Tuesday, 24 March 2009

Extinction a candle

video

Materials needed: a glass -vinegar -sodium bicarbonate a candle lit The working In a glass place vinegar (3-4cm). Add a spoon of sodium bicarbonate. The two substances produce a reaction. Expected to leave the foam obtained. Meanwhile, light a candle, then take the glass with vinegar and bicarbonate and we approach the candle not let the liquid fall to the flame. Explanation: Candle is extinguished due to gas produced by the two

Tritean Elena, Nichilciuc Claudia

Scoala Gimnaziala "Gheorghe Lazar" Zalau (Romania)

Water pressure

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Horea H, Andrei M

Scoala Gimnaziala "Gheorghe Lazar" Zalau (Romania)

Hot air, cold air

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Horea H, Andrei M

Scoala Gimnaziala "Gheorghe Lazar" Zalau (Romania)

Ballon not exploding

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Oroles Jidav, Lavinia Pop, Aurelia Campean, Vlad Drulea

Scoala Gimnaziala "Gheorghe Lazar" Zalau (Romania)

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Vlad si Alex

Scoala Gimnaziala "Gheorghe Lazar" Zalau (Romania)

Friday, 20 March 2009

The descomposition of oxigenated water

Materials:

- Oxigenated water
- Blood
- Some matches
- A glass

To realice our experiment we need oxygenated water (of sale in drugstores) and a few milliliters of blood. If we defrost a piece of meat in a plate, we can obtain sufficient blood to realize our experiment.

We add blood to a glass with oxygenated water and see that a chemical reaction takes place with gass emission that forms a white foam. The oxygenated water descomposes, due to blood, in water and gaseous oxygen (that forms the white foam). We can recognize the oxygen if we bring a match over.

You can see that the sparkles of light take place due to the combustion of the oxygen caught in the white foam.

The oxygenated water is used as disinfectatn when it begins on a wound. The blood contains one enzyme that acts as a catalyst, accelerating the reaction descomposition of the oxygenated water. As many of the pathogenic bacteria are anaerobic (they can´t live with oxygen), they die in the white foam (rich in oxygen) that takes place when the blood of the wound acts on the oxygenated water.




Thursday, 19 March 2009

Sunday, 15 March 2009

The Colour of Fire

Group 8 - Liana R, Andrada S, Alexandru S, Octavian L, Darius O - Colegiul Naţional "Mihai Eminescu" Satu Mare, România

Materials used: filter paper, tong, Berzelius glass, a spirit lamp, matches, chemical substances: SrCl2, CuSO4, KClO3

First we prepared solutions dissolving the substances from above in water. We put a filter paper in each solution and then we let them dry for about two days. Then, with the tongs, we put each filter paper above the spirit lamp and the flames burned with different colours.

Tuesday, 10 March 2009

Another balance with two forks a toothpick and fire

To make the experiment we need two forks, a toothpick, a glass and a few matches.

We entwine both forks with the toothpick and leave the set in balance in the edge of a glass. The balance is achieved when the gravity center of the set is below the point of support.

What does happen if we burn the end of the toothpick that is inside the glass?

A part of the toothpick burns but the flame goes out when coming at the edge of the glass and the balance of the forks is kept. The loss of mass of the toothpick that has burnt not affect significantly the gravity center that continues below the point of support.


By Inma and Pía

Resonnance in wine Glasses

MATERIALS

To make a wine glass sing, you will need the following materials:

1. Wine glass - a crystal, thin-walled one works best.
2. Separate glass or jug
3. Water

PROCEDURE

To make the wine glass sing, do the following:

1. Fill the empty glass or jug with water.
2. Add the water to the wine glass
3. Wet the index or middle finger of your hand with some water.
4. Lightly rub your wet finger along the rim of the glass.
5. As you rub the glass, you will hear the "singing" sound of the glass. You may have to re-wet your finger periodically and/or adjust the pressure of your finger on the rim of the glass to keep producing the sound.
6. You can change the pitch of the sound by adding water to the glass.

EXPLANATION

Every material (such as glass, steel…) has a natural frequency at which it vibrates, called a resonant frequency. Resonance is a physical phenomenon that occurs when a body is capable of vibrating under the action of a regular force. Its period of vibration coincides with the period of vibration characteristic of that body. In these circumstances, the body vibrates increasing gradually the amplitude of vibration after each of the subsequent actions of the force.
The cup vibrates with a determinate frequency and tone. If more water is added to the wine glass the tone becomes lower.



by Mª del Mar y Blanca

Monday, 9 March 2009

Sunday, 8 March 2009

The backwash of colours

Main objective of lab: To see how the surface tension causes the food colourings to swirl in the saucer.

