Elena Moreno Gómez de Barreda Academie year 2010-2011
Technical and physical phenomena 3
Experiment: floating and sinking.
# Question: What will happen if you put an egg in a glass of water? And what will happen if we put an egg in a glass of water with salt?
# Hypothesis: You have to write here, that you think will happen with each egg.
#Experiment: For do the experiment you have to do... **You need: 3 big glasses, one egg, water and salt. 1. Fill two glasses of water. 2. Throw in one of them salt gradually. Stirring with a spoon, try to dissolve as much as possible. 3. Place the egg in the glass that has only water. 4. Now, put it in the glass in which you have dissolved the salt. 5. In the third glass, put the egg and water until itcovers and a little more. Add water with salt, you already have, until you get the eggs are on the fence (neither floats nor sinks). 6. Now, you add at this time a little water, then add a little salt water, again add water and so on.
# Result: The egg is intoduce in the glass of water, will sink. The egg is inserted into the glass of salt water will float. In the third glass, the egg will staybetween the two waters. if you enter after salt water will float, if you go to get water without salt, it will sink and so on.
# Scientific explanation: On the egg, two forces act, their weight (the force which pulls the Earth) and the thrust (the force that makes up water.) If the weight is greater than the push, the egg sinks. Otherwise fleet and if they are equal, it is between two stools.The drive gets a body in a fluid depends on three factors: • • • Liquid density The volume of the body is immersed Gravity
Adding salt to the water, get a liquid denser than pure water, which makes the drive gets the egg is larger and exceeds the weight of the egg: the egg floats.
# Question: In this experiement going to ride a circuit to see what materials are goodconductors of electricity and what not. For them we will build an electric circuit, and test if it passes the power of various elements such as a spoon, a string, a pencil, a pen, ...
# Hypothesis: You have to write here, with which elements you think the electricity can pass and are good conductors, and which aren´t good.
# Experiment: For do the experiment you have to do... **You need: foreach group will need a normal battery of 4.5 volts, a small light bulb, three wires and various objects like scissors, a spoon, rope, wire, nails, pencil, foil, etc. Switch the battery and the bulb as shown in the picture. Then you prove each of the objects you have.
# Result: The bulb will light up every time we use a metal object, gold, silver, copper, lead, ... And do not light upwhen we place some wood, plastic, ceramic ...
#Scientific explanation: Drivers are all those materials or elements that allow cross the stream flow or moving electric charges. If the bulb lights mean that the material used is a good conductor of electricity. Those with the bulb does not light are insulators.
# Question: Build a compass in class.
# Hypothesis: You haveto write here, what do you think if you build a compass. How does it work? what use is it?
# Experiment: **You need: A needle, a magnet and a piece of thread. • • Rub the magnetic needle always in the same direction. Tie the string in the middle of the needle and let it hang.
# Result: The needle will always be in the same direction, pointing the North.
# Scientific explanation: When wehang the magnet by a thread, said magnet marks the earth's magnetic poles. These poles are related to the geographic poles we know. Thus the magnet marks the north of the land. The compass has a magnet inside that spins freely, and that shows us the same magnet north and south. In this way we also know where the east and west. Therefore, the compasses are useful to guide anywhere on earth....