We talked about what an inference is and about how we don't just make a random guess but we use the information and clues we have to make a decision about something.
I gave each table a recording sheet where they had to write down each bottle number, their inference of what was in the bottle, and three reasons for their inference. I started each table with a bottle and then when they had made their inferences we rotated the bottles so that each table go to make an inference for each bottle.
They did surprisingly well! And they came up with great reasons for the inference they had made!
The students loved this activity and it was a great way to reinforce that we can't make random guesses, that we have to have reasons when we are making an inference.
Here are some pictures of the before and after of the bottles: