Science Experiments

Archive for the ‘Science Experiments’ Category

4th and 5th Grade Science Experiments and Science Projects

Question: Ideas on curriculum for an alternative energy course?

I am a high school student and will be taking an independent study course next year. Essentially, I am responsible for designing and carrying out the curriculum throughout the year, with a faculty adviser checking in with me occasionally. I have decided that the subject of my independent study course will be something along the lines of alternative energy or alternative fuels.

Answer: Cool school.

I think that a really interesting perspective for a course on any form of energy is “energy density”.

Next to nuclear, oil is the most “dense” source of energy we have, then we get into things like veggie oil and alcohol, H2 …combustion vs chemical vs fuel cell vs kinetic energy (wind) etcetc. What is the energy density of each form? What are the positives and negatives of each form:

fuel source(animal, vegetable, mineral),
technology( hightech expensive, lowtech cheap, commercially viable!),
byproducts (environmentally benign/harmful, economic … “If I could build a car that would burn water and spit carbon fiber out the tailpipe I’d be richer than Bill Gates!”),
etc?

and finally,

How will those factors affect our response to Global Warming? Will we choose the best choice, a balanced choice, a political choice? It is likely “alternative to fossil fuels” will involve the development of many sources of energy. Will we effectively use the excess energy caused by global warming, or depend on things like geothermal and nuclear out of convenience.

A policy paper that could be presented to government would be a VERY ambitious final objective for the course.

Physics Experiments Ravish High School Physics Project Video on Centre of Gravity

Question: science question about gravity and weight?

so my teacher demonstrated an experiment for us. She held a ball, the same size of a basketball, with a mass of 40 oz, and a regular basketball in each hand. Then she touched both to the ceiling tiles, and dropped them. Both balls hit the ground at the same time. Then she demonstrated by releasing three coffee filters from the ceiling and one coffee filter at the same time. The one coffee filter flipped around and was kind of slow, and the three coffee filters fell in a more straight path, although I do believe both hit the ground at the same time (I’m not sure though, because I couldn’t see). So my question is, why would the heavier objects not fall faster? Does gravity have the same downward push on every object no matter what mass, weight, or size it has? Why did the balls hit the ground at the same time? thank you so very much!!

Answer: Air resistance counters the travel of the bodies falling.

The balls, if they are the same size, have the same air resistance yet the heavier one will actually fall faster because gravity pulls it more strongly to counter that air resistance. The difference was not noticeable but it was there. To really illustrate this, you could use a basketball and a balloon inflated to the same size and shape as the basketball. Gravity pulls less on the balloon than the ball, so the ball falls faster.

Another illustration is two people with parachutes falling. One opens his chute, the other does not. The guy with the open chute has much more air resistance so he falls slower even though the force of gravity pulls equally on them.

The coffee filters illustrated this more clearly. The three combined and the one alone are the same shape and have the same air resistance. Yet, the heavier ones fell faster because gravity pulled them more strongly.

In a VACUUM, we would see different results.

Science / Physics Experiment: Watch to believe!!!! Water level rising against gravity.