We did a lot of activities to explore the unique properties of liquids, but this shampoo viscosity lab was definitely a favorite amongst my 6th graders. In order to do this experiment with your class you will need shampoo (I bought white rain for $1.00 per bottle on sale), glass marbles, a stopwatch and a place to keep the bottles at different temperatures. It was super easy to set up!
Students tested how long it takes for a marble to pass through a shampoo bottle kept in warm water, ice and at room temperature. Groups were assigned different scents and tested only one scent throughout the experiment. We talked about how scientists keep many factors constant in order to maintain fairness in their experimental design. This was necessary because I divide my class up into 9 lab groups and I couldn't find a store that had 9 bottles of the exact same shampoo!
(In the past, I have been able to keep these bottles outside in the snow but on the day of this experiment we had a record 65 degree day....just my luck! Having the cooler actually worked out to be easier because I did not have to be concerned with sending students to an exit door to get the cold bottles.)
Students used their phones or ipods to time the marble moving through the shampoo for multiple trials and then averaged their data.
My students recorded their work in their interactive science notebooks using the framework from the packet pictured above. Graphing the data and having a class discussion proved to be a great opportunity to talk about inverse relationships, trends and interpreting graphs.
This activity would make a nice extension to any science unit on properties of matter. If you are interested in more of the materials that I used for teaching about liquids, check out my TpT on Liquid Viscosity!