Summer Science Lesson Plan: Acids and Bases

Richardson 1

Overview/Motivation:  Expose the students to acids and bases  Learn what common things are acidic and basic  Learn how indicators are used to determine acidity and basicity

Materials:  Red Cabbage Juice (for indicator, prepared ahead of time) o ½ head of red cabbage grated (or diced) o Boil in pot of water for 20-30 minutes to produce juice (must strain off cabbage), which should be purple in color o pH scale: . 2 – Red . 4 – Purple . 6 – Violet . 8 – Blue . 10 – Blue/Green . 12 – Green/Yellow  Things to test for acidity/basicity o Coke (maybe Sprite or 7-Up to get rid of color) o Bleach o Vinegar o Baking Soda (dissolved in water) o Lemon Juice o Tums/Rolaids o Ammonia o Milk o Detergent o Water  Plastic cups for mixing  Pan to put under baking soda/vinegar experiment at end

Goals:  Students should leave with a basic understanding of acids, bases, indicators, and their applications in life  They should understand the possible outcomes of acid/base reactions

Vocabulary:  Acid (I’m having trouble getting a good definition at a child’s level for these) o Taste sour  Base o Taste bitter o Feel slippery  Indicator Richardson 2

o Substance that changes color when mixed with something to reflect whether what was added was basic or acidic  Reaction o What happens when two substances are mixed together

Introduction:  Bring out bowl of cabbage juice, ask children what they think it is  Tell them it is red cabbage juice, which can be used to tell the difference between two special kinds of substances, acids and bases  Ask if they know what acid is  Explain that acids are usually things that are sour, and that some can be dangerous while others are totally normal things that they encounter every day  Ask if anyone knows what a base is  Tell them that bases usually taste bitter, make their hands feel slippery, and like acids, occur as things they encounter every day, but can also be very dangerous  Tell them that they will now do some experiments to find out what common things are acids, and what common things are bases

Demonstration:  Put the children in pairs or groups of threes, depending on how many are in the class and how much supplies we have  Set up 9 cups for each group, and pour some red cabbage juice into each cup  As a group, take some coke and pour it into the cabbage juice  Ask the children what happened to the color of the cabbage juice (it should turn more red, as coke is relatively acidic)  Tell them that because it turned red, this means that coke is an acid (can add something about how if you leave a tooth in coke for a week or 2, it will dissolve, and so on)  Repeat for each of the different products

Discussion:  Explain to the children the role of acids and bases in their everyday lives  Ask them what they think acids are used for after doing the experiment  Ask them the same for bases  Remind them that not everything is an acid or base, but that some things are neutral (like water)

Q/A:  Let them ask any questions that they have  After questions are over, quickly tell them that when acids and bases mix together, a variety of reactions can occur, some of them being very dangerous, and others being cool to watch  At this point, mix vinegar and baking soda together to make the volcano-like eruption for the children (hopefully leaving them excited and interested)