Science Projects And Inventions

YOU NEED

• A hammer
• A ruler
• A loop of string
• A table

  Make an odd structure and make it balance on the edge of a table. Take the length of string. Turn the string into loops so that it looks like a bracelet.   The illustration reveals how the string bracelet can hold on to the end of a ruler which in turn is attached to the end of a hammer handle. Now put the other end of the ruler on the table edge as in the illustration. You will notice the structure will stay balanced though it seems that the heavy head of the hammer will make it drop to the floor. HOW DOES IT WORK? What actually happens is that centre of gravity of the system is shifted to a point slightly under the edge of the table by the heavy head of more...

YOU NEED

• • A book
  • A piece of wooden board
  • Four pencils

  Place a book on a sloping wooden surface and push it, you will find that it moves slowly. Now place four pencils under the book, you will find it moves more easily and smoothly.   HOW DOES IT WORK? The wooden surface provides resistance to motion and slows the movement of the book. Placing four pencils under the book reduces friction and the book moves easily.

YOU  NEED :

• 18  inch length electrical wire
• A small bulb
• A holder
• Battery

  Connect two 18 inch lengths of electrical wire to the connectors of a bulb holder. Set a small bulb in the holder. Connect the other ends of the wires to the terminal of a battery with clips. As you complete the connections, the bulb will light up because the circuit is complete.   HOW DOES IT WORK? Current flows from the positive terminal of the battery towards the bulb.  Inside the bulb it flows through the filament towards the negative terminal of the battery. Since the path is not broken, the circuit is complete and the bulb lights up.

YOU NEED: • Two paper clips • A magnet It is easy to hang a paper clip on the bottom of a magnet, as in the illustration. With a little more care you can suspend a second clip under the first. Once the two paper clips are connected, carefully lift away from the magnet the top clip of the chain. Once its is away from the magnet, will the second clip drop free? Interestingly, it will not! More powerful magnets will support a chain of three or more paper clips.   HOW DOES IT WORK?  In most objects the atoms have a tiny amount of magnetic force, but because their poles are not aligned with each other, these forces cancel each other out. In a magnet many more atoms are aligned, so they work together to create a greater force overall. A magnet also has the more...

YOU NEED: • A banana • A spring weight measure   The fact that weight is a force can be proved by weighing an object such as a banana, with a spring balance. Weigh it in air and re-weigh it submerged in water. You will find the banana weighs less in water. HOW DOES IT WORK? Since water exerts an up-ward thrust it reduces the pull of gravity on the banana. Therefore weight of water displaced by the banana equals the amount of up thrust exerted by the water which is why it weighs less.

YOU NEED: • Apiece of cardboard • Two pins • Some thread • A wooden board   On an oddly cut piece of cardboard punch three holes in three corners. Mount the shape on a board with a pin weight to a piece of thread. Hang the weight from the pin and draw a line along the thread. Repeat the procedure with the other holes. The point of intersection of the three lines is the centre of gravity.

YOU  NEED :

• Two pencils & Two Glasses
• Some wire
• Two strip
• 9 volt battery

  Sharpen two pencils at both ends with a long lead at one end of each pencil. Attach a wire to each pencil by wrapping its stripped ends around the long lead on one end. Connect the wires to a 9 volt battery. Now place the pencils in a bowl of water and add a tablespoon of vinegar to speed up the electrolysis. Take two glasses and place them, one over each pencil. At this stage electrolysis is breaking up the components of water and collects as hydrogen gas on the pencil connected to the negative terminal and as oxygen gas on the other terminal. Remember water contains twice as many hydrogen atoms as oxygen atoms.