## HSC physics 2009 Q19 topic: projectiles

Answering a different sort of projectile motion question

## How Well do you Know – induction

How well do you know electromagnetic induction, Faraday’s Law and Lenz’ Law?

## How well do you know Special Relativity?

In this video I take you through a number of multiple choice questions to test your understanding of the basics of special relativity and its consequences

## How Well do you know Projectiles?

In the first of a weekly series, I go through a variety of multiple choice questions, in increasing difficulty that assess your understanding of projectile motion.   I then go through the solution as well as showing why the other alternative responses are incorrect

## Color changing milk experiment

Science Night The Explosion of Colors Experiment – This experiment is a lot of fun. How does it work? Milk has fat in it and the food coloring floats on top of the fat. The fat is all connected with bonds. When you add the dish soap to the milk, the fat separates and moves making the colors explode!

## Amazing Melting Ice Blocks Experiment

Totally Awesome to Watch!!! This is one of the most striking science demonstrations we have seen in a long time. Place an ice cube on each of these two identical looking black blocks at room temperature. One ice cube instantly begins to melt and is totally gone in about 120 seconds while the other ice cube shows no evidence of melting.

## Skittles Experiment

Colorful candies like Skittles are made with FD&C dyes, sugar and other substances. By adding hot water with the skittles it starts to release the dyes as you can see here with the experiment.   Try different candies to see if you get the same results. Or start the candy in the middle of the plate to see what happens. Best part is you can still eat them.

## Floating Paper Clip Experiment

How is this possible? With a little thing we scientists call SURFACE TENSION. Basically it means that there is a sort of skin on the surface of water where the water molecules hold on tight together. If the conditions are right, they can hold tight enough to support your paper clip. The paperclip is not truly floating, it is being held up by the surface tension. Many insects, such as water striders, use this “skin” to walk across the surface of a stream.

## Drops of water on penny

How Does It Work? Surface tension gives water some amazing properties. The cohesion and surface tension of water becomes apparent when the drops of water you add to the penny reach the penny’s edge. Once the water has reached the edge, you begin to see a bubble or dome of water forming on top of the penny as you can see here in the video. The bubble shape is a result of the water molecules clinging to one. I was able to get 30 drops on a penny. Let me know how many you were able to do?

## Iodine Clock reaction

First you Make two chemical solutions and mix them together. Wait a few seconds, then wow! It will suddenly change colors. This is the famous iodine clock reaction in an easy-to-use kit. Change the concentrations or temperature and change the delay for the color change. Adult supervision is Required.

The Tornado tube Connector is a plastic adapter fitted for two plastic soda bottles to be held together to create a vortex within one of the bottles. It works by flipping and then spinning the bottles in such a way that the water is now in the top bottle and the air begins to replace the water in the top bottle in a vortex shape.

## Shooting Pepper

See how soap breakdowns the surface tension of water.

## Aluminum boat buoyancy challenge experiment

Take the Aluminum boat buoyancy challenge. Start with a 4″ by 4″ piece of aluminum foil. Then use that piece to make a boat that will hold the most pennies as possible without sinking. See which designs hold the most. My niece Amber was able to hold 20 pennies. This challenge will make you explore how the size affects how much weight they carry and how this relates to the density of water. Try this with salt water to see if you can hold more pennies?

## Surface Tension Bubble Breaker Experiment

Why a pot of boiling water will not boil over when pasta is added if olive oil is added to the water beforehand? Water molecules are polar and they strongly attract one another at the surface of the water. This makes the surface harder to pierce or expand. Pure water doesn’t foam when it boils, because it’s hard to stretch the surface out to make bubbles. The scientist is called “surface tension”.   Now drop some pasta in the pot. As it cooks, organic materials are released into the cooking water. Some of these organics materials have hydrocarbon parts that…

## Magic Water Flower Experiment

Your Magic Water Flower is powered by scientific phenomenon called Capillary action. Thanks to Capillary action, paper absorbs water very rapidly. When the paper gets wet, it swells which causes the folded petals of your Magic Water Flower to open up.   So what does all this have to do with your Magic Water Flower? Paper is made of tiny wood fibres which are tightly interwoven providing amazing strength and a beautiful writing surface. Even in high quality paper, there are billions of tiny little gaps between the fibres.   When paper comes into contact with water, the amazing power…

## Soap Powered Boat Experiment

The movement of the soap powered boat has combination of three principles.   Surface Tension 1) All liquids have a little thing scientist call surface tension! Water molecules are strongly attracted to each other and stick close together. This creates a strong but flexible “skin” on the water’s surface, which is able to support small insects and materials like our paper boat on their surface.   2) Isaac Newton’s third law of motion says for every action there is an equal and opposite reaction. The movement of the soap provides a ‘pushing force’ backward into the water surface as the…

## Water Bottle Flip physics

Angular momentum + Centrifugal force + water bottle= SUCCESS   I’m sure any kid in school that doesn’t live in a snow cave, has try the water bottle challenge.   Also known “The flip,” as it will henceforth be known, all begins with a flick of the wrist, generating a specific force called angular momentum,   Angular momentum is very similar to the classical sense of momentum, where an object moving will not change its motion unless acted upon by another force. With angular momentum, the same concept is applied to rotation.   As centrifugal force keeps the water at…

## Cartesian diver Experiment

The Cartesian diver, named after French philosopher and scientist René Descartes, works because of several factors.   When you squeeze the bottle, the pressure on the water pushes on the pocket of air inside the pipette. You can see the level of the water in the diver rise as you squeeze the bottle. As the water level inside the diver goes up, it compresses the air above it into a smaller space. This demonstrates that gases are considerably more compressible than liquids.   As the water level rises in the diver, it becomes less buoyant and the diver sinks. As…

## Whiskey & Water Experiment

Most people think of this as a trick, but their is Science behind this. Whiskey is lighter than water (the better the whiskey, the better this works). The lighter whiskey will slowly trickle upwards to the top of the water’s shot glass, while the water trickles down. It’s a really neat looking effect! After 10 minutes(my video was fast forward), the two drinks will have completely swapped places.