7 Amazing Physics Tricks That Make for Good Party Entertainment

- Make invisible ink from lemon juice

- Learn about surface tension using milk and food coloring

- Make a marshmallow catapult

- The famous Mentos and Coke experiment

There are, of course, many more you can find on the net. You might also want to think up some of your own. 

What are the most popular science fair projects?

Science fairs are great fun for all the family. But there are some timeless classics that tend to be seen time and time again. 

According to sites like sciencing.com, here are some of the most popular science fair projects you might want to create for yourself. 

- Baking soda and vinegar volcano - An absolute classic home experiment and one that is fun for all. 

- Vegetable battery - This is another classic home experiment. Harvest the energy stored in the vegetable's electrolytes to power something. 

- Build a simple wind turbine

- Making art with magnets and iron filings - By sprinkling iron filings on some paper with a magnet underneath, you can make some very interesting patterns indeed. You probably did something similar in your school days.

- Tooth decay experiment - Get some old teeth and submerge them in different liquids (soda, cola, etc). You can then keep a diary of their relative rates of decay. 

What are some fun party experiments?

Here are 7 fun, and easy, physics-related party tricks to impress your guests with. 

1. Place your hands up!

Here is a fun science trick you can do on your friends at parties! It's sure to baffle and entertain in equal measures.

It's also pretty easy to do too. 

- Place your hand flat on your head

- Ask your friends to try and lift it off your head

That's it. While it sounds a little goofy your friends will have a hard time actually doing it.

This is because your hand and arm, are securely attached to your body (hopefully). By trying to 'just' lift the hand they are inadvertently attempting to also lift your entire body. 

Why not also use this experiment/party-trick as an excuse to play some Reef! too? 

2. Nothing shall tear us apart

Here is another fun, and simple, physics-related party trick you can use to confuse your friends. It's also pretty simple to set up and run.

- Find yourself a couple of books

- Weave the pages together as best you can

- Now challenge your friends to attempt to pull the books apart by holding onto their spines and tugging hard

If set up correctly, they should have a very hard time trying to do so. This trick works through the wonderful phenomena of friction.

Since the pages of the book are relatively rough at the microscopic scale, the massive surface is across all pages should provide a huge amount of frictional resistance to being moved apart. 

3. Bouncing batteries trick

This is another fun and simple physics party trick that will astound your guests.

- Find a spent and new zinc battery of the same type

- Ask your friends and family to work out which is which without placing them inside an electronic device

- To win the bet all you need to do is drop the batteries onto a table. The empty one should bounce much higher than the full battery

The reason this happens is that new batteries consist of a layer of zinc wrapped around a brass core. As each battery is used, the zinc slowly turns into zinc oxide. 

Links between the particles within the battery then begin to act more like springs. It's for this reason that an empty battery should be more bouncy than a fresh one. 

4. Pen lid and bottle trick

This is another fun and perplexing physics party trick to play on your friends. 

- Find an open-ended pen lid.

- Place it in the neck of an empty bottle with the open end pointing into the bottle

- Then ask your friends and family to blow the pen lid into the bottle. It seems like a simple task, but the result will confuse many who attempt it.

It should come flying out of the bottle, not into it.

This works by the fact that as someone blows air at the pen lid, air moves around it and into the bottle. This forces out any air already there, ultimately pushing the pen lid out of the bottle!

5. The ultimate spaghetti challenge

There is nothing better than combining physics with food. This physics party trick is a prime example!

- Grab some dry spaghetti

- Challenge your party guests to break one into only two separate pieces only by holding the ends of each piece

- Giggle at them as they fail time after time

Each and every time they will fail to meet the challenge. This is because the first break causes a moving shock wave through the two new pieces.

This results in further breaks occurring leaving your guest with more than two pieces each time they attempt the challenge.

6. Sink into the floor

This is another fun little physics party trick you can entertain your guest with. 

- Have one of them lie face down on the floor with their arms stretched out in front of them. Make sure they stay completely relaxed.

- Lift their forearms up to about their waist level and hold them there for 30 to 60 seconds.

- Then slowly begin to lower their arms towards the floor. This will make the guest feel like they are free-falling straight through it!

This works because the mind and body are tricked into losing their normal sense of space. The sensation won't last too long, but it will freak them out. 

7. Fire and water experiment

Here is another cool party trick you can perform to amaze your guests.

- Grab a glass, a plate (add water to it), some matches and a piece of pineapple

- Challenge your friends to get the water off the plate and into the glass using only the items provided.

There are some rules, however.

1. The glass must be upside down at all times

2. You can't dump the water straight into the glass

So how is it done? Take the pineapple and place it in the plate of water, then take one of the matches and stick it in the pineapple piece.

Light the match and place the glass over the pineapple and match. The glass should then suck up the water from the plate.