Thames & Kosmos Ooze Labs: Chemistry Station handleiding

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Handleiding

Chemical foaming

YOU WILL NEED

2 test tubes, chemistry station, baking soda,

household vinegar, dish detergent, water

HERE’S HOW

1. Fill both test

tubes with water

to a height of one

centimeter in the

tube. Then add a

half centimeter of

vinegar to each

tube. Finally drip

five drops of dish

detergent into one of the two tubes.

2. Add one scoop of baking soda to each test

tube and compare how the foam behaves.

Mooooving colors

YOU WILL NEED

Small test tubes with lids, dye tablets broken

into eighths, chemistry station, large

measuring cup, petri dish, pipette, milk, cotton

swab, liquid dish detergent

HERE’S HOW

1. Fill the small test tubes with 4 ml of water

and add about an eighth of the red dye

tablet. Screw the lid on the test tube. Shake it

to mix the water and dye tablet. Repeat this

step using the yellow and blue dye tablets in

the two other test tubes.

2. Place the bottom of the petri dish in the

base of the chemistry station. Use the large

measuring cup to measure out 25 ml of milk.

Pour it into the base of the petri dish.

3. Use the pipette to add a few drops of the red,

blue, and yellow dye solutions in the center

of petri dish.

4. Place the cotton swab in the liquid dish soap.

Then dip the cotton swab into the center of

the petri dish. What do you observe happens

to the dye solutions when the cotton swab

touches the milk?

WHAT’S HAPPENING

Like the detergent mixture in Experiment 10, milk is an emulsion containing water, fat

molecules, and proteins. Different parts of the detergent molecules are attracted to the

different molecules that are in milk, so the detergent is able to move quickly through the milk.

As they move, the detergent molecules pull the dye colored solutions through the milk.

WHAT’S HAPPENING

In both test tubes the solution foams up

vigorously because the vinegar is an acid

and the baking soda is a base. The foam

quickly falls back down again in the tube

without the detergent, but the foam

remains stable for a longer period of

time in the tube with the detergent. This

stability is caused by the detergent,

which surrounds the bubbles with a

protective layer. The bubbles that

resulted from the reaction don’t contain

normal air, but rather carbon dioxide

formed from the reaction.

› › › EXPERIMENT 12› › › EXPERIMENT 11

Ooze Labs Chemistry Station

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