The nicest way is to use a Google account [free] , and upload your photos to Google+. If you use the standard filesize, all pix are free to store. Then use the Google+ Slideshow Feature, as you use the Google Cast Extension casting function.
Explain that water is made up of tiny particles, called molecules, which are too small to see. These particles are always moving, even in very cold water. Since water molecules move, the molecules help mix the food coloring. However, the color mixed faster in the hot water than it did in the cold.
If there were no membrane then the dissolved substance would diffuse throughout the mixture. If you put a membrane there then the same idea works but this time it is only the water that can move. So the water moves through the membrane until the same concentration of water molecules appear on each side.