Science at home! Fun homemade experiments for the little ones. We will learn about Density, Buoyancy, Mixtures and Emulsions !!

in steemiteducation •  7 years ago  (edited)

Hello friends of @steemiteducation, today I want to present a post that besides fun turns out to be educational for our children, those to whom we always want to desperatar their curiosity so that they are interested in something, well! Today we will perform two experiments that they will love, they will have fun and of course they will learn, they are very eye-catching experiments that will call your attention and yours too, I hope you like them and practice them with the little ones at home.

By making these experiments so simple the children will investigate and learn about Buoyancy, Density, Mixtures, Emulsions and they will also discover why they wash the detergent.

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But before starting with the fun it is always important to know the theoretical part so that we know what we are learning:

Buoyancy and Density:

The key to one substance floating or sinking in another is in a property of matter called density. The density of an object is defined as the relationship between its mass and its volume. If we have two balls of the same size (volume), one of wood and the other of steel, the densest will be the one with the highest mass, the steel. In summary, density is a measure of the mass that exists in a given space. Well, the less dense substances float in the densest.

Mixtures:

A mixture is the aggregation of several substances or bodies that do not chemically combine with each other. Each of the substances that make up a mixture is called a component, which, being together or separated, preserve their characteristic properties and intervene in varying proportions.

The emulsion:

An emulsion is the mixture of immiscible liquids. Daily examples of emulsions are milk and mayonnaise. For the emulsion to occur, the presence of an emulsifier or emulsifier is necessary.

Now if the fun begins!

Flotability and density experiment with ice, water and oil

We already know that water and oil do not mix, but separate in layers. The water is located in the bottom layer and the oil above, floating in the water. Great, but what if instead of liquid water we had ice? Would it also sink into the oil or would it float?

Children can answer this question by doing a simple experiment that apart from knowing more about buoyancy, density and mixtures, they will have the opportunity to know some properties of the most important substance for life: water.

Materials:

  • Some ice cubes. We use colored ice coloring the water with food coloring. It is not absolutely necessary but in this way the experiment is very showy.

  • A glass with oil. It will be more striking the higher the glass.

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Process:

  • Put an ice cube in the glass with oil.
  • Watch and wait for the ice to melt.
  • Keep watching and adding ice. - If the ice cubes are colored, the show is impressive.

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What happen?

What happens is that the water sinks in the oil because it is more dense than the oil and, nevertheless, the ice floats in the oil because it is less dense than the oil. With the experiment we have verified that the ice floats in oil but as soon as it begins to melt, the drops of liquid water have a higher density and fall to the bottom. What is the reason for this change in density?

Molecules in solids and liquids :

In a liquid the molecules are in constant motion vibrating and moving freely. In a solid, on the contrary, the molecules can not move, they are only allowed to vibrate around a fixed position. If a liquid freezes, its molecules stop moving. In this situation, it would be logical to think that they would stay closer to each other occupying less space, which would result in an increase in density. Most substances behave "logically", that is, they are denser in the solid state than in the liquid state. However, in the case of water, the opposite happens: ice is less dense than liquid water. Why does water behave like this?

Structure of the water molecule:

The water molecule consists of two hydrogen atoms linked by covalent bonds (sharing electrons) to an oxygen atom. The atoms are not placed in a linear fashion, but the bonds form an angle of approximately 104.5 °. It is thanks to this angle and that oxygen is more electronegative than hydrogen (the shared electrons are located closer to oxygen than to hydrogen) that the water molecule is polar. Being polar means that on the one hand it has a negative charge (oxygen side because it has the electrons closer) and another positive charge (hydrogen side). As the charges of different sign are attracted, the water molecules attract each other. Due to their attraction, they are formed between what are called hydrogen bridges, which are junctions between the oxygen of one molecule and the hydrogen of another.

The joints by hydrogen bridge are very strong overall but not so much individually. When the water is in liquid state, for example at 30 ° C, its molecules move rapidly in all directions. Due to the movement, the hydrogen bridges are breaking and forming constantly. If the water cools, its molecules lose energy and its movement is reduced. As a result, hydrogen bridges are gaining ground. So much so, that below 4 ° C more hydrogen bridges are formed than those that break. The result is the formation of a hexagonal crystal structure with many free holes: ice. With so many gaps it is not strange that the density of ice is less than that of liquid water.

Let's continue with the fun !! Let's go with the other experiment:

Experiment with water, oil and detergent: emulsion

Oil and water do not mix, do they? With the help of detergent it is possible to mix them and create an emulsion. By making this experiment so simple, children will learn about buoyancy, density, mixtures, emulsions and also discover why they wash the detergent.

Materials:

  • Water.
  • Cooking oil
  • Detergent for the dishes.
  • Coloring (optional)
  • Jar with lid.

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Process:

  • Put water, oil and coloring in the jar in the order you want. Do not fill it completely, then we will add detergent.
  • Shake the mixture and let it sit. After a while you will notice that two layers have formed. Down will be the water with the dye and the oil will be floating above.
  • Take a good stream of detergent for the dishes, put the lid on the jar and stir. You will have managed to mix two immiscible substances in an emulsion.

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What has happened?

Oil and water are immiscible. The water molecule is polar, on the one hand it has a negative charge (where the oxygen is) and on the other it has a positive charge (where the hydrogens are). As the charges of different sign are attracted, the water molecules feel a strong attraction between them, they present a great cohesion. However, the oil molecule is not polar. Their charges are distributed throughout the molecule more uniformly, not only at the ends, as in the case of water. The oil molecules also feel a great attraction between them. If the water prefers to be with water and the oil prefers the oil, there will be no way of mixing them in a homogeneous mixture.

The oil floats in the water. Water is always below the oil and the key is that the density of the water is greater than that of the oil. The less dense liquids float in the denser ones.

The detergent. Its molecules consist of a hydrophilic end that dissolves in water and a hydrophobic zone that repels water but dissolves into non-polar substances. The hydrophilic end joins the water and the hydrophobic end to the oil creating a bond between the two. This is one of the reasons why the detergent removes dirt, joins the grease and water at the same time.

The emulsion. By adding the detergent and stirring, small balls of oil are formed. The spheres do not unite with each other, but they remain separated thanks to the emulsifier that surrounds them, being distributed in the water in a practically homogeneous way. The spherical shape is due to the fact that the hydrophilic end of the detergent molecule is negatively charged. Charges of the same sign are repelled and to be as far as possible from each other are placed giving rise to a sphere.

Children love to do experiments. With them, while having fun, they learn and ask questions about the world around them. Among its many benefits, scientific exploration feeds the child's natural curiosity, fosters his interest in science, stimulates reasoning and logic, improves his ability to solve problems, increases his self-esteem and prepares them to understand more complicated scientific concepts in the future.

To enjoy science is not necessary to have a laboratory, you will be surprised at the amount of experiments that can be done with a few homemade materials. So do not wait any longer, get down to work and have fun with your children or students.

I hope that this article has been of your interest and help and I hope you in my next post.

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this is an interesting way of bringing chemistry home. it relates the chemical principle aand processes to everyday life and experiences.

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