Physics begins with questions - “what will happen if...?” And the questions are based on observations.
- How to arouse an interest in observations in a grandson?
- Without much effort, if you ask yourself questions, get carried away and are surprised)
A week has passed, the second has begun, the riddle from the previous issue remains unsolved:
- what's wrong with liquids?
In one comment they noticed that there was oil sitting at the bottom, what kind of chemistry is that?
But it's not a matter of chemistry - it's pure physics.
Ordinary vegetable oil and water are like water.
Oil stain under normal conditions
It floats where it's supposed to - on the surface.
But, doing an experiment with a leaf and atmospheric pressure, the glass was covered with paper -
the oil stuck to it,
Like a drop of water - only upside down: it should float up,
but it hesitated and stuck to the paper surface.
- What will happen to the water droplets in the oil?
- They will fall to the bottom, the water is heavier...
Pour a layer of oil on top of the water (so as not to waste too much) -
Let's release a few drops of water from the tube -
It would behoove her to drown in oil, but the drops hang like rain under the eaves.
If you add a little water to each on top - they swell, stretch and come off -
exactly like the classic drops.
Gradually, one after another, the water balls separate from the surface and descend, but instead of
in order to dive into their native aquatic environment - they settle on the border of oil and water like funny cakes)
(pink ones - slightly tinted to distinguish them from random air bubbles in the photo)
The paint dissipates, the balls become discolored, but they still live long enough to leisurely examine their transformation.
If you're lucky with the size, you can observe an interesting phenomenon:
the thickest drop “flows” through the boundary of the layers,
a noticeable bump forms under it,
It swells... and if you knock on the glass from below -
the drop comes off and floats up again!
- But it’s all water, how does it hold on?
such “buns” without merging with the general body of water?
It is difficult to catch the focus inside the water-oil environment.
If you repeat the experiment live and look closely, it is noticeable even to the eye that the drops
not just like that, but in a thin oil shell. And they don’t stick to each other.
Real water anti-bubbles!
Question for grandson:
-What is thicker, water or oil? What's heavier?
A stick of butter floats perfectly even right in the pack,
Decorative candle drifts without a stand,
liquid fat invariably collects on the surface of the soup.
Those. what is thicker ("according to science" - has high viscosity) it may be easier.
Oily or paraffin molecules, complex and branchy -
Because of this, layers of viscous liquids do not move as readily when pouring or stirring with a spoon,
like layers of water populated by small, nimble molecules; fat or melted paraffin
splash sluggishly, flow slowly - and seem viscous: we consider them more “thick”,
but water molecules sit more tightly - a glass of water is heavier than a glass of oil: water has more density.
Nail polish may seem thick and viscous - but it’s also lighter than water!
- floats on water like an oil film
And just like oil, it can be collected on paper - an almost clean water surface remains -
And if you cover it with transparent plastic, the varnish patterns will be copied onto it.
Detergent is heavier than water
soapy liquid snakes slowly settling, like paste from a tube
The bar of soap also sinks. Soap floats only in the form of foam.
So that the youngest viewers don’t get bored, let’s blow into the tube:
there was a solution on the bottom - it was blown away!
It blew my mind :)
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Let there be an oil stain,
let's drop water into it (tinted, for greater effect, so that it is better visible)
Floats.
- There were no special conditions in the glass, the effect is consistently manifested
regardless of the amount of liquid.
Now let's try adding a drop of detergent.
At first, it forms a bulge, just like water, floating on the surface of the spot.
But soon it begins to sink to the bottom, pushing the oil medium
Just like when washing - the soap is matched to the greasy stain.
And he gets carried away by the water!
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Fun for beginner physicists: let's color the water!
Will it be possible to paint the foam?
Children as young as two years old invariably like it -
The water was clear, but it turned yellow. Added blue - it became green!
It was at the bottom of the bottle, they dropped some soap, shook it - foam to the top.
Magic, no less)
When exposed to light, the foam is colored. If you look closely: where there are air bubbles, it is white,
and where the particles of water rose with the foam, the paint showed through.
It is noticeable how the water gradually drains, the foam brightens until it turns white everywhere.
You can shake the water without soap; it bubbles but settles quickly.
- Is it possible to foam the butter like this?
If you shake the bottle very, very, very hard?
A few small, tiny bubbles form, it doesn’t look like foam at all..
- What if you add oil to the water instead of soap?
More like cream or mayonnaise! =)
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Beginner Pollack's Studio:
Drip and make patterns
White gaps inside the colored ones and swirling mustaches are obtained if you touch
colorful stains with a toothpick, after dipping it in liquid soap -
Workshop for a young experimenter:
A tube instead of a pipette!
