[Sci9] HUMAN BODY ELECTRICITY

HUMAN BODY ELECTRICITY

by JHS Brighton

​How does the body make electricity?

​Everything we do is controlled and enabled by electrical signals running through our bodies. As we learned in intro physics, everything is made up of atoms, and atoms are made up of protons, neutrons and electrons. Protons have a positive charge, neutrons have a neutral charge, and electrons have a negative charge. When these charges are out of balance, an atom becomes either positively or negatively charged. The switch between one type of charge and the other allows electrons to flow from one atom to another. This flow of electrons, or a negative charge, is what we call electricity. Since our bodies are huge masses of atoms, we can generate electricity

​The Signals

When we talk about "signals", it is like the conjunctions to the brain, or synapses "fire works" between our nerve cells telling our hands to contract around a door handle. Shortly, electricity is carrying messages between point A and point B.

In our bodies, electrons aren't flowing along a wire; instead, an electrical charge is jumping from one nerve cell to the next until it reaches its destination to send or receive "response".

​Human Body as a Portable Power Source

​Humans generate heat as a side effect of metabolism, and to maintain core body temperature at approximately 37°C.

On average, around 58.2 W/m² of heat generated, though not all of it exits through the skin, as some is lost through exhalation and perspiration.

Heat from the skin is transferred to the lower temperature surroundings by convection and radiative transfer throughout the body. The rate depends on the part of the body, with muscle acting as an insulator, and arteries having the highest heat transfer. Clothing also obstructs heat transfer.

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​Electricity is a key to survival. They allow a nearly instantaneous response to control messages.

Those crucial signals that tell our hearts to speed up when we're in danger come from a mass of cells in our heart called the sinoatrial node, or SA node. It's located in the right atrium, and it controls the rhythm of our heartbeat and the movement of blood from the heart to every other part of our body. It's our body's natural pacemaker, and it uses electrical signals to set the pace. But our pulse isn't the only thing that relies on electrical impulses generated by our cells. Almost all of our cells are capable of generating electricity.

Multiple Choice

What will create static electricity?

• Rubbing a plastic comb on a piece of wool.

• Flipping on a light switch in the classroom.

• Allowing like forces to attract (negative attracts a negative).

• Wrapping a wire around an iron and sending a charge through a wire.

Multiple Choice

Sarah is learning about human harnessed electricity as well as naturally occurring electricity. Sarah comes into contact with many forms of electricity each day. Which is an example of Sarah coming in contact with naturally occurring electricity?

• Sarah quickly walks across the carpet in the socks and feels a small shock on her foot.

• Sarah felt a small sting on her finger when she changed the lightbulb on her lamp.

• Sarah was lightly shocked when she inserted the plug of her lamp in the wall socket.

• Sarah accidently left her curling iron plugged in and burned her hand on the metal.

Multiple Choice

What is the definition of static electricity?

• The tiny particles called atoms are the basic building blocks of all matter

• A complete path around which electricity can flow.

• The buildup of an electricalcharge on the surface of an object. It's called this because the charges remain in one area rather than moving or "flowing" to another area.

• Electricity that is brought under control by people.

Multiple Choice

Static electricity is a

• quick release of energy
• steady flow of electric current
• human-harness
• current used in the house

Multiple Choice

Which is not an example of Human-harnessed electricity?

• hydroelectric dam
• wind mill
• lamp
• lightening

Multiple Choice

Which of the following is an example of a source of human-harnessed (current) electricity?

• Lightning striking a building

• Getting a shock from a doorknob

• A hydroelectric dam

• Socks from the dryer sticking together

Multiple Choice

Which of the following correctly describes one way in which static electricity is different from the current electricity that is used in homes?

• Static electricity is a quick release of energy.

• Static electricity requires magnets and coils of wire.

• Static electricity flows at a constant rate.

• Static electricity always goes in the same direction.

Multiple Choice

Why is current electricity a better source for use in our homes than static electricity?

• Electricity is used where people live.

• Materials must be used to create electricity.

• A steady flow of electric current is needed in our homes.

• Different amounts of electricity are used at different times

Multiple Choice

Jordan rubs her socks along the wool carpet as she walks across her house. She grabs onto a metal door knob. What will most likely happen as she touches the door knob?

• The charge will disappear.

• The chair will repel her.

• She will get a light shock.

• She will build up more charge.

Multiple Choice

When is it easiest for a person to build up static electricity?

• After a rainstorm when they air is warm and humid

• During the winter when the air is dry

• After a lightning strike when the air is full of electricity

• During the spring when the ground is wet