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Welcome to Tuesday of Science Week! I hope you enjoyed watching and investigating the experiments yesterday. Have you tried any yet? All of our experiments today are investigating different aspects of Physics.
Today one of our experiments involves force and load - testing how much weight (or MASS) a spaghetti bridge can hold before it breaks...
Another experiment investigates static electricity - how to generate some and how to use it to separate salt and pepper on a plate...
Our last experiment today involves density - how much space a particular object takes up - its VOLUME, and how much 'stuff' or MATTER there is in that volume - its MASS. When we talk about how heavy things are and compare them, we are really talking about how much MASS these objects have. When we add in their VOLUME - how much space that particular mass takes up - we are talking about density.
Some objects can be very small in volume but can have lots of mass, for example, some metals such as iron or steel. Other objects can take up a lot of space but are very light, having little mass, for example, a balloon. In this experiment today we will be investigating the density of raisins by placing them in different liquids. Can we use carbon dioxide bubbles to help the raisins float instead of sink...? I wonder....
Equipment needed for various physics experiments today:
dried spaghetti
paper clip
disposable paper or plastic cup
test weights such as coins (I used 10c pieces), marbles, small rocks of similar size and weight etc
2 glasses or containers of same height
kitchen scales (optional)
plastic spoon
salt and pepper
plate
various surfaces on which to generate static electricity, eg. hair, clothes, carpet, balloons, blankets etc.
raisins (or other dried fruit)
clear carbonated liquids, like mineral water or soda water or lemonade
bicarbonate soda
vinegar
a clear glass for each liquid you use
Spaghetti Suspension Bridge
Have you ever wondered how bridges can support lots of cars and trucks driving across them without falling down? Well, today you are going to create your own spaghetti suspension bridge and keep adding weight to it until the spaghetti breaks! Your task is to be an engineer and test how much 'load' or force your bridge can take before it will 'collapse' or break.
Then test again by adding two pieces of spaghetti and see how much more load your bridge can take. Then add three pieces, four pieces... See how much more weight you can add each time before your bridge breaks!
2. Static Electricity
Have you ever felt your hair stand on end when you put on a jumper, or jumped on a trampoline, or rubbed a balloon in your hair? Have you ever felt a 'zap' when you've touched a car, or someone else? This is static electricity. Static electricity occurs when there is a build-up of electrons on something, giving it an electric charge. The electrons want to be in balance and when something else with less electrical charge touches them, they will transfer or jump across to the place with less charge, often giving you a zap or making your hair stand on end!
It is called 'static' electricity because the electrical charge is not moving or transferring from one place to another, it is static. It only moves when it comes into contact with something that has fewer electrons than it.
Today you are going to make some static electricity using a spoon, then use it to try and separate salt and pepper mixed together on a plate! The pepper is lighter than the salt so the static electricity will be able to attract it more easily and cause the pepper to stick to the spoon first.
3. Dancing raisins
In this experiment today we want to make raisins dance in carbonated (or bubbly) liquids - such as mineral or soda water, or even lemonade! Bette to use a clear liquid as you can see your raisins dance better!
Usually, raisins will sink when put into a liquid because they are denser, or have more mass, than the liquid. But when they are added to a liquid with carbon dioxide bubbles in it, they will begin to move around and dance!
I wonder if you can observe what happens and explain why the denser raisins are able to move around in the liquid? Then I challenge you to have a go at home and create your own dancing raisins! And if you don't have raisins, you can try adding sultanas or currants or even dried pasta into carbonated water and make them dance too! I wonder what will dance the best...
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