# Tag Info

95

There is no tidal bulge. This was one of Newton's few mistakes. Newton did get the tidal forcing function correct, but the response to that forcing in the oceans: completely wrong. Newton's equilibrium theory of the tides with its two tidal bulges is falsified by observation. If this hypothesis was correct, high tide would occur when the Moon is at zenith ...

18

The picture of high tides on opposite sides of the Earth with a period of about 12 hours (actually 12 hours 25 minutes, due to the rotation of the Earth) is an oversimplification. It's just a starting point. Tides would behave this way in the limit of an all-water Earth with ocean depth so great that it had no effect on the surface wave. But the Earth has ...

18

One that jumps to mind is Hooke's law (extension of a spring). Hang a spring or thick elastic band and load it with increasing weights. See that extension is proportional to load at least initially. A natural extension of that is to also measure oscillation time/frequency. Another one would be Archimedes principle, and play with floating/sinking different ...

7

Some basics experiments: Freezing of water. The parameter is the temperature. After that, you could add some salt in the ice. You can show that the mix ice/water have a lower freezing temperature than just water. So you can observe T_fusion as a function of the mass percentage of salt in your mix. You can do the same with other stuff : alcohol, vinegar, ...

6

You could see how the mass of an object affects how quickly it falls by dropping balls of various masses (tennis ball, orange, melon, whatever) from a specific height and timing which of these falls fastest. This will allow you to draw the conclusion that the time it takes an object to fall from a given height is independent of the mass. You could also ...

4

There are so many things you could do. Here are just two: Put things on a microwave. See how hot they get after 1 minute on high. Does it matter whether you have one, two, three cups. Does adding salt to the water make a difference. How about vegetable oil and water - do they heat at the same rate. What if you add sugar. Does it heat the same when you ...

3

I recommend two resources: Feynman's original book called Quantum Mechanics and Path Integrals. This contains most of the prerequisites in the first two chapters, but you will need some maturity to get through them. A. Zee's quantum field theory book Quantum Field Theory in a Nutshell for its friendly chapter on them.

3

Unlike sea tide, which is quite complex, as other answers explain, the solid (not-so-solid for this part) Earth tide tends to be simple and the first-order picture can be reasonably approximated by the "bulges" metaphor mentioned in the question. Solid earth tide has an amplitude of ~1 ft typically and it can be safely ignored in most situations, including ...

3

Range of a projectile as a function of launch angle is simple and has a nice "right answer" that you can compare with. I'd start with the simplest: "throw this ball as hard as you can straight forward, then straight up, then at some different angles". Measure the distances. If you can do it easily, set up a video camera and play around with measuring the ...

3

To study the precise mathematical formulation of path integrals, you actually need probabilistic tools. The path integral is a stochastic integral with suitable measures, such as the Wiener measure associated with brownian motion. The ideas used by physicists are very useful, but not always mathematically accurate, and rely more or less on justification by ...

3

There are a lot of good suggestions here, but I think some of them are missing the crux of the question; the student needs to learn to prove or disprove a hypothesis by varying parameters. For that, you might need several hypotheses - demo experiments are not going to help for the reason they haven't worked so far; they show a rule working, rather than the ...

3

As someone who has a fondness for atmospheric physics, I do enjoy the "cloud in a bottle" demonstration. I'm sure children would enjoy seeing a cloud in a bottle too. All you need is: A 2 litre plastic bottle A small amount of water A match It demonstrates how a cloud forms by the process of adiabatic expansion and evaporates by adiabatic compression. ...

2

I'm assuming the daughter of a chemist has been introduced to the non-Newtonian fluid experiment? "struggles to appreciate how changing parameters in an experiment can be used to prove or rule out a hypothesis" = doesn't understand the importance of the control group? Has the scientific method been gone over yet? This may be a little advanced for 3rd ...

2

This question is a bit open-ended so I'm not sure if it's appropriate for this site, but I'll try to answer it anyway. What you're talking about most likely is developing so called 'maturity' in math and physics. This isn't really a well-defined concept, but most people have an intuitive sense of what it means; if you have maturity in physics this most ...

1

how is the detailed connection between the statement that the length measurement has to be simulanous and the quoted derivation? Sally didn't measure a length, she measured a time and, from that, calculated a length. Both Sally and Sam agree that their relative speed is $v$ so Sally can calculate the distance between the ends of the platform by ...

1

Feynman's path integral formulation is closely related to the action principle of classical mechanics, which relies heavily on the calculus of variations. You need to learn, essentially, how to minimize a functional. Prerequisites are pretty much just calculus (multivariable, hopefully), as well some classical mechanics to understand the motivation behind ...

1

How big is an atom? Fill a sink with water. Find a chemical which, when dropped into water, forms a contiguous floating disk. Drop one drop of this chemical into water. Measure volume of drop and area of floating disk. This provides upper bound on the size of an atom. Falling speed versus mass/shape Drop a book and a piece of paper at the same time. Book ...

1

The specific problem of your location is answered partially in the comments. I suppose it is the six hours that is problematic for you. Edit after reading main answer that there are lots of bulges due to the ocean landscape boundary conditions and fluid mechanics. What does it mean that a bulge, a high twelve foot tide, comes from the west , lets say at ...

1

Yes, the earth has high tides on opposite sides. That is why high tides come about 12 hours apart. The timing of tides at nearby places is very dependent on local landforms. You can probably see a nice gradation of tide time if you look at the towns between Holyhead and Whitby. The delay may be different for high and low tides. The tides get very ...

1

My suggestion would be to simply show him a picture or better yet animation of how the earth moves around the sun. There are also a number of interactive gravity simulations like "Universe Sandbox", that let you play around with gravity. If the question is "why?" rather than "how?", then I would go with: No one really knows, but physicists (or some more age ...

1

I'm not sure if you're talking about probabilities here but if you are then I found some problems online: 1) In how many ways can 8 people line up for concert tickets? 2) There are 5 women running a race. How many different ways could 1st, 2nd, 3rd place finishers occur? 3) There are 13 members on a board of directors. If they must form a subcommittee ...

1

Quantum Mechanics and Path Integrals: This is a book every physicist, or student of physics, should study. Here the author describes the principle of action in quantum physics. It is not a minimum action principle, like in classical mechanics: you can, however, derive the classical minimum principle from it, in the classical limit. Why is this important? ...

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