Safety first 4: Only use syringes from a pharmacy!
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4a. Acquaint yourself with a syringe: From millilitre to microlitre
Chemistry investigates substances like water, air, soil, food, fuels.
This needs measurements: you will start by measuring how much space a water drop needs.
Each measurement consists of a number, a unit (litre), sometimes a prefix (milli-, micro-):
Your syringe has space for 1 millilitre [mL] ( = "100 units") = 1000 microlitre [µL].
The space a substance takes is called its volume.
What you need
Insulin syringe 1 mL, sticky tape, infusion bottle 50 mL, injection bottle 5 mL, tray with some water.

Experiment 1    Prepare a syringe. Take exactly 1 mL of air with it (photo 1): Measure the volume of one air bubble.
1. Unpack a sterile syringe.  2.  Cover  the inscription by a piece of sticky tape.
3. Fill it with exactly 1,0 mL (= 100 "units" = 1000 Mikroliter) of  air like shown in photo 2.
4. Dip the mouth of the syringe into the water of the tray.
5. Count how many air bubbles you can press from the syringe with  1 mL (1000 Mikroliter [µl] ) :
Result 1:  1 mL (1000 µL) gives ..... big air bubbles. [The volume of  1 air bubble is 1000:... = ... microlitre (µl).]

Experiment 2     Fill the syringe with exactly 1 mL of  water: Measure how much water a Liquemin bottle takes (photo 4)
Photo 1: 1. Have exactly 1 mL of water free of air bubbles in your syringeRemove allntferne alle Luft-Blasen durch Pumpen und Klopfen.
Photo 2:  2. Transfer the water to the bottle in big drops. Count the drops per syringe. Write down. Observe the drop as lense.
Photo 3: 3. Repeat transfering 1-mL samples until the water in the bottle forms a curve on the surface.
Result  2a: 1 mL (1000 µL) of water gave .../ .../ .../ .../ .../ .../ big drops. average: ... big drops per mL.    [The volume of 1 water drop is 1000:... = ... microlitre (µl).]

Result  2b: The Liquemin bottle took ...,.. mL of water. ( = ... mL + ...... drops)                                          [The volume of the Liquemin bottle + curve is  ....,.. ml Wasser.]
Experiment 3     Carefully turn the bottle full of water upwards down above the tray

Home experiment   Right photo: Repeat Experiment 2 and 3 with water treated with some drops of washing-up liquid

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