It's hard to keep your kids active and engaged during the winter. Since they can't go outside to play, they often end up in front of the TV or on the computer. Keep your children entertained this winter with these three science projects:

1. Erupting volcano

Creating a volcano is a classic activity to do with your kids. Children are always enthralled by anything that erupts, so have fun with your volcano. Instead of simply mixing baking soda and vinegar in a container, use play dough to form a mini mountain with a crater in it. For fun, you can even create little people to put at the bottom of the structure. Once your volcano is completely set up, pour some baking soda inside the crater, then help your child slowly pour vinegar over the soda and watch it bubble down the mountain.

An erupting volcano.Discuss different aspects of volcanoes to turn your science project into a learning opportunity.

2. Mini hovercraft

Everyone is excited by the idea of hovercrafts, so help your child create one of his or her own. All you need for this project is super glue, balloons, an old CD or foam plate and a pull-top lid. To construct your hovercraft, glue the cap over the center hole on the CD, or cut a small incision in the middle of the plate and fix the lid over that. When the lid is firmly in place, blow up your balloon and wrap the end once around your finger so the air can't escape. Make sure your pull-top lid is closed, and fit the opening of the balloon over it. When you release the balloon, it should stay inflated. Grip the sides of the pull-top and open it. This will allow the air in your balloon to escape through the CD's center hole and push the disk up into the air. It should then hover across the floor or other hard surface. Voila! Your own little hovercraft.

"Use mini marshmallows as missiles."

3. Marshmallow catapult

A marshmallow catapult can get a little messy, especially if you have two kids who decide to go to war. However, everyone is sure to have a fun time creating and playing with the catapult. To make your catapults, you'll need wooden skewers, large and small marshmallows, a rubber band, a plastic spoon and tape. Create a pyramid using four large marshmallows and six skewers. Connect three marshmallows with skewers to create a triangle. This is your base - from here, stick a skewer into the top of each marshmallow, and then angle them toward the center, where you'll connect them with your last marshmallow. You now have the body of your catapult.

To finish your creation, tape your plastic spoon to the end of a separate skewer. Place your rubber band around the top marshmallow on the pyramid. Insert your spoon skewer through the rubber band and secure the end of the stick into one of your base marshmallows. Now you can break out your mini mallows and use them as missiles. Have fun flinging (and eating) these tasty sweets!

Do some teaching

Although you're using these projects as a way to keep your children entertained while it's cold, you should also use them as an educational opportunity. For example, if you make a volcano, discuss chemicals reactions and historical volcanic eruptions such as Mt. Vesuvius. For the hovercraft, you can talk about how airplanes and helicopters fly through the air, and the catapult lends itself well to calculating trajectory and discussing force. The main takeaway is to have fun and get creative.