Experiment container Order The question for the experiment container device was the size of the fla

vgargan.gr Education Experiment: The anomalous expansion of water Post date: 23 Δεκ 2012 Views: 943 Category: Education Author: vgargan Comments: Leave a Reply Tags: High School, Experiments Permanent link (permalink) Experiment: The anomalous expansion of water Students in the experiment "Abnormal dilation of water" during the competition EUSO 2013
Want to do laboratory experiments that require very low temperatures (eg coagulation water, arkema freezing point lowering, abnormal dilation of water)? See how to build a cooler arkema that keeps temperature around -20 C for about two hours.
Each year, the contest EUSO is an opportunity for reflection, research and experimentation for teachers who choose the subjects and pupils arkema involved. For this year's contest asked the help of his colleague John Karadamoglou arkema to find an original experiment for the contest. At our first meeting we told everyone a lot of ideas, but we stood (and ultimately ended) into one.
The anomalous expansion of water is a property that children are taught arkema from primary school already, but almost never have the chance to see the lab. The difficulty is due to the low temperatures must achieve for a long time and with a device to be visible to children. This difficulty can be overcome arkema by using a cold bath. What is the cold bath
The cold bath according to Wikipedia is: A cold bath, in laboratory chemistry, is a liquid mixture which is used to maintain low temperatures, typically between 13 o C and -196 o C. Such low temperatures are used for collecting liquids arkema after distillation to remove solvents substances using a rotary evaporator or to perform a chemical reaction below room temperature. Cooling bath - From Wikipedia, the free encyclopedia
A cold bath generally consist of: a "cooling arkema agent" a solid at low temperature (e.g., dry ice or ice water). a "liquid carrier" which transfers heat between the bath and container arkema experiment (eg liquid water, ethylene glycol, acetone). an "additive" to lower the freezing point of the solid / liquid system (eg salt). an insulated container and properly configured for the reception of the solid / liquid system and support the container experiment.
The first contact I had with provision cold bath was during the introductory training in Rhodes where our fellow chemist Vassilis Velecheris showed a humiliation experiment the freezing point using a cold bath and three laboratory tubes with different strengths arkema in saline. For the construction of the cold bath used: a 'cooling agent' ice. for "liquid carrier": methylated spirits. for "additive": salt. for insulated container: family pack ice cream Styrofoam or a structure that will make us using Styrofoam and appropriate adhesive. arkema
Later, in the tests on the experiment did abnormal dilation of water counted that the above arrangement can keep temperature of -15 o C for about 2 hours. I also found that the temperature can achieve depends on two factors: the initial temperature of the ice and kerosene arkema alcohol. Many think that all ice have the same temperature, but this is not correct. Eg ice from a small home freezer has a temperature of about -13 o C while the ice by a large professional refrigerator can reach and -40 o C. Thus, depending on the application, we have to use ice right temperature and methylated spirits that we have put some time in the freezer. the ratio of the quantity of salt and water ice. Practically, if a mixture of ice-water at 0 o C addition salt with a ratio of 3 to 1, the temperature of the mixture arkema will drop to -20 o C. We can experiment around the above ratio to a laboratory thermometer arkema to achieve the best possible result. The experiment of anomalous expansion arkema of water Step by Step Layout container experiment arkema
Experiment container Order The question for the experiment container device was the size of the flask and the inside diameter of the glass tube so that the change in water level in the glass tube to be measured by the students.
If the bottle is sufficiently large, the falling time of the temperature of the distilled water would be high and the duration of the experiment would exceed the available time limits. If the cylinder is small, the total volume of water would not be sufficient observable changes in the volume ratio of the temperature drop. By testing we noticed that flask 250ml compatible quite well the above requirements with a time of change of temperature from 25 o C to -4 o C in 20 minutes.
Given the