[Slickscientist (OP)]

Hi,
Please share your ideas and pictures of practicals that you can do at home (easy or hard) or teach at institutions. They can be for any age group.
Yours sincerely,
Slickscientist.

[Slickscientist (OP)]

You can include pictures too!

[Kryptid]

You mean experiments? I remember performing electrolysis of water for the class in junior high school:

You can avoid the production of chlorine gas by using baking soda as the electrolyte in place of salt.

[Slickscientist (OP)]

Thanks. Unfortunately, I won’t try that, because it is a bit dangerous; on the plus side, you are adding to a science experiment library that will grow and benefit many users and members of the public too!

[Slickscientist (OP)]

So keep those experiments coming😋👍🏽🧪🧪💥
Slickscientist.

[alancalverd]

1. One of the simplest and most instructive is to play with pendulums. You can use all sorts of weights for a bob, the denser the better - get steel nuts or washers from a hardware store or on line - and button thread is a good suspension. Stick a drawing pin in a door frame and devise experiments to investigate the relationship of period to bob mass and string length.

If you have a tall staircase, make a really long pendulum with the heaviest bob you can assemble, and plot the change in direction of swing over an hour. Explain.   

2. Big problem of weighing things in space. It's important if you are, for instance, studying  the growth of mice, or want to crystallise new alloys in zero gravity. Work out how to use a guitar (they always have one on the ISS) to compare small masses.

3. Electrolysis of small quantities of water isn't dangerous. If you collect the gases in a couple of 100 ml plastic test tubes (ridiculously cheap on eBay)  you can get a satisfying pop from igniting the hydrogen, and watch a glowing ember re-ignite in the oxygen. You almost certainly have some old 5 or 12 volt DC chargers lying around the house.  The stoichiometric gas evolved from electrolysis with AC is interesting: it burns by itself since it contains both hydrogen and oxygen in optimum proportions, so with a bit of cunning you can make a flame that continues to burn in a sealed container.

[Slickscientist (OP)]

Thank you!

[alancalverd]

Happy to help! Once you have explained the rotation of the plane of swing of a long pendulum, have a careful look at a house fly with a magnifying glass. Some insects have four wings, but diptera (house flies) have the second pair reduces to a stalk with a knob on the end, called halteres, that vibrate very fast in flight. AFAIK these provide an artificial horizon or turn rate indication, as in an aircraft.   

[Slickscientist (OP)]

Happy to help! Once you have explained the rotation of the plane of swing of a long pendulum, have a careful look at a house fly with a magnifying glass. Some insects have four wings, but diptera (house flies) have the second pair reduces to a stalk with a knob on the end, called halteres, that vibrate very fast in flight. AFAIK these provide an artificial horizon or turn rate indication, as in an aircraft.

👍

[Slickscientist (OP)]

This is a good one for any children out there who want to have some fun, but learn how it happens in a more detailed way...

[alancalverd]

Good one - and a very important phenomenon in meteorology and aviation!

Also worth a try: take two identical clean cans (baked bean cans, throughly scrubbed out or cleaned in a dishwasher. Nearly fill one with hot water and the other with water at room temperature, and put them both in the freezer. Look in every hour. Which one freezes first?  Try hot water from the hot tap, half-and-half from a freshly boiled kettle and the cold tap, and the cold tap.

It's a classic experiment recorded by Charles Darwin and later by schoolboy Erasto Mpemba, after whom the effect is popularly named. EM never became quite as famous as CD but he did go on to pursue a career in physics.

As an aside, I don't believe the reports of Mpemba's original experiment are correct.

Worth an investigation and a discussion - folk have argued about this for years!

[Slickscientist (OP)]

As an aside, I don't believe the reports of Mpemba's original experiment are correct.

Worth an investigation and a discussion - folk have argued about this for years!

Should I make a page for you to talk about it; you look very keen on the subject, but you can't find anyone to debate about it with you(I think).

If anyone is too lazy or bored to make a new topic about something, come to me and I ill do it for you. (I cost £20 per page-just joking!).