A simple but cool telescope makes a fun science project that teens and tweens will both find interesting. The materials necessary to make this telescope are as simple as a cardboard tube and both concave and convex lenses. One lens should be larger than the other, reasonably weak and convex (meaning it is thicker in the middle). The weaker this lens is, the more powerful the telescope will be. Tape this lens to one end of the cardboard tube. Tape the smaller lens to the other end of the cardboard tube; this will be the eyepiece lens. The eyepiece lens should be small, powerful and concave in shape (meaning it is thicker around the edges). This project demonstrates how simple it is to zoom in on objects that are far away using a couple of simple lenses.
Anti-bubbles make a cool science trick that can be showed off to friends and family, fascinating both teens and tweens alike. To do this science trick, you need a very clean water surface. You will also need a large clean jar, a bottle of school glue and dishwashing detergent. Place the large jar in a sink and fill it with water until it overflows, with the faucet still running. The constant flow cleans the surface of the water. Add a little dish soap to the jar and stir well, then fill the glue bottle with soapy water from the jar. Now squirt some of these soapy droplets from the glue bottle onto the surface of the water in the jar, by inserting the tip of the glue bottle into the water. The long silvery "worm" that extends beneath the surface of the water, is a long bubble surrounded by air. There will also be bubbles created that literally float and exist below the water, showing how a thin layer of air can be created beneath the surface of the water.
A funny but helpful science project is one that demonstrates how to keep sandwiches as fresh as possible for the longest amount of time. This project experiments with a sandwich that is not stored in a plastic bag, one that is stored in a plastic bag with no seal, one that is stored in a plastic bag with a seal and one that is stored in a plastic bag which is vacuum-sealed. You can also make duplicates of all of these sandwiches and stick them in the microwave or refrigerator for a set amount of time. The sandwiches should all be made out of the same bread and with the same ingredients at the same time. What will be proven is that freshness of bread and food in general is based upon its moisture content. The longer the moisture can be preserved in the food, the longer it takes for it to go stale.