Resistance

Starter What do you think we mean when we talk about resistance in a circuit. Write your ideas in your book.

Resistance The resistance of a conductor is a measure of how easy or hard it is for a current to flow through it. In today’s lesson you will be measuring the resistance of different lengths of wire.

Make a prediction! Write the title “Measuring Resistance” in your book…this is the beginning of your first lab report! Make a sub-heading “Prediction” Under this you need to make your own prediction – what do you think will happen in the experiment? How do you think the resistance will change as we change the length?

Equipment list Make a new sub-heading “Equipment list” Make a list using bullet-points of the equipment we will use: Resistant wire Metre ruler Connecting wires Multimeter Crocodile clips This is what we will measure the resistance of. To measure the length of the wire. To connect the multimeter to the resistant wire. To measure the resistance. To connect the wires together

Circuit diagram Make a sub-heading “Circuit Diagram” Draw a circuit diagram: Ω

Procedure Make a sub-heading “Procedure” Measure and cut 100 cm of resistant wire. Set the multimeter to the 200 Ω setting. Plug connecting wires into “COM” and “V Ω mA”. Complete the circuit using connecting wires. Record the value of resistance in the results table. Repeat the experiment for different lengths of wire.

Results Table – Make a sub-heading!!  Length of wire (cm) Test 1 (Ω) Test 2 (Ω) Average Resistance (Ω) 20 40 60 80 100

Example Results Table – Watching out for errors! Length of wire (cm) Test 1 (Ω) Test 2 (Ω) Test 3 (Ω) Average Resistance (Ω) 40 3.1 3.4 3.2 80 5.9 6.0 6.2 120 9.3 9.2 9.0 160 12.4 12.2 12.3 200 15.7 15.4 19.2 15.6

Make a sub-heading “Graph” We will plot a graph with “Length of Wire (cm)” on the x-axis and “Average Resistance (Ω)” on the y-axis.