P.E.O.P. -- How many drops of water can sit on a face of a penny?

 

One of the discrepant events that works well with Smarter Science’s Predict – Explain – Observe – Explain (P.E.O.P) templates is “How many drops of water can sit on the face of a penny?” This activity is simple to set up; all you need is some pennies, medicine droppers and water. The unexpected results will lead to endless fascination, excellent questions, numerous investigations, opportunities to record, plan, design, gather data and experiment as well as  interpretation by comparing, contrasting, analyzing, evaluating, and the communication skills of discussing, explaining, reflecting and reporting.

My grade nine applied science class performed a P.E.O.P. such as this as part of their Culminating Performance Task (CPT) this past semester. The students were given one Canadian penny, a medicine dropper and the P.E.O.P. template at the introduction of the activity. This allowed all the visual learners to see just what size the dropper and the penny were prior making their predictions.

Students were instructed to make their predictions using an “If . . .then . . “ statement in box one of the template and to include a diagram. Predictions ranged from 2 to 8 drops with the mean being 4 drops of water.

In box two of the template they were to explain why they had made their predictions. Most of them wrote something along the lines that “pennies are small so not much water would fit on them”. In my class of 19 students there were neither outstanding or startling predictions nor explanations.

After completing box one and two of the template the students then got beakers of water and began their experiment. This may have been the only moment of time, during the entire semester, that my classroom was silent! The students were intent on this task, it thoroughly captivated them. Quite frankly they couldn’t believe what they were observing! They wanted to repeat it over and over again to ensure that their results were indeed reproducible, just like “real” scientists! Eventually, yet begrudgingly, I had them stop their experimentation so they could complete their written work and thereby provide me with documentation towards their final mark. 

In box three of the template the students recorded how many drops of water they were able to fit on the face of a penny, incredibly the highest number was 54! Although each and every student had disproved their initial prediction they were proud of their accomplishment and insightful in explaining their reasoning into why their predictions were wrong.

This simple P.E.O.P. allowed my students to not only engage in a rich, authentic task but it also allowed them to demonstrate their critical thinking skills while demonstrating how they have evolved into real scientists over the semester, not only in the all of their actions that are described above but also in the fact that they are no longer discouraged when their initial hypotheses is wrong, an outcome I had despaired of achieving!

P.E.O.E. on the Process of Drying Fruit

 

Have you used the Predict – Explain – Observe – Explain science process so eloquently summarized up by the Smarter Science student–friendly template? Also known as the P.E.O.P., this simple method really gets your students to think, and provides a means for you to access their critical thinking skills.

Recently I used the P.E.O.P. template with my grade nine applied students during an investigation into drying fruit. We had already studied the water cycle so the students were familiar with the term and process of “evaporation”.

On order to access their prior knowledge I initiated a class discussion into dried food. Our class is very multicultural but everyone had some form of dried food they were familiar with, most commonly dried banana, dried papaya, dried mango, raisins and beef jerky. Together we brainstormed about the “drying” process. “What happens when food is dried?”

 The analogy I used was, “What happens when clothes are dried?” The students were quickly able to extrapolate that if drying clothes means removing the water then drying fruit could mean the same thing. There was some discussion around the “juiciness” of fruit and whether the juice is just fruit-flavoured water.

The students worked in pairs for this activity. They had previously been instructed to bring in a fresh fruit or vegetable from home. Since half of the class forgot to bring something in the instructions were to pick a partner where at least one of you had a fruit or vegetable. The produce our class worked with included oranges, carrots, bananas, apples and celery.

Using the first square of the Smarter Science P.E.O.E., Predict, the students made their predictions by making an “If . . .then” statement in this format:

If my apple is sliced up and dried then it will . . .

The students were also expected to draw a picture showing what would happen.

In the second box on the P.E.O.E., Explain, the students had to explain WHY they had made their predictions. This is our first glimpse into their thinking process!

Once the first two boxes of the P.E.O.P were completed the students were instructed to prepare their fruit in whatever way they thought would be most suitable for drying. This caused some initial confusion: Should we peel it? Should we slice it? Should we cut it in half? Because the students are to take ownership of their learning my reply was consistently, “What does your partner think?” Eventually all of the pairs were able to take a risk and make a decision.

In the third box of the P.E.O.E, Observe, the students had to make some initial observations about their prepared samples. Although they were told only to rely on physical properties (those they could detect with their senses) the fact that I had put out our electronic balances that day allowed many of them to infer that recording the initial mass of their samples might be a good idea. Other observations the students made included colour, smell, and texture.

 

When the students returned to class on Monday they rushed to the windows to see what had happened to their samples over the weekend. Some of them wanted to eat their results right away! Pairs with differing types of samples were comparing their changes with no prompting from me. In fact, the students quickly weighed their dried samples and started calculating the amount of water lost without any top-down instruction. The learning just flowed. 

The students recorded their final mass in the third box of their P.E.O.E. as well as any other differences they observed.

In the final box, Explain, the students revisited their initial prediction (box 1) and stated if it was correct or not. They used the evidence they had collected to justify what had happened to their predictions. This is where their critical thinking skills are showcased!

Once again, Smarter Science had allowed the students to OWN their learning! How have you used the P.E.O.E  in your classroom?

How does particle size affect the rate of dissolving? -- An Student Designed Inquiry

 As part of the Culminating Performance Task my grade nine applied science class used the Smarter Science emergent scientist templates (poster set three) to design and conduct an inquiry into the effect of particle size on the rate of dissolving. The solute we dissolved was store bought Alka-Seltzer tablets and the solvent we used was water.

Due to the nature of the learners in my class I assumed that some of them would have no prior knowledge of Alka-Seltzer. So I started the class by showing them the box I had purchased from the drug store, then I opened the box and showed them the packages within and finally I opened the packages and showed them the tablets. Next I showed them Alka-Selters advertisements from Youtube then I dropped one of the tablets into a beaker of water and demonstrated how to time the dissolving process from beginning (initial time) to end (final time). 

While demonstrating the last step I invited the students to pull out their digital devices and use the timers on them to help with the timing. This step allowed the students to become familiar with the timing devices they didn’t even know they had, as well as become aware of the importance of starting and stopping the timer at precisely the right moment in order to record accurate results. Because I had a limited number of tablets available and an even more limited budget with which to purchase more I wanted to ensure that no tablets would be wasted during the actual lab due to failure to record the dissolving time. 

Using the Smarter Science template the students determined that the independent variable for their investigation would be the particle size while the dependent variable would be time (rate). The controlled variables would be:

1.      Size of beaker

2.      Volume of water

3.      Temperature of water

4.      Mass of tablet (predetermined by pharmaceutical company)

5.      Timing device

Each group was given four tablets for their investigations. The particle sizes they would experiment with were:

1.      Whole tablet

2.      Whole tablet broken into halves

3.      Whole tablet broken into quarters

4.      Whole tablet crushed

Each group decided what values to give to their controlled variables and recorded them on the Smarter Science template. Once everything was planned and recorded in an intelligible fashion the students were given their four tablets and got down to some serious science.

This lab worked very well. After performing and recording the investigation the students cleaned up, washed their hands and began analyzing their results. Because most of these students are visual learners I had them use their data to construct a line graph. The results were universal, the crushed tablet dissolved at a much greater rate than any of the other formats. In their written report the students reflected how this knowledge could be used in their daily life. Most have decided to chew their prescribed tablets in the future instead of swallowing them whole. 

 
What labs have your students designed and conducted to investigate the effects of particle size on the rate of dissolving?
Can you recommend any less expensive solutes?