Recent content by Gersty

In a DC motor as I understand it, a current is passed through a coil of wire within a magnetic field. The magnetic field exerts a force on the current perpendicular to the direction of the current. This force causes the coil to spin. Is the coil is between the north and south poles of 2 magnets...

Safety will certainly be a top consideration. The model I have in mind will be small. I understand that the mechanical properties of a material (toughness, strength, ductility, hardness) are the same irrespective of the size of the sample. So if I can successfully test a very small sample of a...

Hello there. I'm a veteran science teacher at the middle and high school level. I've taught a few years of physics and am interested in moving towards engineering. I have looked at a number of available curricula like Project Lead the Way which require a significant investment in time and money...

What is the best analogy to explain electromagnetic fields? I have seen the depictions of em radiation as perpendicular waves. Do we exist in a huge sphere of em radiation in which waves such as cell phone signals and radio broadcasts can be thought of as spherical ripples that emanate at the...

Homework Statement Need to build an electromagnet. Want to build one to work on 12v 7Ah battery with a switch. Needs to be on for up to a minute. Gets pretty hot. Any ideas what components can be wired into circuit and how to control current to retain magnetic field strength but reduce the heat?

BTW: the V1 and V2 in the previous example were numbers I generated to do the math as an example. :)

How about Boyle's Law: P1V1 = P2V2 P1 = 101.325 kPa (STP) V1 = 20 mL V2 = 10 mL P2 = P1V1 / V2 = 20 mL (101.325 kPa) / 10 mL = 202.65 kPa As a practical matter, it remains to be seen how much of a water column we can build and whether or not it will be sufficient to depress the plunger in...

Great idea! Something that could possibly be done in a classroom setting with a number of kids. Need to do some calculations. How tall of a column of water would be needed to produce results in the syringe that would be visible to students?

Thanks for all the input so far.

Interesting. That was sort of another extension of the same unit. I wanted to put a chunk of styrofoam into a water filled vessel and then increase the pressure till the styrofoam deformed/crushed. All to demonstrate the effect of hydrostatic pressure at "crush depth". Still trying to work out...

I'd like to explore water pressure by having students build water towers out of both 2-liter bottles and thinner 1 liter bottles. 1. Assuming they build towers of the same height and fill them with the same type of water, we should see the same water pressure for identical heights within the...

Nope. No pool available. I'm trying to sort of duplicate that demo we've all seen where a styrofoam cup is attached to the outside of a submarine. The sub dives and returns to the surface. When the sub returns to the surface the cup has shrunk due to the pressure at depth. I'd like to build an...

Thanks .Scott for the quick reply. I know fiddling around with pressurized containers isn't the safest. I wasn't sure how high the pressure would need to be to achieve measurable results on something like a styrofoam cup. The demo needs to be visible which is why I thought a large relatively...

I'd like to rig up a glass pressure vessel to see if I could demonstrate crush depth and stuff like that. I was sort of picturing a large small-necked glass jug (think water cooler jug) filled with water and attached to a compressor (or maybe even bike pump?). Styrofoam objects would be...

As the title suggests, I'm looking for a way to explain/describe the EM field to high school seniors. Mechanical transverse waves are easy. But since EM waves travel in a vacuum and require no medium it's hard to form a picture in the mind of the students. What is actually moving?