Site powered by Webvision Cloud. Skip to main content Skip to navigation. No comments. Download all. Additional information If you teach primary science, see the headings below to find out how to use this resource: Skill development Children will develop their working scientifically skills by: Drawing conclusions and raising further questions that could be investigated, based on their data and observations.
Using appropriate scientific language and ideas to explain, evaluate and communicate their findings. Asking their own questions about scientific phenomena. Learning outcomes Children will: Observe that some materials will dissolve in liquid to form a solution, and describe how to recover a substance from a solution.
Explain that some changes result in the formation of new materials, and that this kind of change is not usually reversible, including changes associated with burning and the action of acid on bicarbonate of soda. Concepts supported Children will learn: Substances can be grouped according to their chemical and physical properties, including dissolving. Suggested activity use This activity could be carried out as a whole class investigation, with children working in small groups to solve the problem.
Practical considerations Primary schools may have limited resources, so you may want to adapt the original letter and activity to meet your needs. Hydrochloric acid cannot be used with young children, so vinegar could be an alternative.
Level years years. Use Practical experiments Download. Design, plan and conduct investigations; explain how reliability, accuracy, precision, fairness, safety, ethics, and the selection of suitable equipment have been considered. Review and reflect on the skills and thinking used in carrying out investigations, and apply their learning and skills to solving problems in unfamiliar contexts.
Chemical world Energy 9. This depends on whether the photon hitting it has sufficient energy i. Once an electron is kicked up an energy level it really wants to move back down to its chill ground state, by losing energy in the form of a photon. Through a series of steps, the molecule emits a photon of a single wavelength. If the photon possesses a wavelength that falls within the visible region, we see this as color. White powders look white because when light hits these molecules, they are scattered at all angles without being absorbed.
In crystal lattices, this light simply passes through — again without being absorbed — rendering them transparent instead of white. For a compound to possess color, some form of light absorption must occur. Hang on, so if I decrease this energy gap and therefore the energy required to excite electrons, maybe visible light could excite my compound?
A way to reduce the energy is to introduce double bonds; double bond electron orbitals are higher in energy than their single bonds counterparts. Even better would be to conjugate these double bonds so that they absorb energy at an even higher wavelength. You could also make your compound very big. How does this work? With small organic molecules, E is high because L is small. To put it simply: mashing many orbitals together by increasing the size of a molecule will lower the overall energy, allowing the highest energy electron to transition more easily!
Indeed, many dyes that we use today are structured both conjugated and large, meaning that visible light is enough to make them show off their pretty colors. While organic chemistry mostly deals with smaller elements such as carbon and nitrogen, transition metals are much larger and contain more electrons. When an envelope in a mail terminal in Stokke, south of Oslo, burst and released a cloud of white powder, it had serious, unnerving consequences. Several employees reported burning, itchy skin and difficulty breathing, according to an article about the incident in a national newspaper, VG.
The mail terminal was closed and evacuated, and all told, 44 people were sent to the hospital. While white powder in a package or letter may be completely harmless, sometimes it is not. In , letters filled with deadly anthrax bacteria were sent to US senators and media companies.
Five people died and 17 people were injured in the attack. Luckily, it turned out to be a harmless flour product that someone had mailed. The police will now investigate the case, according to Aftenposten, an Oslo-based national newspaper.
But how do scientists actually figure out what is in mysterious, suspicious powders? The Norwegian Defence Research Establishment actually has four different laboratories, each of which has a specific focus on explosives, or biological, chemical or radioactive substances.
By the time they get an unknown substance to be tested, they have already received some information about the sample from the people or institution that submitted it. It is important for FFI researchers to know what is happening to people who might have been exposed to the unknown substance.
If the substance contains infectious agents, it may take hours before people feel ill, while dangerous chemical substances may cause more acute injuries. They must also treat the substance as if it were contagious or dangerous until they know more about it.
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