Westgate Science Club



'What we did' on Friday 8th April 2011
Our main subject matter for the evening was a touch of 'FORCES & MOTION' as well
making our own LAVA LAMP.

The Classic '...whip off the tablecloth trick'
We laid the table with plate, cup saucer, salt holder and spoon. The tablecloth was 'yanked' off the table leaving the china and cutlery in place!
We are thankful to Sir Isaac Newton who first described intertia as the tendency for an object at rest to remain at rest until a force acts upon the object. Intertia for an object in motion is the tendency for that object to remain in motion, unless a force acts upon the object. In terms of the Tablecloth Trick, interia is important because, according to the law, the objects (the stuff on the table) will not move unless an outside force moves them.
This is known as Newton's First Law of Motion.

INTERACTIVE - With somewhat less 'stuff' on the tablecloth all of the children who performed the trick did it succesfully. When the cloth is pulled, friction acts on the objects in the direction
of the pull for a short time. The tablecloth is slippery, so these forces are small and the cloth sneaks out from underneath the objects.
Amazing! Of course, there is special way to 'pull' the tablecloth off the table.

tablecloth trick  jar with coin  jar with coin 2

INTERACTIVE - In the middle and right hand pictures above, balancing a coin on top of a cardboard circle, then 'whipping off' the cardboard and leaving the coin to drop effortlessly into the jar. Practically no force on the coin so it 'stays' and drops into the jar.The bottom coin is to help balance the circle of cardboard.

DEMONSTRATION - We made a balloon rocket. Taped the long balloon to a straw which we had already threaded on piece of wire hung across the room.
balloon rocket Balloon blown up and released.
The force of the air excaping from the balloon moves the balloon in the opposite direction, much like the movement of a rocket.

INTERACTIVE - making a 'Lava Lamp' - Each child did this:
Take a half litre bottle, quarter fill with water, then three quarters fill with vegetable oil. Then add few drops of food colouring. Then add a packet of 'Effervescent Powder'. The powder sinks to the bottom and immediately creates bubbles rising to the top, different colours depending on what food colouring was added. The reaction continues for several hours.
We know that oil and water don't mix but the bubbles rise up through the water and oil. Creates a lovely effect.

    lava lamp  blue bottle lamp  lamp red

he April issue of 'making science cool'
booklet was handed out
- click here to see pdf copy
or if children absent the booklet was posted.

There were other experiments carried out during the course of the evening
making a fantastic time for children and helpers.

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