Materials used
Milk*Food colouring (4 colours) *A saucer *
The backwash of colours (Vartej de culori): Add a drop of each colour to the*Fill the saucer with milk *Detergent Methods: Add one drop of detergent to the center of the saucer
Results: The colours milk swirl in the saucer

Medina B., Bogdan D , Scoala Gimnaziala "Gheorghe Lazar" Zalau,Romania

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Thursday, 5 March 2009

Atmospheric pressure

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To perform this experiment we need a boiled egg, bark, matches and a bottle with his mouth wider. First light match, is inserted in the bottle and let them burn. Bark boiled egg and place over the mouth of the bottle. After put the eggs, match is extinguished, and the eggs begin to pass the mouth of the bottle until it reaches the. Because the eggs covered the mouth of the glass to match the fire consumed all the oxygen in the bottle, and after it was extinguished. Explanation: Because of the lack of oxygen pressure and body weight decreases with pressure acting on the outside glass egg that "leaking" through the mouth bottles.

Breje Diana, Festeu Cristina, Hara Paula, Vidrasan Emanuela

Scoala Gimnaziala "Gheorghe Lazar" Zalau, Romania

Snake chimical

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Solution of silver nitrate; copper wire

Tuesday, 3 March 2009

A ball that floats

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Materials: To make our experiment we need a light ball ping-pong and a hairdryer. Uscătorul start and leave the ball in the air. Depending on the weight of the ball remains suspended it closer or further away from dryer.
Explanation phenomenon that took place: The explanation seems simple experiment. Upward flow of air from the dryer generates a pressure force which compensates the weight of the ball. This allows the ball float in the air.
Observations:
The speed of air leaving the dryer increases in the central and lower edges. In regions where the air is moving with greater speed and low pressure, and regions where the air has a lower speed is high pressure. When the ball is moved slightly from the central part of the current, generates a difference in pressure pushes the ball back to the center of power.

Bora Dan, Puscas Lavinia, Marincas Matei, Breje Georgeta

Scoala Gimnaziala "Gheorghe Lazar", Zalau, Romania

Colored Smoke

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Materials used (to smoke one): - 8g K (NO3) - 6G sugar- 3g of food coloring, powder (use more colors) - 1.5 g of sodium bicarbonate - Source of heat (gas, electric furnace, etc.). - Container for mixing ingredients, resistant to high temperatures, metal (pan, vessel of metal, etc.). - A spoon (or something for. Mixed metal) - Small cardboard tube (diameter approx. 1.25 cm and 2 cm) and a switch to plastic - Lint (from fireworks, ca. 2.5 cm) - Little plastelină

Method of preparation: - Mix the following ingredients: -K (NO3), sugar, color and bicarbonated sodium - The substance is produced in a pan - Put the pan into the fire, and mix until the substance becomes omogenizează as peanut butter (be careful not to become too dark in color) - The substance is obtained with the spoon and put in the cardboard tube in the middle of his stick, until about the middle height tube, beţişorul plastic and leave it so until the mixture strengthens after strengthening to remove, carefully beţişorul - In the hole left by the switch fuse is inserted and in addition it put plastelină the cardboard tube removed, using a knife, with great care * smoke obtained is placed on a heat resistant material * light the fuse and see a spectacular game of colors and lights WARNING: during the whole experiment will wear protective equipment and heating the ingredients will not be made in cash or in any room!

Bode Bianca , Lascu Iulia , Gudea Casian

Scoala Gimnaziala "Gheorghe Lazar" Zalau, Romania

Oxidation of apples

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Materials: An apple A lamiae A transparent foil Ice Four plates
Working mode: Cut four pieces of apples. In each plate by putting a piece of apple. During the first plate put a simple piece of March In the second plate put a piece of March infoliata In the third plate put another piece of March over the add lemon juice In the last dish put a piece of ice in March Shot in ten in ten minutes, and at last, after thirty minutes are stage four pieces of apples.
Observations: After each 10-minute video and I noticed that the apples are oxidised gradually, Whether the materials used. After thirty minutes I noticed that the piece of oxidised Tuesday is simple.
Explanation phenomenon that took place:Oxidation is a chemical reaction that occurs Marului contact with oxygen in the air. In our experiment can be seen easily as color becomes more closed to supraafata contact. Apples oxidation can be delayed with ice and a transparent foil so that the apples do not come into contact with oxygen. Another method to retard oxidation is to add a little lemon juice. Lemon juice contains vitamin C which acts as an antioxidant. Therefore in many restaurants salatele fruit containing a little lemon juice to help not rust.
Conclusions: For this experiment we concluded that apples should be cut not left much time in direct contact with oxygen (02).

