Home Experiments

Title: Vacuum Using Candle and Glass

Chemicals: water
Equipment:bowl, candle, lighter, 2 glasses
Procedure: First, add enough water to fill the bottom of the plate. Light the candle. Place the candle in the middle of the plate. Take the glass and place it over the lit candle.

Results:
1.The water level inside the glass rises
2.The candle is extinguished

Conclusion: The water level inside the glass rises because the burning candle heats the air inside the glass.The air inside the glass now has a higher pressure than the air outside the glass. The higher pressure of the air outside the glass pushes down on the water in the bowl and forces it up into the glass. The candle is extinguished
because of the vacuum in the glass.

Title: Pepper and Detergent
Chemicals: water,detergent
Equipment:pepper, bowl
Procedure: Pour enough water into a plate. Sprinkle fine ground black pepper on the water. Take a drop of detergent and put it in the middle of the plate.

Result : As the soap moves into the water, and the surface tension changes, the pepper no longer floats on top.

Conclusion:Pepper is hydrophobic,that means that water is not attracted to it. Because of that, pepper can’t dissolve in the water. Soap is able to break down the surface tension of water. As the soap moves into the water, and the surface tension changes, the pepper no longer floats on top.

Student A (the one in the video): Valeria Marjanović
Student B (the one who filmed the experiment): Magdalena Ondrušek
Student C (the one who uploaded the video): Nevena Mitić
Student D (the one who wrote description): Nina Novosel
Student E : Damir Jakus
Experiment was made by students attending Beginner English at Faculty of Chemical Engineering and Technology, University of Zagreb. Lecturer is Nadja Dešpalj.

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