36 more hours of material to end the season! Grandma is trying all she can. She seems to have family that do not seem to respect her or her home. Grandpa and I got it cleaned and I keep trying to push. Grandma figures 6-10 hours today, 6-10 hours tomorrow, 12 on Thursday, and 6 left on Friday, and we will have done it. Please bare with me. Grandma has some more experiments from Book (12) for you on this day: 14 on Liquids(which I may have already given you but we will repeat them) and 9 on Buoyancy. Grandma has only till 9 before she must go to the doctors appointment, bare with.
The first experiment is called String of pearls. Let a fine jet of water pour on a finger held about two inches under the tap. If you look carefully, you will see a strange wave-like pattern in the water.
If you bring your finger closer to the tap, the waves become continuously more ball-shaped, until the water jet resembles a string of pearls. It is so strongly obstructed by the finger that because of its surface tension--the force which holds the water particles together--it separates into round droplets. If you take your finger further away from the tap, the falling speed of the water becomes greater, and the drop formation is less clear.
The next experiment is called Water knots. An empty two-lb. can is pierced five times just above the lower edge with a thin nail. The first hole should be just over an inch from the fifth. Place the tin under a running tap, and a jet will flow from each hole. If you move your finger over the holes, the jets will join together.
The water particles are attracted to one another and produce a force acting into the interior of the liquid, the surface tension. It is also this force which holds a water droplet together. In our experiment the force is particularly clear, and it diverts the jets into a sideways arc and knots them.
The third experiment is called Mountain of water. Fill a dry glass just full with tap water, without any overflowing. Slide coins carefully into the glass, one after the other, and notice how the water curves above the glass.
It is surprising how many coins you can put in without the water spilling over. The water mountain is supported by surface tension, as though it is covered by a fine skin. Finally, you can even shake the contents of a salt cellar slowly into the glass. The salt dissolves without the water pouring out.
The fourth experiment is called Ship on a High Sea. Place a half dollar or 10 new pence on the table, and on one side of the coin a small cork disk. How can you move the cork to the exact center of the coin without touching it?
Pour water on to the coin-drop wise, so that it does not spill over-to form a water mountain over the surface. At first the force of gravity holds the cork on the edge of the slightly curved water surface. If you now pour on more water, the pressure of the water on the edge increases, while it remains constant on the top. So the cork moves up the hill to the middle, which is the region of lowest pressure.
The fifth experiment is called Floating metal. Fill a bowl with tap water. Place small metal objects on blotting paper and carry it carefully into the dish with a fork. After a time the saturated blotting paper sinks, but the small objects remain floating.
Since metal is heavier than water, it should really fall to the bottom. The liquid particles are held together so strongly by a mysterious force, the surface tension, that they prevent the objects sinking. Surface tension is destroyed by soap.(maybe add some soap and see what happens)
The sixth experiment is called Watertight sieve. Fill a milk bottle with water (or try a jar) and fasten a piece of wire gauze about two inches square over its mouth with a rubber band(attach that with a wire across the square or the sides bent down for the rubber band to catch). Place your hand over the top and turn the bottle upside down. If you take your hand away quickly, no water comes out. Where water comes into contact with air, it surrounds itself as though with a skin, because of its surface tension. Each opening in the wire gauze is so well sealed, that air can neither flow in nor water flow out. This also occurs with the fine holes of tenting material, which is made water-repellent by impregnation, and rain drops cannot get through because of their surface tension.
The seventh experiment is called Rope trick. Knot a piece of string into a loop and allow it to float in a bowl of water. If you dip a match into the middle of the irregularly shaped loop, it immediately becomes circular.
The match has this magic power because it was previously dabbed with a little washing-up liquid. This spreads in all directions when the match is dipped into the water and penetrates between the water particles, which were held together like a skin by surface tension. This 'water skin' breaks in a flash from the place where the match is dipped in outwards. The liquid particles which are made to move push against the loop and make it rigid.
The eighth experiment is called Speedboat. Split a match slightly at its lower end and smear some soft soap into the slit. If you place the match in a dish of tap water, it moves forwards quickly for quite a time. Several matches could have a race in a bath tub.
The soap destroys the surface tension of the water by degrees as it gradually dissolves. This causes a backward movement of the water particles, which produces as a reaction a forward movement of the match. With a drop of detergent instead of the soap the movement would be like a rocket.
The ninth experiment is called Little railway. Make a rectangular frame about 1 x 3 inches out of thin wire. Place a straight piece of wire loosely over the center. Dip the whole thing into washing-up liquid, so that a fine film stretches over it. If you pierce through one side, the piece of wire rolls backwards to the other end of the frame. The liquid particles attract one another so strongly that the soap film is almost as elastic as a blown-up balloon. If you break the cohesion of the particles on one side, the force of attraction on the other side predominates, the remaining liquid is drawn over and the wire rolls with it.
The tenth experiment is called Soap bubbles. In each plastic detergent bottle that is thrown away there are still a thousand soap bubbles! Cut off the lower third of an empty detergent bottle and mix 10 teaspoonfuls of water with the detergent remaining in it. Bore a hole in the cap, push a straw through it, and a match into the nozzle. Put some of the liquid into the pipe and blow!
The liquid particles in the soap bubbles are compressed from outside and inside by surface tension. They hold together so strongly that they enclose the air flowing from the pipe and so take on the shape of the smallest surface, which is a sphere.
The eleventh experiment is called Bag of wind. Prevent a large soap bubble sitting on the pipe from flying off by closing the end of the straw with your finger. Hod it near a candle flame and then take your finger away. The flame leans to the side, while the soap bubble becomes smaller and vanishes.
Although a soap bubble film is generally less than one-thirty-thousandth of a inch thick, it is so strong that the air inside is compressed. When the end of the straw is released, the liquid particles contract to form drops again because of the surface tension, and thus push the air out.
The twelve experiment is called Water rose. Cut out a flower shape from smooth writing paper, colour it with crayons and fold the petals firmly inwards. If you place the rose on water you will see the flower petals open in slow motion. (The flower is like a drawn sun with a spiral in the middle like a circle only many sides and points from each side--looks like the sun.)
Paper consists mainly of plant fibers, which are composed of extremely fine tubes. The water rises in these so-called capillary tubes. The paper swells, and the petals of the synthetic rose rise up, like the leaves of a wilting plant when it is placed in water.
The thirteenth experiment is called Game of chance. Fill a preserving jar, as tall as you can find, with water, stand a brandy class in it and try to drop coins into the glass.(the glass is shaped low and wide) It is very surprising that however carefully you aim, the coin nearly always slips away to the side.
It is very seldom possible to get the coin straight into the water. The very smallest slope is enough to cause a greater resistance of the water on the slanting under side of the coin. Because its center of gravity lies exactly in the middle, it turns easily and drifts to the side.
The last and fourteenth experiment is called Sloping path. If you cool a boiled egg in the usual way under the water tap, you can make a surprising discovery. Hold the saucepan so that the water runs between the egg and the rim. If you now lean the saucepan to the other side the does not, as you would expect, roll down the bottom of the saucepan, but stays in the stream of water.
By Bernouilli's Law the pressure of a liquid or a gas becomes lower with increasing speed (going back to the experiments on air in which they blow things forward or into a can and then sucking them to them as the last experiment sucking air inward through a funnel instead of downward flow from the funnel). In the stream of water between the rim of the pan and the egg there is reduced pressure, and the egg is pressed by the surrounding water, which is at normal pressure, against the pan.
Grandma will have to finish the experiments later today. Take care.