Dancing Popcorn
Materials:
- Water
- Plastic cup, bottle or jar
- Unpopped popcorn
- 1 teaspoon
- 1 tablespoon
- Sodium Bicarbonate
- Vinegar
What to do:
1. Fill the plastic cup with water until it is ¾ full
2. Measure half a teaspoon of sodium bicarbonate.
3. Add the sodium bicarbonate to the water and stir until it has dissolved.
4. Add 4 kernels of popcorn to the cup.
5. Add 1 tablespoon of vinegar to the cup.
6. Watch closely.
Why is this happening?
The kernels of popcorn sink to the bottom at first, but bubbles are created because of the vinegar and sodium bicarbonate, so the kernels move up and down with the bubbles.
Magic Milk
Materials:
- Whole milk
- Food colouring
- Bowl
- Toothpick
- Dishwashing liquid
What to do:
1. Pour ½ cup of milk into a bowl.
2. Add 2 drops of food colouring in different areas of the bowl. You can use up to 4 different colours.
3. Dip the toothpick into dishwashing liquid.
4. Stick the toothpick with the dishwashing liquid on the end into the centre of the bowl of milk.
5. Watch what happens.
Why is this happening?
Milk is mostly a mixture of fat and water. The food colouring mixes easily in the water but not in the fat. So, the more fat in the milk the least mixing occurs. The detergent causes the colours to move because of the way the detergent acts with the fat and the water.
You could try the experiment with other kinds of milk (powered, skim, low fat, soy) and see if you get different results.
Lava Lamp
Materials:
- Clear plastic water bottle or jar
- Water
- Food colouring
- Cooking oil
- Salt
What to do:
1. Fill the water bottle up till it is two thirds full.
2. Add 2-3 drops of food colouring to the water.
3. Pour in a small quantity of oil, just enough to form about a 2cm layer on top of the water.
4. Sprinkle a few pinches of salt onto the oil and watch what happens.
5. Keep adding salt to make your experiment last longer.
Why is this happening?
Have you heard the saying -- "oil and water don't mix"?
A teaspoon of water is much denser than a teaspoon of oil -- in other words, it's heavier. Density is a measurement that can be used to explain why things sink or float.
Oil makes a layer on the surface of the water because it is less dense, or lighter, than the water. When the salt is sprinkled into the bottle, it sinks to the bottom taking a glob of oil with it. The salt then dissolves in the water leaving the oil to float back up to the surface.
(Source: http://www.abc.net.au/spark/experiments/s1158082.htm)
Black Magic:
Materials:
- Scissors
- White or brown coffee filters
- Black marker (not permanent)
- Water
- Plastic Cup
What to do:
1. Fill the plastic cup with water so that it is ½ full.
2. Use the scissors to cut a long strip off the coffee filter
3. Use the black marker and colour in a small section in the middle of the coffee filter strip.
4. Dip the coffee filter strip into the water- make sure that the water just touches the part you have coloured in.
5. Rest the coffee filter strip in the water, leaving the water touching the black mark.
6. Watch closely what happens. It can take 5 minutes or more before all the different colours will begin to show. How many colours can you see?
Why is this happening?
Most non-permanent markers use inks that are made of coloured pigments and water. On a coffee filter, the water in the ink carries the pigment onto the paper. When the ink dries, the pigment remains on the paper.
When you dip the paper in water, the dried pigments dissolve. As the water travels up the paper, it carries the pigments along with it. Different-coloured pigments are carried along at different rates; some travel farther and faster than others. How fast each pigment travels depends on the size of the pigment molecule and on how strongly the pigment is attracted to the paper. Since the water carries the different pigments at different rates, the black ink separates to reveal the colours that were mixed to make it.
(Source: http://www.exploratorium.edu/science_explorer/black_magic.html)
Balloon Blow-Up
Materials:
- Clear plastic bottle
- 1 balloon
- Baking soda
- Vinegar
- 2 spoons
What to do:
1. Pour a layer of vinegar, about 4-5cm thick, into the plastic bottle.
2. Open up the mouth of the balloon. Have a friend put 1 teaspoon of baking soda into the balloon with a spoon.
3. Without spilling any of the baking soda, stretch the mouth of the balloon over the mouth of the bottle.
4. Turn the balloon completely upright so that the baking soda inside the balloon pours into the bottle with the vinegar.
5. Watch what happens!
Why is this happening?
Baking soda is a chemical called sodium bicarbonate and it reacts with vinegar. Vinegar is called acetic acid. These two chemicals react and form something new. You can see that a reaction is happening.
What things happened? The baking soda and vinegar fizzed and you may have seen some bubbles. The bottle probably feels cool around the mixture. The balloon blew up. All of these observations tell us that a reaction occurred.
(Source: http://www.science-house.org/CO2/activities/co2/balloon.html)
Ooze
Materials:
- Bowl
- Cornflour
- Water
- Large spoon (or you can use your hands!)
- Food colouring
What to do:
1. Place the cornflour in the bowl.
2. Add 3 drops of food colouring to the mixture.
3. Use the large spoon to stir the cornflour while adding the water a little at a time. Keep stirring and adding small amounts of water until all the cornflour is wet.
4. Keep adding small amounts of water and stirring until a thick slime forms.
5. Notice that the slime is thick when you are stirring, but becomes runny when you stop?
Why is this happening?
Cornflour slime is a stir-thickening fluid which means that its runniness changes depending on whether or not the fluid is being stirred. By stirring the cornflour slime, you are applying a force. It is this ‘shear force’ which causes the slime to become thicker. As soon as the shear force is removed, the slime becomes runny again.
(Source: http://sciencesquad.questacon.edu.au/activities/cornflour_slime.html)
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