< >Show: 5 25
- the list
View as a
HypercoolingWhat You Need
A metal bucket
32 oz. of table salt
6 16oz bottled water
Two bags of crushed ice and Water
What You Do
Take three to six (sealed) plastic bottles of mineral water.
Place them in your bucket and pour in a bag of ice, add water so that the ice becomes slushy.
The lids of your water bottles should be sticking out the top of the ice/water mixture so you can handle them without freezing your fingers. Make sure they are evenly spaced in the bucket.
Pour in the salt, use 26 oz of salt if you only use three bottles and 32 oz for six bottles.
If you have a thermometer place it in the bucket.
Wait 35-545 minutes, but keep checking on the bottles, turn them gently to insure that they cool evenly.
When time is up you'll see a thin layer of ice on the outside of your metal bucket.
Take the bottle out and turn the bottle on its side. Swing it lightly back and then BANG it against a wall. Watch as the water slowly changes color and turns to ice.
Take a glass bowl and place a few ice cubes inside. Gently open the lid of your super cooled bottle of water. Slowly pour it onto the ice in the bowl. The liquid water should turn to ice as soon as it makes contact with ice cubes in the bowl. This means that you should be able to produce a tower of ice as you keep pouring.
When the bottles are super cooled they are just waiting around for something to trigger freezing. One theory is that the banging creates microscopic air bubbles near the surface in the bottles and these bubbles act as the impurity/nucleation site.
Pouring liquid water that lands as solid ice - this works because of the ice cubes already in the bowl. One of the best nucleation sites that you can use to form ice crystals, is other ice crystals
Fun With PhysicsWhat You Need
For Experiment 1:
Empty Jam Jar
Balloon or Comb
What You Do
Experiment 1: Sticky Rice: Get a clean jam jar. Fill to the top with rice. Hold the jar firmly with one hand, push a pencil right to the bottom. Pull the pencil up slowly but not all the way out. The push it back down again. If the rice level starts to drop, top up the rice. Eventually, the rice will compact around your pencil, and you will be able to lift the whole jar with the pencil. When this happens, the friction between the pencil and rice is so large that you cannot easily pull the pencil out!
Every time you plunge the pencil into the rice you are compressing the grains and making them pack more tightly together. The air gaps decrease in size and the rice grains rub against each other more. They can't move as freely, and start to arrange in a pattern that doesn't change. The rice you could previously pour like a liquid becomes solid.
With more grains of rice pressing on the pencil, and each one of those more tightly packed in, the friction between the knife and the rice increases.If the friction force between the rice and knife equals the combined weight force of the rice and container, then the balance of forces means the pencil is held in place. For the jar to lift as well, friction between its inside walls and the rice must also increase. That shows you the rice has moved and compacted even away from where you disturbed it with the pencil.
Experiment 2: Bend water with static electricity: Blow up a balloon or use a comb and rub it against your head to build up a static charge. Do this for several minutes to really get a decent charge. Then, turn a tap on: it should be on enough for a steady but slow stream of water to come out, not just drips. Bring the balloon close to the stream of water and observe what happens!
When two objects are rubbed against each other, some of the electrons from one object jump to the other. The object that gains electrons becomes more negatively charged; the one that loses electrons becomes more positively charged. The opposite charges attract each other in a way that you can actually see.
Experiment 3: Super bouncing: Do this outdoors with a lot of space. Grab a tennis ball. Drop it on the floor and see how high it bounces. Now grab a basket ball. Drop it on the floor and see how high it bounces. Now put the tennis ball on top of the basketball; support the basketball with one hand and the tennis ball with the other. Drop your two balls at exactly the same time.
When you drop the two balls together, they will separate just a little bit. The bottom one will hit the ground first, and will rebound. As it is on the way up, it hits the small ball, which is still on its way down. So you have a head-on collision, between balls of very different masses. When this happens, a lot of the energy of the big ball gets transferred to the small ball, so watch out as the small one will end up bouncing very high.
Rainbow GlassWhat You Need
Different coloured food colouring
Patience and a steady hand
What You Do
Line up the glasses and put 3 tablespoons of water into the first four glasses. Add one tablespoon of sugar to glass one, two to glass two, three to glass three, four to glass four. Stir thoroughly to dissolve the sugar. Now add a different colour foodcolouring to each glass. Pour 1/4 of glass four into glass five.
This gets a bit tricky and you'll need some practice, you must pour the next layer (glass three) so gently that it doesnt mix with the first layer. You can put a teaspoon just above the first layer and pour the mixture gently over the back of the spoon to minimise splash. The more slowly you do this, the better the results. When you have filled the glass to about the same width as the last layer, repeat with glass two, and then with glass one.
The different amounts of sugar in water create different densities of water. As you are layering them with the heaviest at the bottom, the different layers will 'sit' on top of each other. Eventually, due to particle dynamics, the layers will mix. The greater the difference in density, the longer the effect lasts. Unlike water and oil, however, once you mix the layers, they will not settle back.
Self Inflating BalloonWhat You Need
A used washed fizzy drinks bottle (lid not required)
Latex balloon (thinner the better)
What You Do
Place 2 teaspoons of yeast, 1 teaspoon of sugar and one cup of water into the bottle. Put the balloon over the top of the bottle and secure with the elastic band. Walk away...but keep a close watch on it.
Yeast is actually a micro-organism. The yeast is 'eating' the sugar and respiring. A product of respiration is Carbon Dioxide, which slowly fills up the balloon.
Make Your Own Lava LampWhat You Need
ransparent Jar with tight-fitting lid (jam jar or similar)
What You Do
Fill the jar to around the 3/4 mark with water. Then add food colouring of your choice (a drop at a time) until you have your desired colour. Add glitter (if you want). Fill your jar almost to the top with oil and leave for 15mins to settle. Then add teaspoons of salt - you will start to see a lava-lamp effect. Shine a flashlight through the jar and the effect is complete! When the salt dissolves, the oil will return to the surface. Add more salt to see the effect again.
il is less dense than water, and so rests on top. When you add salt, it sticks to the oil; because salt is more dense than water, it sinks - when enough salt attaches to a blob of oil, the whole blob sinks. When the salt dissolves in the water, the oil's low density causes it to rise up again.
items 1 - 5 of 13
start a list with results
close sorting window
use the search box to filter your list