Real scientists always keep records of their work. Writing things down is a powerful way to reinforce learning. It helps a student clarify science concepts learned while doing hands-on experiments. Writing also helps a student organize information and share it with others.

Keep it simple. Use a spiral-bound notebook to keep everything in one place. Use the first couple of pages for a table of contents. Older students may want to add a conversion table for measurements. Make this journal an ongoing part of your science instruction. Always review and discuss your student's entries, asking him to explain his thoughts. If your student isn't writing yet, record the information for him. Young students can draw pictures or copy simple words.

Title: Name the experiment.

Hypothesis: Write a statement that tells what you want to prove. Asking questions can help you decide what you want to learn from the experiment. For example, do salt and fresh water have the same density? How might you determine that? Do the same objects float in both fresh water and salt water? If an object doesn’t float in fresh water, will it float in salt water? Your hypothesis could be: Salt water and fresh water have different densities.

Description: Write down how you plan to test your hypothesis. For the density experiment, you can gather different objects, test them in both fresh and salt water, and compare the results.

Materials: Write a list of all the materials you will use for the experiment, including the amounts.

Methods: Write the steps in order that you will follow in your experiment. You can also draw pictures or diagrams to show how the experiment will work. When something in an experiment can change, or vary, it is called a variable. For instance, in the density experiment the amount of salt used for the salt water solution is a variable. You want to try to keep your methods consistent during each experiment. You can then redo the experiment by changing a variable. Would changing the amount of salt in the salt water change the results? Another variable you could change would be the water temperature. Does it make a difference if the water is cold or hot?

Data and Observations: Write down everything that happens during the experiment. You may want to use a simple table to record your data. For the salt water experiment, you can make a three-column table. In the left column, list the objects that you will use. Write Salt Water at the top of the second column and Fresh Water at the top of the third. As you test each object, write down if the object fl oats or sinks. You can use just letters, F for float and S for sink.

Conclusions: Write a short summary of your results. Did you answer your question? Did you prove your hypothesis? Explain what you think happened and why. Make a graph or diagram to compare the results. For the density experiment, you could make a bar graph comparing the number of objects that floated in fresh and salt water. If your hypothesis was correct, the bar for salt water would be longer because some items floated in salt water that did not float in fresh water. A graph can help you to see patterns in the results. What can you conclude about the densities of fresh and salt water?

Write down new questions you have as a result of your experiment. What are some other experiments you can try? Be sure to include other ideas or questions you have. You could even have a page for questions or topics that your child wants to explore further. A lab journal is a work in progress. The goal isn't just to fi nish an experiment, but instead to open the doors to further exploration. There is always something new to learn in science.

SAMPLE LAB NOTEBOOK

Recently, while at the beach with my nephew, he wondered if it was easier for things to float on the ocean than on a lake.

Questions: Do things float differently in salt water? Do some things float in salt water that don’t float in fresh water? Is the density of salt water different than that of fresh water?

Title: Salt Water Density

Hypothesis: Salt water and fresh water have different densities.

Description:I want to see if some things will fl oat in salt water that don't float in fresh water. To prove this, I will use two containers of water, one fresh and one salt water. I will collect several objects and try floating them in fresh water first and then in salt water and compare the results.

Materials: 2 containers, water, 3/4 cup salt, objects: leaf, grape, penny, egg, etc.

Methods: I filled each container with plain water. I added the salt to one container and stirred until the salt dissolved. I put each object in the fresh water first, then in the salt water, and recorded what happened.

Data and Observations:I made a table listing each object. Then I made a column labelled fresh water and a column labelled salt water. I wrote S for sink or F for float as I tested each object.

Conclusions: Objects that floated in fresh water also floated in the salt water. However, the grape and the egg didn’t fl oat in fresh water, but did float in the salt water. Since the density of the egg and the grape didn't change, that tells me that salt water has a different density than fresh water. Since the egg and the grape floated on the salt water, that means the salt water is denser than the fresh water.

More Questions: Would adding more salt to the water show the difference in density more clearly? Is there another way I could compare the density of fresh and salt water? For the objects that float in both, is there a difference in how they float? Is there a way that I could measure that difference?