Every LED light has a "band gap". Electrons are pushed into an empty orbital which is negative and then the positive end of the circuit attracts the electrons. As they go down in energy through the band gap, they emit light. The larger the band gap, the more energy, the smaller the wavelength and the closer to the "blue" end of the spectrum. So, the key is to try to control the band gap and thus control the color of light.
Food chemistry is an interesting and fun class for students. Read the article for some suggestions about resources along with an outline of a unit developed around water in cooking.
Fostering Creativity in Chemistry
The February 2017 online issue of the Journal of Chemical Education is now available to subscribers. Topics featured include: surface chemistry; chemical identity thinking; conceptual understanding; communicating science to the general public; activities and labs linking chemistry and art; history and chemistry; early access to research; technology as instructional support; synthesis laboratories; from the archives: bottle chemistry.
The chemistry of the Sky Blue dye found in McCormick's Color From Nature food colors is explored. This is part one of a three-part series in which the chemistry of McCormick's Color From Nature food colors is presented.
Students will build models of isomers while the instructor walks around from station to station to critique the models. If the model is incorrect, the students rebuild until they get it right. The paper that accompanies this assignment is very easy to grade.
one 50 minute class
The solution to Chemical Mystery #9: Liquid Nitrogen vs. Dry Ice is presented. Why does liquid nitrogen launch the bucket so much higher than dry ice and water?
A 2L soda pop bottle is filled about one-third full with either liquid nitrogen or solid carbon dioxide (dry ice) and water. The bottle is sealed and a plastic bucket is placed on top. Do you think the liquid nitrogen or dry ice and water will make the bucket go higher? Can you explain the results using chemistry?
Ringing in Volume 94
The January 2017 issue of the Journal of Chemical Education is now available online to subscribers. Topics featured in this issue include: NMR spectroscopy; examining assessment; inquiry-based practices; cost-effective instrumentation; miscibility demonstrations; innovative laboratory experiments; from the archives: lightsticks.
Show the kids an event. Have them develop a model. Have each kid draw and write about the model and force them to ask themselves if this model can explain the event. As a teacher, first say something nice about it and then look for their misconceptions and use this as a formative assessment. Combine the individual models with others. Slowly build a larger model and constantly ask if this really explains the event.
This is the first isotope activity I have tried where the students can look inside the model that resembled the atom and find information that reinforced what an isotope actually is. Furthermore, the quantitative data forced them to examine beliefs about different types of averages and what the numbers really mean.