The kitchen is like a chemistry laboratory. The ingredients in the cupboard are chemical crystals. As you already know, custard contains starch, which makes it thick and semi-solid. Vinegar and lemon juice are acidic, while sodium bicarbonate is alkaline. Refrigerators, cookers and food processors are like scientific instruments for cooling, heating or cutting and mixing various ingredients. Here are some experiments that can help you understand more chemicals in the cupboard.

Think about it.

Make custard.

point out

Don't use instant egg batter, it contains sugar and condensed milk.

Materials or appliances

Egg batter or corn flour?

platform scale/balance

bowl

measuring glass

water

spoon

1. Measure175g of batter. Pour it into the bowl.

2. Measure125ml of water with a cup.

3. Add water slowly. Stir into a yellow dough.

4. Add water or batter to make it moderately sticky.

5. Gently touch the batter and feel it can flow like a liquid (Figure 3).

6. Knead this "restless" egg paste into a ball. Release one hand and the dough will collapse and turn into pancakes. Next, the dough can't be stretched and is easily broken (Figure 4).

Uncover the secret of the experiment

The batter is solid and the water is liquid. When you mix the two together, you become a suspension. The batter particles are suspended in water and evenly dispersed. When you slowly stir this mixture, the particles in it will still be evenly distributed.

Shake the custard, it's like a liquid. When you rub it quickly, the particles will collide with each other, and then it will have the characteristics of a solid.

Making colloidal "earthworm"

Pour a small bag of gelatin into the plate. Find an adult to help you pour 150 ml of hot juice. Stir until gelatin is completely dissolved. Then let it cool. Immerse several thick straws and fill the test tube with mixed liquid (Figure 1). Put the plate in the refrigerator and let the straw solidify. Finally, roll the straw into a curved fruity "earthworm" with a rolling pin (Figure 2).

Earthworms can bend because they are made of a colloid called gel. Molecular model of gelatin decomposition by hot fruit juice. When the mixed liquid cools, it combines into a new model-it mixes with the liquid to form a gel.

Shenqi baking powder

In a bottle, mix two spoonfuls of baking powder, one spoon of sugar and two spoonfuls of warm water. Put a balloon in the bottle mouth. Put the bottle in warm water. The balloon will magically expand!

I see

Heat and water activate microorganisms in baking powder. When microorganisms eat enough sugar, they will spit out carbon dioxide and blow up big balloons.

Hard starch

Starch can be used to size clothes. Make a mixture of corn flour, water and food coloring, and soak several ropes in the mixture (Figure 1). Stir the rope, then roll it into an interesting shape and put it on a plate. Put the plate in a hot place, and starch will be left after the water evaporates. Starch hardens ropes, so they can keep their shape (Figures 2 and 3).

You can try to stick these rope patterns on colored paper as decoration.

margarine

The original margarine formula was: "Mix hot beef fat, pig's gastric juice, milk and water." However, nowadays margarine is mainly made of vegetable fat, so people think that eating margarine is more beneficial to health than butter.

Colloids are produced when particles of one substance are suspended on another. Water droplets float in the air and become fog; The gas floats on the cream and becomes whipped cream; Water droplets float on chewing gum and become jelly.

I see

Mixing some materials in the kitchen can make glue that is both solid and liquid. It can also be made into gel, and carbon dioxide gas can be generated by activating microorganisms.