The abstractness of certain chemistry concepts demands the use of appropriate teaching strategies to enable students to construct mental images of the concepts. The concepts include understanding the effects of concentration and catalyst on the rate of reaction. The reactions at the molecular level are not visible to human eyes and the use of…

Portuguese schools hold important collections, most organised in the late nineteenth and early twentieth centuries. This scientific heritage, however, is still to be discovered. This article focuses on the creation, development, and role of natural history collections in Portuguese secondary schools, between the second half of the nineteenth…

SenseCube is a multisensor capable of measuring many different real-time events and changes in environment. Most conventional sensors used in introductory-physics labs use their own software and have wires that must be attached to a computer or an alternate device to analyze the data. This makes the standard sensors time consuming, tedious, and…

The ability of certain organometallic reagents to react via 1,2- or 1,4-addition to an a,ß-unsaturated ketone is a fundamental example of regioselectivity at the second-year undergraduate organic level. The following two experiments were designed to demonstrate this preference by exploiting carvone as an inexpensive chiral, nonracemic substrate.…

Practicing chemists use models, diagrams, symbols, and figures to represent phenomena which cannot be detected by the human senses. Although research suggests that these external representations (ERs) can also be used to address the challenges that students have in learning chemistry, it is not clear how instructors' use of ERs aligns with their…

A simple synthesis of fluorescent carbon quantum dots from lemon juice is described to introduce advanced high-school students and undergraduate college students to nanoparticle synthesis and quantum dots. The synthesis is based on the carbonization of lemon juice using only a hot plate stirrer. Column chromatography is used to separate different…

As a fundamental part of their chemical education, first-year undergraduate students are substantially involved in laboratory activities. Despite the specific teaching staff choices on the main laboratory aims, students normally receive a vast amount of information during these activities. Apart from understanding theoretical content, fundamental…

Engaging undergraduates in the environmental consequences of fossil fuel usage primes them to consider their own anthropogenic impact, and the benefits and trade-offs of converting to renewable fuel strategies. This laboratory activity explores the potential contaminants (both inorganic and organic) present in the raw fuel and solid waste…

Samples of a composite hydrogel incorporating clay (Laponite XLG and S-482) nanoparticles were prepared using N-isopropylacrylamide. The hydrogels were formed via a radical-initiated addition polymerization using potassium persulfate and N,N,N',N'-tetramethylethylenediamine. Students then measured the force required to stretch the gels and…

In an effort to repurpose expired guaifenesin tablets, experiments devised for practical instruction are reported for the preparation and isolation of the guaifenesin acetonide using a microscale kit. The laboratory experiment successfully utilizes a waste chemical in lieu of a fine chemical to illustrate the principles behind protecting groups in…

Enzymatic activity is at the core of biological reactions. Understanding them and the chemical and environmental factors that affect reaction rates is critical for biology students. The laboratory experiment proposed here investigated these concepts, while requiring students to document, graph data, analyse results using statistics, and…

The laboratory instruction sheet (sometimes called a laboratory manual), together with the equipment used by students, is an essential resource for laboratory work. It has a direct influence over all the interactions that can occur in the laboratory activity, of which student-equipment is the only common synchronous interaction in both…

In the course of PISA and TIMSS a lot of out-of-school lab days have been established; as non-formal extracurricular learning environments they shall provide an efficient addition to formal learning at school. The "ELKE" project is a non-formal extracurricular learning lab that aims at linking curricular content and competence-centred…

Past studies on the differential effects of active learning based on students' prior preparation and knowledge have been mixed. The purpose of the present study was to ask whether students with different levels of prior preparation responded differently to laboratory courses in which a guided-inquiry module was implemented. In the first study, we…

The practice of RNA isolation in undergraduate experimental courses is rare because of the existence of robust, ubiquitous and stable ribonucleases. We reported here modifications to our original protocol for RNA isolation from plant tissues, including the recovery of nucleic acids by ethanol precipitation at 0 degrees C for 10 min and the…