Exploring Energy: Sound, Light, and Heat

Over the next several weeks, we are going to explore the various STEM standards. First up is Physical Science! Here are some experiments and lessons to help understand the fundamentals of energy!

Sound

Grades: 2nd – 4th

Supplies: 

  • Empty bowl 
  • Rubber band 
  • Plastic wrap 
  • Sugar crystals (preferably colored)

Procedure: Cut a piece of plastic wrap and tightly cover the bowl.  Put a rubber band around the wrap and bowl. Place a small amount of sugar crystals in the center of the bowl.  Have a student get down close and say their name (watch as the crystals move). Try again, but change the voice tone – louder, softer, singing voice, high pitch, whisper, etc. 

Science: The movement of the crystals is not caused by your breath, but by the sound of your voice.  Sound is created by vibrations and different pitches create different vibrations.  In our experiment, the sound vibrations caused the plastic to move, which made the crystals move.  Higher notes mean the vibrations are moving faster and students observe more movement among the crystals.  Low notes mean the vibrations are moving slower and students observe less movement among the crystals.    

Follow-up: Have students make other sounds, such as flicking a rubber band or banging two objects together and observe the movement of the crystals.   


Light

Grades: Middle School

Supplies: 

  • Two pieces of white paper
  • Tape 
  • A well-lit white screen / wall / sheet of paper

Procedure: Roll both pieces of paper lengthwise and create two tubes that are 11 inches long and a half inch in diameter. Tape the tubes to keep them from unrolling. Squash one tube so the opening becomes a squished oval. Hold up one tube to each eye and look at the white screen.  Angle the ends of the tube so the two spots appear to overlap.  Do you see a circle or an oval?  Switch the tubes and repeat the steps.   

Science: The eyes and brain have trouble merging the two shapes.  Most people have a dominant eye and the brain will choose to see the image that is coming from the dominant eye (ex. If you held the oval shaped tube up to your left eye and saw an oval, your dominant eye is your left).  Some people don’t have a dominant eye and will instead see the two images overlapped.

Follow-up: Conduct another experiment to verify your dominant eye. Cut a hole in a piece of paper, hold the paper away from your face and look through the hole at an object. Slowly bring the paper to your face and the hole will end up over your dominant eye. Is the student’s dominant eye the same as their dominant hand? This is not always the case!

Fun fact: The best hitters in baseball do not have a dominant eye.         


Heat

Grades: 4th – 6th

Supplies:

  • Balloons
  • Candle
  • Lighter / matches
  • Water

Procedure: Blow up a balloon (3/4 of the way) and hold it an inch or two above a lit candle.  It will pop.  Fill another balloon ½ way with room temperature water and hold it above the candle.  It will not pop.

Science: For something to rip or break, there needs to be some weakness in the material. Things break when enough energy is added to the material to rip apart the bonds between molecules or to make a small defect get bigger. The balloon filled with air:  The balloon melts a bit when it is held over the flame and creates that weak spot.  The air inside the balloon pushes out on the melted part, the weakness gets bigger, and the balloon pops.  The balloon with the water in it:  This balloon conducts heat and is able to transfer it to the water without damaging the balloon (the water absorbs the heat).  Because a weak spot is not created, it does not pop.  

Follow-up: Introduce students to fractography, or the study of the fracture of surfaces of materials (aka, how things break).  They are commonly used to determine the cause of failure in engineering design.  Choose a few materials from around the classroom (paper, eraser, ruler, plastic cup or bottle) and have students try to break them using several methods (their hands, a hammer, their chair).  What does this tell us about the properties of the materials and how does that relate to the function of the object? 

 

References and Resources:
https://www.exploratorium.edu/snacks/circles-or-ovals
http://www.education.com/activity/article/See_the_Science_Sound/