Place in water. Naturally, the tube will fill level with the liquid level.
Pinch the top hole with your finger and you can lift it - the water won’t go anywhere!
(Oil can be picked up just fine in the same way, just about anything - alcohol, vinegar)
As soon as you let go of your finger, it immediately pours out.
Mystery?
No, it's not a mystery yet
The riddle of this issue: “Is it easier to wipe off with a napkin or rinse with water?”
Do you remember where this comes from and what it's about? And who is really right?
It turns out you can walk on water! In Turkey there is a salt lake that people walk along in the summer. Salt covers its surface like a crust of ice.
Swimming beetles can also run on water. But that's a completely different story...
Let's return to salt. You can make a small salt lake at home.
Let's conduct an experiment. For this we need 3 liter jars, 3 raw eggs and of course salt. Learned? It seems like everyone made eggs float in water when they were kids.
Pour plain water into jars. Add 2 tablespoons of salt to one of them, 5 tablespoons of salt to the other. Mix everything well and lower the eggs into the water.
- An egg will sink in a jar of fresh water.
- In a jar with a little salt, the egg will float in the middle of the jar.
- And in a cool salt solution, the egg will float to the surface.
Why is this happening?
Salt water is denser and heavier than ordinary fresh water. So she holds the egg on the surface. That’s how in a salt lake you can lie on the waves, like on a sofa, and read a book. It’s all about the density of the water.
Pour some water into a glass. Then they lowered a cork and a piece of paraffin candle into the water. They, like boats, floated on the surface of the water. Add oil to the glass. It turned out that the plug continued to float on the surface, but now there was oil, and the paraffin sank lower into the oil layer.
Why did it happen?
Oil is lighter than water, so it is located above the water. Cork is lighter than oil, and paraffin is lighter than water, but heavier than oil. This is such a light-heavy story :)
Knowing the density of some substances, come up with your own multilayer liquids. Density is given in g/cm 3
- Honey 1.35
- Glycerin 1.30
- Whole milk 1.03
- Clean water 1.00
- Sunflower oil 0.93
- Ice 0.90
- Alcohol 0.80
- Gasoline 0.71
- Cork 0.24
Check out our experience on the density of substances :)
Experiments are different and not only with liquids. And we have already conducted experiments with densities today. That's why I want to GIVE you a collection of experiments with sound. Add volume, zing, and some controlled noise to your life. Believe me, it's very interesting.
Happy experimenting! Science is fun!
You will need
- - freezer,
- - several containers,
- - household water filter,
- - Activated carbon,
- - rubber tube.
Instructions
The simplest and most accessible method in everyday life is freezing. This method was used even in deep water. It consists of the following: the container is cooled to sub-zero temperatures until the water freezes. The easiest way to do this in modern conditions is to place it in the freezer. The oil temperature is usually much lower than the freezing point of water. After some time, the water will turn into ice, but the oil will remain liquid. It can be easily poured into a separate bowl, and the surface of the ice can be carefully wiped with a dry cloth to remove any remaining oil.
Another simple method is filtering. Any household filter is suitable for this. True, first you will need to drain most of the oil so as not to subject the filter mixture to too much stress. After the oil has been drained, run the water through the filter. It will come out without an oil film.
A more complex method is absorption. It consists of placing a special substance (the so-called absorbent agent) in a container with oil, which absorbs foreign impurities, leaving only water. The most accessible of these substances is the usual activated one. True, you will need quite a lot of it: take from three to one relative to the available volume of oil. Place all this in an airtight container and shake vigorously for a long time. You can visually evaluate the end of the process. If necessary, change the dishes several times, as some of the oil will inevitably remain on the walls. It may take several agent boot cycles. But at the end you will get clean water without any impurities.
And finally, you can do it quite simply. Take a long rubber tube. One end of it needs to be lowered into a container with water and oil (for convenience, it can be secured with tape), the other - into a bowl located half a meter below this container. Attention: the upper end of the tube must be at the very bottom of the filled container. Prepare two more containers in advance: for oil and for intermediate substance. Then everything happens in much the same way as in the process of draining fuel from a gas tank. Suck air from the lower end of the tube and lower it into a previously prepared container. The water will immediately begin to drain. The process must be carefully controlled, and when almost all the water has flowed out of the upper container, quickly transfer the tube to a container for the intermediate substance. After waiting for the oil to pour out of the tube, place the container intended for oil. If everything is done quickly and correctly, the volume of the intermediate substance will be very small, and water and oil, as required, will be poured into two different containers.
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