Ohms Experiment Help for Science Fair | ScienceBuddies.org

  • Thread starter Thread starter justinjay24
  • Start date Start date
  • Tags Tags
    Experiment Ohms
Click For Summary

Discussion Overview

The discussion revolves around a student's confusion regarding an Ohm's law experiment for a science fair project. Participants explore the methodology of measuring resistance, voltage, and current in a circuit using a battery and an ohmmeter, addressing the student's difficulties in obtaining varying results based on different wire gauges.

Discussion Character

  • Exploratory
  • Technical explanation
  • Homework-related
  • Debate/contested

Main Points Raised

  • The student reports that measurements of resistance (Ohms), DC, and AC are consistently the same, which raises questions about the experimental setup.
  • Some participants suggest focusing on measuring the current (amps) through different wire gauges rather than just resistance.
  • A participant advises checking the resistance of the wires using a voltmeter and provides the formula V=I*R to relate voltage, current, and resistance.
  • Another participant questions the appropriateness of using an ohmmeter with a power source, indicating that this may lead to inaccurate readings.
  • Some participants express skepticism about the feasibility of obtaining accurate resistance measurements with an ohmmeter for various wire gauges.
  • There is a suggestion to draw a circuit diagram to clarify the setup and methodology being used.
  • The student considers changing the project focus from comparing resistance to comparing voltage or current due to the consistent readings obtained.

Areas of Agreement / Disagreement

Participants express differing views on the correct methodology for the experiment, with some emphasizing the importance of measuring current and resistance accurately, while others question the use of the ohmmeter in the current setup. No consensus is reached on the best approach to take.

Contextual Notes

Participants note potential limitations in the student's experimental design, including the use of an ohmmeter with a power source and the accuracy of measurements at low resistance values. These factors may affect the reliability of the results.

justinjay24
Messages
3
Reaction score
0
Alright, I'm a student and doing a science fair experiment for a little extra credit. Here's the link to where I found it online. http://www.sciencebuddies.org/mentoring/project_ideas/Elec_p019.shtml?from=Home

I don't get it, at all. I just tried it and every time I measured it the Ohms, DC, and AC were all the same. I don't know what to do, I got about a week left to do this, and I'm completely lost. Anyone else have an idea? This just doesn't make sense to me...:frown:
 
Engineering news on Phys.org
What specifically don't you understand? I'll try to make it clear to you.
 
Last edited:
Alright, well, here's what I did...

I took a 6v battery, took a wire with alligator clips at both ends and hooked it on the battery and the ohmeter. Then, I took another wire, hooked an alligator clip on it, and connected it to the empty spring on the battery. Then I would complete the circuit with other wires. However, whenever I did this, even with completely different gauges and length, all the results were the same, and I thought they should be different.

Any ideas?
 
Don't measuring how many volts are in the entire circuit. What you should be noticing is the change in how many amps go through the different gauges of wire. I am assuming you have a volt meter. First check the resistance in different gauges of wire using your volt meter, or go to http://www.powerstream.com/Wire_Size.htm" which can tell you the ohms in a wire per 1000ft. The amount of current you will get will depend on the voltage of the battery and the resistance in the wire. An equation that will be very useful for this experiment is
V=I*R
V=voltage
I=current
R=resistance
Example- Say you use your 6 volt battery with a wire that has 2ohms of resistance. Then you would say the current is 3 amps because, (using algebra) 6 volts/2ohms=3amps.

To sum it all up, what this project looks like its looking for is the resistance in different gauges of wire.

Hope this helps
 
Last edited by a moderator:
Alright, I think I'm going to change my project from comparing resistance to comparing volts, or amps. Because like I said, every time I would hook up the wires, the ohms would be the same.

So thanks!
 
Why are you using an ohmeter with a power source (battery)? This is not the way the ohmeter is meant to be used. I'm not sure you understand what you are supposed to be doing. And I don't think that you will have any better luck measuring volts or amps because resistance is simply a ratio of volts/amps. Can you draw a circuit for us?
 
Measure the resistance in the wires themselves not the battery.
 
Hover, he is not going to get a usable reading measuring the resistance of various gauges of wire with an ohmeter. It is unlikely he has access to a meter that is able to measure that accurately at very low ohm readings.
 
Wow. I just read the link he provided in the first post. They are instructing him to wire the ohmeter in series with the circuit. There is nothing else in the circuit. Just wire, alligator leads and the ohmeter. Who could expect results that make any sense with that?
 
  • #10
Wow is right.
That's horrible.
 

Similar threads

What Happens When AC and DC Signals Interact in Audio Circuits?
  • · Replies 13 ·
Replies
13
Views
3K
How does AM broadcasting/receiving work + a project for HS students?
  • · Replies 20 ·
Replies
20
Views
3K
Electrical Cheap Way to Create AC Current For Breadboard At Home?
  • · Replies 8 ·
Replies
8
Views
3K
Home experiment - 'seeing' magnetic lines of force?
  • · Replies 6 ·
Replies
6
Views
2K
Ionic thruster high school science project
  • · Replies 2 ·
Replies
2
Views
962
Magnetic wire or enamel coated magnetic wire?
  • · Replies 4 ·
Replies
4
Views
2K
TDS2004B Oscilloscope Accuracy Determination
  • · Replies 2 ·
Replies
2
Views
2K
Schools What are some good science fair project ideas or resources?
  • · Replies 5 ·
Replies
5
Views
5K
Stephan-Boltzmann Law Help for Science Fair Project - Needed Now!
  • · Replies 2 ·
Replies
2
Views
3K
Experimenting with 24VDC to AC Generator Output
  • · Replies 4 ·
Replies
4
Views
2K