Joining a homeschool co-op group is a great way to meet other homeschooling families and share resources and ideas. These groups generally meet once a week to do group activities or go on field trips. Oftentimes, parents in the co-op will take turns teaching workshops or classes in their own area of expertise to all of the children in the co-op. If there is a special area of interest (such as science) in which none of the parents feels comfortable teaching, the co-op will decide to hire an outside teacher to provide instruction for the group. In this way, the families share the cost of the lessons, thereby providing a much more affordable alternative to private tutoring.
If there are no vacancies in a homeschool co-op in your area (group size is often limited in order to preserve the intimate, family atmosphere that many homeschooling families desire), and you don't want to start one, yourself, you could look for someone offering classes, independently, in your area. You could also hire a private tutor, but this could be quite costly. Depending on where you live, the going rate for tutoring ranges anywhere from $30 per hour to over $100 per hour. Group classes tend to be more affordable.
If you do not want to have other people teach your child(ren) science, or you cannot find a suitable group or class, there are many excellent science books and science curriculum resources available for all ages and levels. Many of these have step by step instructions for doing experiments and activities at home. If you want to plan your own program, decide which topics you want your children to study first and head to your local library or bookstore. choose one or two reference books on the subject (for you and/or for your children). Do not feel that you need to look through every book that there is on the topic. You will get overwhelmed and waste a lot of time that way. Introductory books will generally cover the same basic information. Once you are familiar with the basics, then, if you want to go deeper into a certain topic you can look for more specific books, later. Initially, you just want to get an overview. Get one or two reference books for yourself (if you feel that you need to learn the theory yourself, first), and two or three for your child. Depending on the age of the child, you may want to look for books that have accurate and colourful pictures. Next look for books of activities and/or experiments. These will be geared to different age ranges and levels, so be sure to look at both the difficulty of the experiments (and the explanations given) and whether the materials needed are easy for you to acquire. Finally, you will want to get exercise books and a hardcover, non-spiral bound notebook that your child will use as a "lab book" in which to record the results and observations of their experiments. Once you have made your selections, you are ready to plan your program. It is much easier to choose the activities or experiments you want to do and then consult the appropriate sections of the reference books to learn and teach the required background theory, than it is to find a suitable experiment to go with the theory that you are teaching. Also, if you start with the experiment, then you can use the reference books to show your child how to find the answers to his or her questions that were sparked by doing the experiment.