Making Bath Salts for Mother's Day, a Primary Chemistry Lesson

In this chemistry lesson the students will learn different things about salt: everything from the chemical name, its periodic table number, see its shape under the microscope, see it dissolve in water, see it absorb fragrance, and make a mixture with salt as an ingredient.

This activity can be taught in small groups, one on one, or to a whole class. The only change needed is the amount of supplies. The lesson should last about 30-40 minutes for a second grade classroom. Add more time for younger students. The special equipment needed for this lesson is a microscope and slide and small amounts of fragrances. All other supplies can be purchased at a local store. The fragrances can be perfume sample vials or kitchen fragrances like vanilla, lemon, orange, or mint. The students will not need prior knowledge of the periodic table because this lesson is meant as an introduction. This lesson and the activities should be completed in the month of May right before Mother's Day. A key time would be during your literacy block even though science is the main focus.

Show the students a salt shaker and ask them what it is. Ask them what they know about salt. You can start a KWL chart with the students. Ask the students what we do with it. Keep charting the ideas. Teach students the "million dollar" name for salt which is Sodium. Introduce the students to the Periodic Table of Elements. Show them that salt or sodium has its own personal number which is 11. Let students explore the table. If you have an LCD projector, you may want to enlarge it so students can see all of the details on the table. Let the students know that they will be learning more about the elements and as super scientists they are getting a sneak peak.

Next, give small groups of students a spoon, clear glass, water and salt. Let them explore what they can do with these supplies. Walk around as the children are exploring. Guide a group to share when they discover that the salt is disappearing. Gather students around these "targeted" kids and have them explain to the rest of the class what they did. Introduce the word dissolve, which is like disappearing. Let the students know that the salt is disappearing into the water or dissolving. Have the small groups go back to their supplies and do the same. When they all have tried, ask the class if there is an idea they could add to the chart about salt. Guide them to say that salt dissolves in water. Then, ask the students where in a house you can dissolve salt. Take guesses until someone says the bathtub.

After that, read the story "Five Minutes Peace" by Jill Murphy (ISBN 0-590-44389-5). During the story, ask the students what the Mama elephant wants to do. They will answer that she wants to have five minutes peace to take a bath. Finish the story. When it ends, ask the students what special day is coming up. They will answer Mother's Day. Let them know they will be conducting a chemistry experiment that will be a present for their Mom. Let them know they are going to make bath salts for their own Mothers to put in the tub to have "five minutes peace". Proceed with what ingredients to get and how to mix it together. As the students are each making their bath salts for Mom to soak in the tub with, call the students over one at a time to look through a microscope. They will discover what salt is shaped like. You many want to take guesses as to the shape before they look at it. It is shaped like a cube, not a square. It is three dimensional. After each child has made their mixture, have them go on to make a card to go with their gift. Attach an explanation about the experiment along with a description about the read aloud book. When you have seen that ALL students have finished their mixtures, ask the students what happened to the fragrance. Why isn't it all wet in the bottom of the bag? They will realize that salt absorbs the fragrance. Teach them that to absorb is to "suck up" all of the wet stuff. Purposefully use a kid friendly explanation.

As a wrap up, have students become scientific investigators and look for the word sodium on the ingredient section or nutritional facts section of a food item. Have one to show in class. Anything salty will do, like chips or crackers. Students should bring in their findings to share with the class.

The recipe for bath salts is:

2 cups Epsom salts
1 cup sea salt or rock salt
1/4 teaspoon glycerin
1 vial of perfume or fragrance (2-3 drops is enough)
**if you want color, a few drops of food coloring.
1 sandwich baggie for mixing

I suggest that you do this activity outside if possible or in a well ventilated area due to the strong perfume scent. Make sure all of the baggies are tightly sealed.

The only thing I can suggest is to make sure you have a microscope on hand. If you are in an elementary only building, see if you can borrow one from the high school for the day. Make sure you give them plenty of notice. I have done this mixture before, but not the extent of showing the Periodic Table and teaching the element's scientific name. I also have never added in the microscope. I think the students are going to LOVE it!

You will be able to visually see who is making the chemical mixture correctly. There is very little room for failure. Also, you can keep a simple check system to see who brought in a nutrition label with sodium on it. If a child is having difficulty, bring in something from your own home or the lunchroom at school for the student to find the element. You may want to reserve a space in your classroom for the students to show off their labels and so other children can look for sodium on many more items.

Grade 2 Physical science

Structure of matter - The students will understand that objects can be sorted and classified based on their properties

The students will know that solids have a definite shape