GCSE PHYSICS - What is an Insecticide? - How can an Electrostatic Charge help Crop Spraying?

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Using an Electrostatic Charge with an Insecticide Spray.

What is an Insecticide?

An insecticide is a chemical that kills insects.

Why are Crops Sprayed with an Insecticide?

Crops (plants grown for food) are sometimes sprayed
from an aircraft with an insecticide to reduce
the amount of the crop which gets eaten by insects.

The advantage of spraying crops from an aircraft
is that large areas can be sprayed very quickly.

The disadvantage is that it is difficult to control where
the spray will fall on the fields. Some parts of the field will
receive more insecticide than others. Some insecticide is
blown away on the wind and does not fall on the crop at all.

How can an Electrostatic Charge help Crop Spraying?

If the insecticide is given a electrostatic charge as it leaves
the aircraft then much more of the spray reaches
its target and the spray droplets are spread out more evenly.

This happens because the droplets with an electrostatic
charge are attracted to the crop even though the crop is
neutral. See the page for neutral objects to explain this.

The insecticide droplets spread out more evenly
because they all have the same charge and repel each other.

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