Add water to ethanol and find out why it doesn’t add up. It’s similar to what happens when you mix a liter of sand and a liter of rocks. When mixed, the combined molecules fit together better than alone, so they take up less space. What’s more, the OH- component of the ethanol and the H+ of the water molecules are attracted to each other – creating hydrogen bonds. These bonds make a tight molecular formation, reducing the volume of the combined liquids.

Ingredients:

• 100ml of water
• 100ml of ethanol (with adult supervision)
• Three graduated cylinders – two smaller to measure out the liquids, and one larger to mix and read off the resulting volume.

## STEP 1

Measure out exactly 100ml of water and 100ml of ethanol.

## STEP 2

Add the two solutions together in the large graduated cylinder and look at the measurements.

## STEP 3

You would expect the resulting solution to measure exactly 200ml, however it should actually give a volume of around 192ml.

2 hours