Phase changes are an important part of chemistry and physical science curriculum — and Freeze Pops are an important part of everyone’s summer. What better way to take the edge off the summer heat than combining the two to make a cool activity that addresses changing states of matter?

In the science lab, temperature measurements will help crystalize students’ thoughts around freezing and connect the phase change with particle motion.

To set up this cool experiment, you’ll need to get a base line temperature change of pure water as well as the temperature change of the Freeze Pop. First, pour some water into a plastic container and add a Wireless Temperature Sensor. Next, we’ll open two Freeze Pops (that haven’t been frozen), pour the contents into another plastic container and add a second Wireless Temperature Sensor. Now you can use SPARKvue’s remote logging capabilities and put everything in the freezer. And if you really want to sweeten the inquiry, add some additional Freeze Pops as a tasty post-experiment treat!

The Wireless Temperature Sensor can remotely log data for days, but we’ll only needed a few hours. After letting the samples set overnight, it was time to check the results.

The samples look frozen. Let’s check SPARKvue to see if the data is just as solid.

I started by checking out the water. No brain freeze here— that’s just cool data.

The students will notice that the temperature dropped to 0^oC, and stayed there before dropping again to the temperature of the freezer. But what’s so special about 0^oC and why the plateau?

The students may know that this is the freezing point of water. But they may not realize that the water sample can’t get below the freezing point until the entire sample is frozen. This is where particle illustrations become important.

As the water molecules cool, they slow down into a regularly repeating pattern forming a solid. But why the plateau? As long as there are some faster, freely-moving water molecules in the sample, there will be an equilibrium between the liquid water and the ice keeping the temperature constant. Once all of the water molecules are moving slow enough to be frozen and in the solid state, then the temperature can begin to drop again.

Is the same thing happening with the Freeze Pop? It’s a good thing we have hours worth of data to find out!

This sample, which is not pure water, froze at a temperature that is lower than zero. The freezing point is depressed— but you shouldn’t be. This always happens with a solution. The other particles in the sample (sugar and dyes mostly) get in the way of the solid-liquid water equilibrium and lower the Freeze Pop freezing point.

Students may also note that there is not a flat plateau during freezing. As the water freezes out, the sample gets more concentrated with the “other” particles, depressing the freezing point even more. The freezing slope isn’t steep enough for sledding, but it is definitely noticeable. Once the entire sample is frozen, the temperature decrease is more dramatic.

The concept of freezing point depression is important and it has real practical applications— from making Freeze Pops and ice cream, to car antifreeze and melting ice in the winter.

Now your students can not only understand freezing, but they can explore factors that would affect freezing point depression. I am sure this would open up the lab to 31 flavors of ice cream inquiry!

Most students understand that things get warmer as temperature goes up, but it is in the science lab that we have an opportunity to really help them understand what temperature means. One of the core ideas in Physical Science is that temperature is actually a measure of the kinetic energy of the particles of the matter. But when you’ve only thought about temperature as being hot or cold, this is an especially difficult concept because the “particles of matter” are hard to visualize.

One way to bring this concept into focus is to model the sub-microscopic world with something that the students can physically manipulate. We’ll shake things up in the lab by  modeling molecules with some craft beads.

To measure the temperature, I used a Wireless Temperature Sensor and SPARKvue software. After placing sensor into an empty jar with the beads, I just needed to add some energy. Next step… just shake that jar thing. With a wireless sensor this is easy—just put the lid on and shake it up

I imagine that an entire class of student shaking these beads could be quite a cacophony. These engaged students would definitely see (and hear) the motion of the particles inside their sample of matter. You may need to reign them in a bit and remind them that they should “shake it, don’t break it.”

We know the dancing around turned up the heat in your class, but did all of this movement affect the temperature in the jar? Let’s take a closer look at the data.

One way to bring this concept into focus is to model the sub-microscopic world with something that the students can physically manipulate. We’ll shake things up in the lab by  modeling molecules with some craft beads.

They say fakers gonna fake, fake, fake, fake, fake, but the data doesn’t lie. While the temperature increase was small, we can clearly see that the sensor did measure a steady increase in the temperature.

Now that they have the basic idea of temperature, you can have the students tune their own own investigation to determine the relationships among the energy transferred, the type of matter, the mass, and the change in the average kinetic energy of the particles as measured by the temperature of the sample.

While the students are devising plans (and of course competing to see who can change the temperature the most), you can rest assured that they are understanding disciplinary core ideas and incorporating engineering practices and cross cutting concepts.

Facilitated by veteran PASCO trainer Glenn Starkey, the grade 4 to 6 teachers – representing over 20 schools per session – had an engaging time investigating temperature changes in water and reflective properties of light, as well as learning how to collect measurements with their own weather station. Helping to support Glenn at each session were Craig Ecclestone from AYVA Educational Solutions, and Eric Therrien and Christine Christensen from the Nova Scotia Department of Education.

Over the course of the week, eight separate 3-hour hands-on training sessions were conducted, with representatives from nearly half of the elementary schools across the province. The training was based on the Airlink, the general science sensor and the weather anemometer. The post training feedback was overwhelmingly positive with many teachers commenting that it was the best professional development they ever had to promote scientific inquiry.

“For science teachers who are looking to change their classroom practices and give their students more hands on experience, you need to consider using the latest wireless temperature sensors from PASCO. Using the PASCO Wireless Sensor technology will change the way you teach ….”

Read the entire review blog by Brian Friedlander from Assistive Tek LLC here: http://assistivetek.blogspot.com/2016/06/pasco-scientific-wireless-sensors.html