The Electric-Circuit Interaction U1C2A4 The Electric-Circuit Interaction

2. How many connections are there to each element in the circuit? Exploration #1 2. How many connections are there to each element in the circuit? Answer: Two Connections.

3. When does an electric-circuit interaction occur? Answer: An electric-circuit interaction occurs when a source of electric current (ex: battery/cell) is connected in a COMPLETE LOOP with conducting wires to an electrical device (ex: light bulb).

Exploration #2 4. In order for an electric-circuit interaction to occur, the type(s) of materials that must be included in the circuit is (are) metal. The evidence is that when we placed metals objects within the loop the bulb lit up, but when we placed nonmetal objects such as paper and plastic, the bulb did not light up.

6. Unscrew one of the two light bulbs from its socket 6. Unscrew one of the two light bulbs from its socket. Leave the other bulb alone. What happened to the other bulb? Answer: it goes out!

8. Unscrew one of the two light bulbs from its socket 8. Unscrew one of the two light bulbs from its socket. Leave the other bulb alone. What happened to the other bulb? Answer: it remains lit!

9. Why do you think the result for Question 8 was different from the result for Question 6? Answer: In a parallel circuit (Q.#7), each bulb has its own separate loop to the cell and electricity still flows in this separate closed circuit.

9. Why do you think the result for Question 8 was different from the result for Question 6? Answer: However, in a series circuit (Q.#5), the bulbs are in a single loop and electricity doesn’t flow when the circuit loop is is open (one bulb unscrewed).

Exploration #4 10. Is the bulb in this two-cell and one-cell bulb circuit brighter than, dimmer than, or equally as bright as the bulb in the one-cell, one-bulb circuit in Exploration 1? Answer: Brighter.

11. Is the bulb in this two-cell and one-cell bulb circuit brighter than, dimmer than, or equally as bright as the bulb in the one-cell, one-bulb circuit in Exploration 1? Answer: it’s brighter.

12. Write your conclusion for this exploration by answering the following question in a complete sentence. If the number of cells in the circuit increase, what happens to the brightness of the bulb? Answer: As the number of cells in a circuit increase, the brightness of the bulb increases.

13. What is your hypothesis about the relationship between the number of cells and the amount of electric current? Answer: The more cells, the greater the amount of electric current because when we hooked up two cells and one bulb in a series circuit, the bulb glowed lighter.

#14 98.2 mA 85.5 mA 70.3 mA 50.1 mA

increases as the number of cells increase from 1 to 2 to 3 to 4 , the amount of electric current increases from 50.1 mA to 70.3 mA to 85.5 mA to 98.2 mA.

Let’s Review

Make Sense of Your Ideas

power source (cell) electrical device (light bulb) wires

by wires in a complete loop

What is the evidence that an electric-circuit interaction has occurred? LINK change in illumination- when the light bulb is glowing (on) electric current is flowing through the circuit

When does an electric-circuit interaction occur?

the electric current stops flowing so the electrical device turns off

What happens when there is a break in the electric-circuit?

What happens when there is a break in the electric-circuit?

5. What variable or variables can influence the electric-circuit interaction? What is your evidence?

variable = # of light bulbs bulbs brightness

variable = how devices are connected series circuit or single-loop circuit parallel circuit or multi-loop circuit

variable = how devices are connected In a series circuit- unscrew 1 bulb then they all go out In a parallel circuit- unscrew 1 bulb then the others stay on

cells  brightness cells electric current variable = # of cells 70.3 mA 50.1 mA cells  brightness cells electric current 85.5 mA 98.2 mA

Exploration 3- variable was adding bulbs to circuit with one cell 5. What variable or variables can influence the electric-circuit interaction? What is your evidence? Exploration 3- variable was adding bulbs to circuit with one cell bulbs brightness Exploration 3- variable was changing how we connected the bulbs (series and parallel circuits) In a series circuit- unscrew 1 bulb then they all go out In a parallel circuit- unscrew 1 bulb then the others stay on Exploration 4 & 5 adding cells to a circuit with 1 bulb cells  brightness cells electric current (amperes)

#6 Holiday Lights Read and answer carefully. This will be graded for correctness.

#7 Lamps at home Read and answer carefully. Be sure to explain how you know.

Answer the Key Questions Use the back of your paper to fully answer the key questions.

Key Question #1 What are the defining characteristics of an electric-circuit interaction? Summarize your answers to Making sense of your ideas #s 1-4

Key Question #2 What are some variables that influence the electric-circuit interaction? Use making sense of your ideas #5 to answer this question (hint- there are THREE (3) variables)

How do batteries generate electricity?

Video Quiz!

Video Quiz Answers C B A D

Stop here and use a red pen. We will now correct your answers. Use red pen or a pen of a different color than your answers only.

Make Sense of Your Ideas

Type A – series Type B – parallel

Parallel circuit because if I turn 1 lamp off, the other stays on.

Key Question #1 What are the defining characteristics of an electric-circuit interaction? Summarize your answers to Making sense of your ideas #s 1-4

Key Question #1 (Summarize #s 1 & 2)

Key Question #1 (Summarize #s 1 & 2) An electric-circuit interaction occurs when a power source is connected to electrical device by wires in a complete loop

Summarize # 3

Key Question #1 (Summarize # 3) if electric current is flowing then the electrical device is working/on (ex: light bulb is glowing)

Summarize #4

Key Question #1 (Summarize #4) when there is a break in the loop/circuit the electrical device will stop working because the electric current is NOT flowing

Re-read Make Sense of Your Ideas # 5 Key Question #2 Re-read Make Sense of Your Ideas # 5

series or parallel?

series or parallel?

Look back over Explorations 3, 4 and 5

variable = how devices are connected series circuit or single-loop circuit parallel circuit or multi-loop circuit

variable = how devices are connected In a series circuit- unscrew 1 bulb then they all go out In a parallel circuit- unscrew 1 bulb then the others stay on

cells  brightness cells electric current variable = # of cells 70.3 mA 50.1 mA cells  brightness cells electric current 85.5 mA 98.2 mA

Key Question #2 The number of cells The way you hook up electrical devices to an electrical source

Grade Yourself 3 points for labeling the parts in the pictures from exploration 1 and 3. 5 points for answering the key questions completely and correctly. 2 points for answering #6 (holiday lights) and #7 (lamps) of making sense of your ideas correctly. Write the total out of 10 points at the top of the front of the record sheet.

Electric-Charge vs. Electric-Circuit

The way you hook up electrical devices to an electrical source series parallel

The way you hook up electrical devices to an electrical source Change the way you hook up the wires (series or parallel circuits): EVIDENCE- in a series circuits if you unscrew 1 light bulb, the other light bulb goes out…..in a parallel circuit if you unscrew 1 light bulb, the other light bulb stays on

increasing the number of cells increases the amount of electric current flowing in the circuit EVIDENCE = the light bulb glows brighter, mA increased