The Murky Mystery of Matter Measurement

What am I doing to help kids achieve?
How do I know when they are there?
What is the evidence?

This week I did "The Murky Myster of Matter Measurement" by Chad Bridle. Basically, students are working at making a series of predictions and measurements concerning the mass, volume and ultimately density of two different types of beads.

It can be found at the Grand Valley State University Target Inquiry site. It was the first time I used this activity and I will certainly use it again. It encouraged kids to solve problems multiple ways. It brought in other math concepts. It was an easy set up that can be repeated from year to year. It was well received by students and they experienced success. After it was over, I put away all of the balanced except for one that I had. I challenged some students to see if I gave them a certain volume, could they predict exactly what the balance would say before they placed the beads on the balance? They had still had to do the "pen and paper" but asking them to then physically check it and get instant feedback added a new dimension that was helpful for them and exciting for me to see as a teacher. 

Do you do a cool lab practical with instant feedback??  If so..I would love to hear from you...