Warm Up #13 What is an electric current?

Lesson 2: Electric Current and Simple Circuits Ch. 9 Electricity Lesson 2: Electric Current and Simple Circuits

Essential Questions What is the relationship between electric charge and electric current? What are voltage, current, and resistance? How do they affect each other?

What is the path to turn on a light? activity Using the following objects how could we light the lightbulb? Let’s test it…… What happened and why did it happen?

Electric current and electric circuits Electric current – the movement of electrically charged particles Electric circuit – a closed, or complete, path in which an electric current travels Electric currents flow in a closed path to and from a source of electric energy

What is electric resistance? Electric resistance – a measure of how difficult it is for an electric current to flow in a material Measured in Ohms (Ω) Good conductors have a low electric resistance Good insulators have a high electric resistance Material’s electric resistance depends on material’s length and thickness Thick material has less resistance than thin material Increasing the length also increases its electric resistance

What is voltage? Voltage – the amount of energy the source uses to move one coulomb of electrons through the circuit High voltage = more electric energy Low voltage = less electric energy

Warm up #14 What do you think Ohm’s Law is?

Ohm’s Law Ohm’s law – a mathematical equation that describes the relationships among voltage, current, and resistance As the voltage of a circuit’s electric energy source increases, the current in the circuit increases too As the resistance of a circuit increases, the current decreases

Ohm’s Law

Ohm’s Law The current through a lightbulb is 0.5A. The resistance of the lightbulb is 220Ω. What is the voltage across the lightbulb?