'What we did' on Friday 18th February 2011Our main subject matter for the evening was 'PHYSICS & CHEMISTRY''
OPENING DEMONSTRATION EXPERIMENT - 'The Ivory Soap Trick'. If you unwrap a bar of Ivory Soap (only obtainable from USA), microwave it the soap will expand into a foam that is more than six times the size of the original bar.Firstly it is the only soap that 'floats' in water.
During the making of the soap, air has been 'whipped' into the soap and cannot be seen, but the microwave imparts energy into the soap,water and air molcules, causing them to move faster and further away from each other. The result is the soap puffs up. Other branss of soap don't contain as much whipped up air and simply melt in the microwave.
Ivory soap trick
MARSHMALLOW SWEETS - YES! we had to microwave a dozen of so, what lovely goo!
INTERACTIVE - physics - 3 volunteers each held a hair dryer directing the column of air vertical.
The reason the ping pong ball stays nicely inside the column of air produced by the hair dryer without shifting sideways is due to air pressure. The fast moving air from the hair dryer creates a column of lower air pressure, the surrounding higher air pressure forces the ping pong ball to stay inside this column, making it easy to move the hair dryer around without losing control of the ping pong ball
One of the children managed to balance 2 ping pong balls and a balloon all at once
Ping pong balls balanced in a column of air
INTERACTIVE - Each child was given a test tube, half filled with water with a touch of food colouring, then added a quantity of veg oil. The oil floats on the water, proving that oil and water do not mix. Shook the test tube but still the globules of oil floated to the top.
INTERACTIVE - We made 'GOO' - Simply mixing water with 500 grams of cornstarch.
When squzzed it becomes a liquid, when it stays still on your hand it becomes a solid.
The reason why the mixture of cornstarch and water is so weird is because of viscosity. Viscosity is nothing but the thickness of a liquid which resists it to flow.
More details here
INTERACTIVE - One of the group tables had some electrical test meters and a number of jars containing -tap water, tap and veg oil, veg oil, De-Ionised water, Vinegar, Vinegar and salt, vinegar and sugar. The two electrodes from the test meter we placed apart in each jar to see what liquid pased the electrical current. They oberved how far the needle measured the amount of electricity the liquid passed.
INTERACTIVE - Data is sent by Fibre Optic Cables into houses ie Virgin Media.
A simple experiement to show that light can 'bend'. Make a small pencil size hole near the bottom of a 2 litre empty plastic bottle. Darken the room, fill the bottle with water, shine a torch through from the other side of the hole and place your hand to 'catch' the water.
You will see the light reflecting on your hand. More detail see Bending Light
INTERACTIVE - extras... 'Buzz & Light' challenges, Plasma Globes, Hologram Chamber, Model Saturn V Rocket & Space Displays, Stereograms & lots more.
The February issue of 'making science cool' booklet was handed out, or if children absent the booklet was posted - click here to see pdf copy.
In all a fantastic evening for children and helpers
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