Experimental Sciences

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Measuring an Equilibrium Constant through Titration

In order to understand how a system achieves equilibrium, we need to measure the concentration of reactants and products of a chemical reaction. To do this, IBDP Chemistry Grade 12 students used a common laboratory method known as Titration.

For this experiment, the following reversible chemical reaction was investigated:

Ethanol + Ethanoic Acid  Ethyl Ethanoate + Water

The picture shows the chemicals used for the experiment: Ethanol, Ethyl Ethanoate, Hydrochloric Acid and Water

The picture shows the chemicals used for the experiment: Ethanol, Ethyl Ethanoate, Hydrochloric Acid and Water

The picture above shows liquids being measured out from a burette.  The boiling tubes were stoppered as soon as the needed amounts of liquids were transferred into them.

The picture above shows liquids being measured out from a burette.  The boiling tubes were stoppered as soon as the needed amounts of liquids were transferred into them.

Student made sure to stopper all boiling tubes to prevent evaporation of the liquids inside

Student made sure to stopper all boiling tubes to prevent evaporation of the liquids inside

Through titration, it is possible to get the concentration of the reactants (ethanol, ethanoic acid) and products (ethyl ethanoate, water) by using an acid to catalyze the reaction. In the case of the experiment, a common acid, known as hydrochloric acid was used.

Student using NaOH as the titrant to measure the concentration of the liquids in the erlenmeyer flasks.

Student using NaOH as the titrant to measure the concentration of the liquids in the erlenmeyer flasks.

However, the reaction of ethanol and ethanoic acid, even with the aid of a catalyst was very slow.  It took the students approximately a whole week to finish the experiment.

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The “Visking” Tubing Experiment

The human body is a complex system that consists of varying organ structures working and indefatigably functioning in sync together to maintain equilibrium, thus, to sustain life.

IB DP Year 2 students took their first on-hand experiment on digestion, called “Visking Tubing Experiment”. One of the best ways to learn and understand the processes that take place in the body is by modelling. This experiment provides a visual way of demonstrating diffusion through a semi-permeable membrane. It was used to model the human gut as well as to investigate the effect of the enzyme called amylase on starch. Two standard macro molecules tests were done. The first test done is called the Iodine Test. It is done to determine the presence of starch in certain foods or substance. The second test done was the Benedict’s test, which is used to test for the presence of reducing sugars, such as glucose.

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The Visking Tubing Experiment set-up

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Benedict’s solution, used to test for the reducing or simple sugars.

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All samples were taken and were submerged in hot water bath. Benedict’s reagent starts out aqua-blue in color. As it is heated in the presence of reducing sugars, it turns yellow, green, orange or brick-red. The final color of the reagent signifies the concentration of reducing sugar. Brick red signifies a high concentration of glucose.

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Iodine solution

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Iodine solution, used to test for starch. A blue-black color results if starch is present. Otherwise, the original brown color will will be retained.

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G7 Artisan Soap Project

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Grade 7 enjoyed making their soap project in Chemistry as one of their final requirement for the 3rd Quarter.
They were able to make use of their skills in proper handling of laboratory apparatus and as well as practice safety in the lab while working on their soap project. They used different prcesses in creating and improving their product such as melting, freezing, purifying as well as using methods to avoid contamination of bacteria. Using an existing organic soap base the class which was devided in 2 groups were able to make different variants . They used organic ingredients such as flowers, oats, cinamon etc.. and researched on the additional health benefits when added to their soap product. The class enjoyed working with their groups and collaborating their ideas.

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G7 while presenting their Soap Project to the Class

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Finding Evidence of Chemical Reaction

Grade 10 is learning about the evidences of chemical reaction in this experiment they will recognize that formation of precipitate is a result of chemical reaction. They used different compounds in the laboratory and experimented on the reactions of each when mixed.at the end of the the experiment as part of post-lab discussion they were able to identify mixed compounds that undergo chemical reaction.
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Interactive System Models

Gr.10 students created interactive system models as a summative assessment for the subject Systems  Design and Societies.

One of the groups made a model for Water Cycle, the other group prepared a model for the Human Digestive System while the third group created the Urinary System model.

The fourth group created a model of the Human reproductive systems. It showcases how the sperm cells approach the mature egg cell in the fallopian tube. In this model, the students used Hot wheel toy cars and its tracks to simulate sperm movement.

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Genetic Offspring Models

Problem: Based on the genotype and phenotype of the
parents, can you design a model of the offspring?

Gr.7 students chose chromosome pairs (one from each
“bug” parent) with specific genotype and phenotype.
Students created models of bug offspring using the
known traits of its parents.

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Modeling Mendel: Predicting the Outcome of Genetic Crosses

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Gr.7 students were able to predict the traits (phenotype) of offspring from parents whose genetic composition (genotype) is known. Students also demonstrated the difference between dominant and recessive alleles. This activity visually introduced the terms used in Punnett Squares.

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Learning Mixture

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Grade 6JL Having fun playing the role of a Scientist :)

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G6JL is learning about separation of mixture as part of their lesson in Classification of Matter. They move from one station to the other to observe different ways on how components of a mixture could be separated using methods such as evaporation, scooping, chromatography, decantation and filtration.

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Skype a Scientist

Last Wednesday, November 29, 2017 grade 6JL and grade 6GT had the chance to experience talking with a real scientist via skype. He is Mr Jeffrey Schwartz, nanophysicist working with Interpol and University of California. Everyone had the chance to ask questions from the challenges faced by a scientist to atom related questions and inventions. Organized by Ms. Madhumita Saini. It was truly a fun experience for the kids who aspires to be a scientist.

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Grade 6JL learned about the evidences of Chemical Change. The class were divided into 2 groups, baked cookies using their own recipe and were able to identify the changes that happened to the batter after baking in which they considered as evidences for Chemical Change.Each group asked some faculty members to evaluate their cookie which made the activity more fun.

  • http://www.deped.gov.ph/