Puscas Lavinia , BoraDan , Marincas Matei ,Breje Georgeta , Pah Dana, Pop Giorgiana, Rus Raluca, Turcas AlexandraScoala Gimnaziala Gheorghe Lazar", Zalau, Romania

Condensation in glass

video

To make our experiment we need a plastic bottle of 1.5 liters, a sheet of paper and some matches. First is a pair of holes in the plastic bottle at the beginning and another near the glass. Then take the sheet and cut a rectangle of 10x15 cm. Roll of paper for a small cylinder about 15 cm long. Finally the tube is inserted through a hole above the paper bottle. When you turn on the tube of paper with a match is made and a small flame is observed, on the other end of the tube leaving a dense column of smoke, falling into the bottle. On the outside, no smoke. If you cover the bottom hole with a finger to see how the smoke comes out next paper. Explanation: By burning the tube portion of the paper is apparent in the form of particles with gases that are formed during combustion and the air is smoky. Under normal circumstances, the smoke is drawn to the burning hot air (convection currents) In our experiment, the smoke that is produced inside the tube along its journey. Inside the bottle is not hot air, so that when smoke comes out the bottom end of the tube there is no convection and upwelling of smoke (more dense than air) precipitates at the bottom of the bottle.

Barnutiu S, Blaga A, Gaidos C, Chira F, Temes C

Scoala Gimnaziala "Gheorghe Lazar" , Zalau, Romania

Action on the spirit egg

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Materials; A plate of iron A fresh-egg A bottle of alcohol The working Put the tray in spirit, not too much, then break the eggs and we put in tray and let alcohol act Observations after 10 minutes to observe the effect of alcohol and gets the eggs begin to albeasca. After 30 minutes, the eggs start easy, easy to prajeasca, and after 45 minutes is totally fried. Explaining the phenomenon Egg is a food product after contact with spirits (flammable liquid), the eggs begin to prajeasca like when fried in oil. Conclusions Depending on the method applied I noticed that the eggs can be fried in alcohol without having contact with fire.

Pop Georgiana, Turcas Alexandra, Pah Dana, Rus Raluca

Scoala Gimnaziala "Gheorghe Lazar", Zalau, Romania

Action of vinegar on the shell egg

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Materials - 1 egg -200 Ml vinegar (acetic acid) -1 Bol The working Put the eggs in vinegar in bol, after which the liquid drop in 24 hours Observations After several hours we see how the shell egg is inmoaie Later Note how the shell away from the egg, floating on the surface of liquid Finally, the remaining egg shell burst, reaching in egg yolk vinegar Explanation phenomenon that occurred Vinegar, a food, is an acid that acts on calcium carbonate from egg shell. Because decomposing shell egg is back, finally arriving in egg yolk vinegar.


Georgiana P, Alexandra T, Dana P, RalucaR

Scoala Gimnaziala "Gheorghe Lazar" Zalau, Romania

Vulcan Chemical

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To build it you need: 100 g-flour, 5 tablespoons aracet-50-g salt, 6 newspapers. 1.Mai first newspapers to break in pieces and then put them in a bucket 2.Puneti water from newspapers to fill the dish and a towel covering them. 3.Le left soaking in a night. 4.Pe boards of a size of A3 sheets paste a bottle. 500ml cut at the top. 5.a day they stoarceti water and make a composition that will stick. 6 After composition, begin to build up near the glass ii dati a suitable form.

Hudin Horatiu; Margin Horea ;Trestian Vlad;Negrea Sebastian;Margin Ionut

Scoala Gimnaziala "Gheorghe Lazar" , Zalau,Romania

Vulcan Chemical_Eruption

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Eruption: the glass in place until the half. vinegar and bicarbonate food. To get lava you can use colored or red coloring yellow.

Warning! Do not make rash supervised by the teacher!

Hudin Horatiu; Margin Horea ; Trestian Vlad; Negrea Sebastian; Margin Ionut

Scoala Gimnaziala "Gheorghe Lazar" , Zalau, Romania