Invention conventions are held to enable kids to put their creativity and imagination to productive use. 3rd graders are definitely able enough to come up with and to execute some good invention ideas. They can be simple, complex, useful, useless, silly, outrageous, and even downright bizarre! What matters is that they use their heads and their hands to come up with something that they're proud of. So, without wasting any more time, let's go through this Buzzle article which has some interesting 3rd grade invention ideas that you might want to use.
Many people have an annoying habit of squeezing the tube of toothpaste from anywhere in the middle. This results in a lot of wastage of perfectly usable toothpaste at the bottom of the tube, not to mention the number of times the tube needs to be picked up because it falls off balance from the stand. So, since the people won't change their habits, you can put an end to this annoying situation by making a toothpaste squeezer. It is nothing but a small panel attached to the tube, right at the bottom. This panel should be on both sides, the front and the back of the tube, like a clip. Also, make sure that you can move it upwards on the tube. This way, when someone squeezes the tube, the clip moves upwards and no toothpaste is left behind in the tube.
Rake with Scoop
How many times have you been asked to rake the dried leaves off the lawn and cringed at the thought of it, only to ultimately give in to your mom's constant nagging and doing the job. And how many times have you cursed because of the numerous times you've had to bend down to pick up the leaves and scoop them. How about inventing a simple device that will help you to rake up the leaves without the bending? Simply have a scoop attached to your rake. You can have one that closes at the pull of a string (using a pulley) and tie this to the top of the handle of the rake. So, when you're done raking, simply pull the string, open the scoop, collect the leaves, and close the scoop and go dispose of the leaves.
Wallet for the Visually Impaired
Here's a really interesting 3rd grade invention idea. You can design a wallet for the visually impaired. This wallet can be made of an eco-friendly material and can have pockets that are specifically for the different denominations of currency notes. These denominations can be marked by using the Braille numbers and having markers at the top of every pocket. You can also have a pocket for change denoted by the Braille symbol for coins.
Here's an invention idea for all the little girls hoping to make it big at their invention convention. I'm sure you've heard of mood rings. They're the rings that change colors according to the mood of the wearer. What you can do for your invention is, get your hands on the same material that a mood ring is made of (liquefied thermotropic crystals), which might be available at a jeweler, and use it to cover a headband that you wear. This headband will change its color according to your mood, based on the change in your body temperature.
You can use any of the invention ideas mentioned above to fair reasonably well in your school's invention convention. They're fairly easy to make and are quite useful too. Let us know if you have any more creative and innovative ideas. We'd love to hear from you! Good luck and happy inventing!